Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 21 June – 27 June 2023

Ahyi – Mariana Islands (USA) : Unrest at Ahyi Seamount possibly continued during 21-27 June. One small hydroacoustic signal coming from the direction of the seamount was detected by pressure sensors on Wake Island (2,270 km E) during 23-24 June. Data from the sensors on Wake Island stopped transmitting at 0414 on 24 June though no signals were detected by sensors on Saipan during the rest of the week. No surface activity was visible in satellite images.

Aira – Kyushu (Japan) : JMA reported ongoing activity at both Minamidake Crater and Showa Crater (Aira Caldera’s Sakurajima volcano) during 19-26 June. Very small eruptive events occasionally occurred at Minamidake and incandescence was observed at night. An explosion at Showa at 0438 on 22 June produced an ash plume that rose 600 m above the crater rim and drifted E and ejected blocks 500-800 m from the vent. Sulfur dioxide emissions averaged 1,400 tons per day on 22 June.

Cotopaxi – Ecuador : IG reported that moderate eruptive activity continued at Cotopaxi during 20-27 June. Several gas-and-ash emissions rose as high as 900 m above the summit and drifted S, SW, and W during 21-22 June. During 22-23 June gas plumes with low amounts of ash rose less than 200 m above the summit and drifted SW. Additional gas-and-steam emissions during 23-26 June rose as high as 500 m above the summit and drifted to the S and SW. Weather clouds often prevented direct observations.

Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 15-22 June. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 16-17, 20, and 22 June generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l. and drifted NE and SE. A thermal anomaly was identified in satellite images on 22 June; weather clouds obscured views on the other days.

Fuego – South-Central Guatemala : INSIVUMEH reported that 1-6 explosions per hour were recorded at Fuego during 21-27 June, generating daily ash plumes that rose as high as 1.1 km above the crater rim and drifted as far as 30 km S, SW, W, and NW. The ash plumes were described as dense during 22-23 June and mostly gas with diffuse ash during 24-26 June. The explosions occasionally triggered weak-to-moderate avalanches that descended multiple ravines. Minor ashfall was reported on all days, except 21 June, in areas downwind including La Soledad (7 km N), El Porvenir (8 km SE), Panimanché I and II (8 km SW), Morelia (9 km SW), Santa Sofía (12 km SW), Yucales (12 km SW), Finca Palo Verde (10 km WSW), Sangre de Cristo (8 km W), and Yepocapa (9 km WNW). Lahars descended the Ceniza (SSW) ravine on 21 June and the El Jute (ESE) ravine on 23 June.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion likely continued at Great Sitkin during 20-26 June. Minor seismicity was ongoing, and a few small earthquakes were recorded during 25-26 June. Elevated surface temperatures were identified in satellite images during 20-21 June and minor steaming was visible in satellite and webcam views during 25-27 June; weather clouds sometimes obscured webcam and satellite views on the other days.

Karangetang – Sangihe Islands : PVMBG reported that dense white gas-and-steam plumes from Karangetang were visible rising as high as 150 m and drifting in multiple directions during 21-27 June. Webcam images published in the reports on 21, 25, and 27 June showed incandescence at Main Crater (S crater) and from material on the flanks of Main Crater.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok continued during 21-27 June. Emissions mainly consisted of white steam-and-gas plumes that rose as high as 800 m above the summit and drifted W and NW; white-and-gray ash plumes rose as high as 800 m above the main crater and drifted W and NW during 22-23 June. Incandescence was visible at the summit during 24-26 June, and a webcam image taken at 2257 on 25 June showed incandescent ejecta at the summit.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 16-22 June and seismicity remained at elevated levels. The SW lava dome produced 116 lava avalanches that traveled as far as 1.8 km down the SW flank (upstream in the Bebeng and Boyong drainages). Morphological changes to the SW lava dome were due to continuing collapses of material.

Nevado del Ruiz – Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that the eruption at Nevado del Ruiz continued during 20-27 June and was characterized by gas, steam, and ash emissions, and variable seismic activity. The number of seismic events related to fluid movement, emissions, and rock fracturing fluctuated throughout the week; seismicity was highest at the beginning of the week and notably high during 22-23 June with the most intense seismicity recorded since the current period of elevated activity began on 24 March. Earthquakes occurred at distances of 1-8 km from Arenas crater at depths of 1-6 km. A period of continuous ash emissions in the afternoon of 20 June was visible in webcam images. Ashfall was reported in Manizales. Ash emissions on 21 June rose as high as 1.3 km above the crater rim, drifted WNW, and continued to rise to as high as 4 km above the summit. Incandescence from the crater was visible coincident with pulsating ash emissions during 20-23 June. Gas, steam, and ash plumes rose as high as 1.8 km and drifted NW during 24-27 June. Minor ashfall was reported in the municipalities of Villamaría (28 km NW) and Manizales (28 km NW) on 22 and 25 June respectively. The Alert Level was lowered to Yellow, Level III (the second level on a four-level scale) on 27 June. SGC noted that monitoring data was more stable in recent weeks; earthquake magnitudes were overall lower, the locations were more random, and the patterns did not indicate magma movement. Additionally, thermal anomalies at the lava dome were less intense, ash emissions had decreased, and gas emissions remained relatively stable.

Popocatepetl – Mexico : CENAPRED reported that ongoing activity at Popocatépetl during 20-27 June included 14-66 daily steam-and-gas emissions, sometimes containing minor amounts of ash. Seismic activity was characterized as daily periods of high-frequency events and variable amplitude tremors, volcano-tectonic earthquakes (2235 and 2329 on 21 June, 1520 and 2134 on 26 June), 15 minutes of low-amplitude harmonic tremor during 21-22 June, and both minor and moderate explosions. Small bursts of incandescent ejecta from the crater were observed during the night of 20 June. Minor ashfall was reported in Cuernavaca (66 km W), state of Morelos, during 20-21 June. At 0312 on 22 June a moderate explosion ejected incandescent ballistic material as far as 1.5 km from the crater and generated an ash plume that rose 2 km above the crater. Minor amounts of fell in Hueyapan (16 km SSW), state of Morelos, during 21-22 June. Minor explosions at 0405 and 0745 on 23 June produced ash plumes that rose 500 m; the first explosion ejected incandescent material short distances from the crater. Ashfall was reported in the municipalities of Ozumba (19 km W), Tepetlixpa (21 km W), Juchitepec (29 km WNW), and Amecameca (19 km NW), all within the State of México. A minor explosion was recorded at 0809 on 27 June.

Reventador – Ecuador : IG reported that the eruption at Reventador was ongoing during 20-27 June. Seismicity was characterized by 7-30 daily explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Weather clouds often hindered visual observations, though crater incandescence was visible on most nights and early mornings, and from the S-flank lava flow on 21-22 June. During 21-23 June ash emissions rose as high as 1 km above the crater and drifted to the NE, W, and NW. During 23-26 June gas-and-ash emissions rose as high as 1 km above the crater and drifted to the W and NW.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that the level of the water lake in Rincón de la Vieja’s summit crater declined during 30 May-21 June based on drone footage. A small phreatic eruption occurred at 0607 on 22 June. Several small phreatic eruptions were recorded overnight during 25-26 June. A small event at 0547 on 26 June produced a steam-and-gas plume that rose 1.5 km above the crater rim. Another small event at 0308 on 27 June produced a gas-and-steam plume that rose more than 1 km, though weather clouds and darkness obscured views.

Santa Maria – Southwestern Guatemala : INSIVUMEH reported that the eruption at Santa Maria’s Santiaguito lava dome complex continued during 20-27 June, with effusion of lava flows, explosions, and avalanches. Dome growth sometimes produced avalanches and short pyroclastic flows that traveled down the S, SW, and W flanks. Weak and moderate explosions were recorded daily. Explosions also triggered dome collapses, resulting in weak and moderate debris avalanches that descended the flanks in many directions. Incandescence at the crater and along lava flow margins was visible during most nights and early mornings. During 20-21 June ash-and-gas plumes rose 800 m and drifted W and SW. On 23 June a lahar descended the Río Cabello de Ángel, a tributary of the Nimá I and Samalá rivers on the E flank. The lahar consisted of a mixture of fine volcanic material, water, volcanic blocks up to 1 m in diameter, and tree trunks and branches.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 21-27 June. White-and-gray or white-to-brown ash plumes of variable densities generally rose as high as 1 km above the summit and drifted in multiple directions; emissions were not visible on 25 June, a partly cloudy day. A webcam image showed incandescent material at the summit and on the flanks at 0145 on 23 June. According to Info Semeru (a local news source) a pyroclastic flow traveled 5 km down the SE flanks at 1910 on 26 June. PVMBG reported that at the same time a gray-to-brown ash plume rose 1.5 km above the summit and drifted NE and E, and a webcam image showed incandescent material descending the flank.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the eruption at Sheveluch was ongoing during 15-22 June. Intense fumarolic activity at the active crater was likely associated with growth of the lava dome. A thermal anomaly over the active crater area was identified in satellite images during 16, 18-19, and 22 June.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued at low levels during 21-27 June. At 1521 on 25 June an eruptive event produced an ash plume that rose 1.3 km above the crater rim and drifted to the N, and ejected a large block 100 m from the crater. At 0036 on 27 June an ash plume rose 1.2 km and drifted N, followed by another at 0909 that rose 1.8 km and drifted E.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 21 June – 27 June 2023

Klyuchevskoy – Central Kamchatka (Russia) : KVERT reported that a minor Strombolian eruption began at Klyuchevskoy at 2323 on 22 June and a bright thermal anomaly was visible in satellite images.

Kuchinoerabujima – Ryukyu Islands (Japan) : JMA reported that the number of volcanic earthquakes increased at Kuchinoerabujima. A total of 100 shallow volcanic earthquakes were recorded during 17-26 June with most epicenters located near Furudake Crater and some located near Shindake Crater (just N of Furudake). Sulfur dioxide emissions were low, and typical white emissions rose 100-500 m above Shindake on 13 and 25 June. No changes at the geothermal area on the W flank of Shindake were observed during a field inspection during 19-20 June.

Lokon-Empung – Sulawesi : PVMBG reported continuing daily emissions at Lokon-Empung during 21-27 June. The plumes had variable densities, rose as high as 300 m above the crater rim, and were white on most days; plumes were described as white and gray on 21 June.

Mayon – Luzon (Philippines) : PHIVOLCS reported that eruptive activity continued at Mayon during 20-27 June. Slow aseismic lava effusion few a growing lava dome in the summit crater and fed lava flows that advanced down the Mi-isi (S) and Bonga (SE) drainages. Previously reported maximum lava flow lengths of 2.5 km along the Mi-isi and 1.8 km along the Bonga drainages were revised on 24 June to 1.3 km and 1.2 km, respectively; by 27 June the Mi-isi flow was 1.6 km long. The dome remained unstable and produced incandescent rockfalls and pyroclastic density currents (PDCs, or pyroclastic flows). The collapse material traveled as far as 3.3 km away from the crater. Daily steam-and-gas emissions rose as high as 800 m above the crater and drifted SW, WSW, and W. Average daily measurements of sulfur dioxide emissions fluctuated between 507 and 925 tonnes per day. Each day, seismic stations recorded 241-339 rockfall events and 1-17 PDC events, each lasting up to five minutes. On 26 June PHIVOLCS released an advisory due to increased seismic activity and ground deformation, noting that the number of volcano-tectonic earthquakes increased during the week; there were two during 20-21 June, two during 23-24 June, and 107 during 26-27 June. The increased seismicity was accompanied by a sharp increase in ground tilt on the SW part of the volcano. The Disaster Response Operations Monitoring and Information Center (DROMIC) reported that as of 1600 on 27 June, the increased unrest had affected a total of 41,488 people and displaced a total of 20,138 people from 26 barangays within the province of Albay.

Ubinas – Peru : Instituto Geofísico del Perú (IGP) reported that a new eruption began at Ubinas on 22 June after three days on increased seismicity. The seismic network recorded a total of 315 volcano-tectonic earthquakes with a maximum magnitude of 1.8 and 281 long-period earthquakes. The eruption began at 0011 on 22 June with a minor ash plume rising 1 km above the crater rim and drifted E based on seismicity and webcams. During 23-25 June IGP reported a total of 402 volcano-tectonic earthquakes with a maximum magnitude of 1.9 and 865 long-period earthquakes. Sporadic diffuse ash emissions continued during this period that rose as high as 1.5 km above the crater rim. On 23 June the Buenos Aires VAAC reported that diffuse ash plumes were visible in satellite images rising to 6.4 km (21,000 ft) a.s.l., or about 700 m above the summit, and drifting NE and NW. At 1500 they noted that continuous steam emissions occasionally accompanied by diffuse ash puffs were visible in webcam images. On 24 June small diffuse ash puffs were visible in webcam and satellite images rising 6.4-7 km (21,000-23,000 ft) a.s.l., or 700-1,300 m above the summit, and drifting NW. On 25 June continuous gas emissions with sporadic diffuse ash puffs were visible in webcam images, though the ash was too diffuse to be detected in satellite images. IGP noted that no notable deformation nor thermal anomalies were detected.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 14 June – 20 June 2023

Ahyi – Mariana Islands (USA) : Unrest at Ahyi Seamount possibly continued during 13-20 June. A few small hydroacoustic signals coming from the direction of the seamount were detected by pressure sensors on Wake Island (2,270 km E) during 16-17 June. No surface activity was visible in satellite images.

Aira – Kyushu (Japan) : JMA reported ongoing activity at both Minamidake Crater and Showa Crater during 13-19 June. Ash plumes from Showa were recorded at 1412 on 16 June that rose 1.3 km above the rim and drifted S, with another at 0710 on 17 June that rose up to 1 km and drifted E. Crater incandescence was observed at Minamidake crater during the night of 18 June.

Cotopaxi – Ecuador : IG reported that moderate eruptive activity continued at Cotopaxi during 13-20 June. Small gas-and-steam emissions rose as high as 200 m above the crater rim and drifted W and SW during 13-14 and 17 June. Several gas emissions with minor ash content rose 100 m on 15 June, and several seismic signals possibly indicating similar emissions were detected on 16 June. Gas-and-ash plumes rose 500-700 m on 18 June. Gas-and-steam plumes with minor ash content rose 100-700 m and drifted W and SW during 19-20 June.

Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 8-15 June. A thermal anomaly was identified in satellite images throughout the week. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 8-9 and 11-13 June generated ash plumes that rose as high as 4 km (11,500 ft) a.s.l. and drifted both NE and SE.

Fuego – South-Central Guatemala : INSIVUMEH reported that 1-6 explosions per hour were recorded at Fuego during 14-20 June, generating daily ash plumes that rose as high as 1.1 km above the crater rim. The explosions were often accompanied by avalanches, shock waves, and minor rumbling sounds. The ash plumes drifted 10-30 km W and SW, causing daily ashfall in areas downwind including Morelia (9 km SW), Panimaché I and II (8 km SW), Santa Sofía (12 km SW), Ceylon, El Porvenir (8 km ENE), Sangre de Cristo (8 km WSW), Yepocapa (8 km NW), La Rochela, San Andrés Osuna, and Finca Palo Verde.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion continued at Great Sitkin during 14-20 June. The thick lava flow remained confined to the summit crater, and several small earthquakes were recorded daily. Elevated surface temperatures were observed during periods of clear satellite views during 16-17 June; weather clouds obscured webcam and satellite views on the other days.

Karangetang – Sangihe Islands : PVMBG reported that dense white gas-and-steam plumes from Karangetang were visible rising as high as 75 m and drifting in multiple directions during 14-20 June. Weather clouds obscured views at times on 14, 16, and 18 June. Webcam images published in the reports showed incandescence at Main Crater (S crater) and from material on the flanks of Main Crater at 0007 on 17 June and 0440 on 18 June.

Krakatau – Sunda Strait : PVMBG reported that daily white gas-and-steam plumes rose as high as 200 m above Krakatau’s summit during 14-20 June. At 0822 on 19 June a dense white-to-gray ash plume rose 1.5 km and drifted SE.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok continued during 14-20 June. White-and-gray ash plumes rose as high as 400 m above the summit and drifted W and NW during 15 and 17-18 June; white steam-and-gas emissions were visible on the other days. Strombolian explosions at the summit crater were visible in webcam images at 2242 on 14 June, 2137 on 17 June, and 2213 on 18 June.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 9-15 June and seismicity remained at elevated levels. The SW lava dome produced 119 lava avalanches that traveled as far as 2 km down the SW flank (upstream in the Bebeng drainage). Morphological changes to the SW lava dome were due to continuing collapses of material.

Popocatepetl – Mexico : CENAPRED reported that ongoing activity at Popocatépetl during 14-20 June included 39-180 daily steam-and-gas emissions, sometimes containing minor amounts of ash. According to the Washington VAAC, daily ash plumes rose to maximum altitudes of 5.8-6.7 km (19,000-22,000 ft) a.s.l., or up to 1.3 km above the summit, and drifted generally drifted S, SW, and W, causing ashfall in local communities. At 0337 on 17 June CENAPRED noted a moderate explosion that ejected ballistic material as far as 2.5 km from the crater. Minor ashfall was reported in Hueyapan (16 km SSW), Tetela del Volcán (18 km SW), Yecapixtla (29 km SW) and Ayala (47 km SW) in Morelos, as well as Amecameca (18 km NW) and Atlautla (16 km W) in the State of Mexico during 14-15 June. Minor ashfall during 15-16 June was reported in Amecameca, Ayapango (21 km NW), Chalco (37 km NW), Ecatzingo (15 km SW), Temamatla (30 km NW), Tepetlixpa (20 km W), Tlalmanalco (26 km NW) and Tenango del Aire (28 km NW) in the State of Mexico. Reports of minor ashfall came from Ixtapaluca (42 km NW), Valle de Chalco (44 km NW), La Paz (50 km NW), Nezahualcóyotl (56 km NW), Amecameca, Atlautla, Ayapango, Cocotitlan (34 km NW), Chalco, Ecatzingo, Temamatla, Tenango del Aire, Tepetlixpa and Tlalmanalco in the State of Mexico during 16-17 June. Minor ashfall during 18-19 June was again reported in Tepoztlan (49 km W), Cuernavaca (63 km WSW), Ocuituco (24 km SW), Cuautla (43 km SW), Atlatlahucan (30 km SW), Jiutepec (59 km SW) and Emiliano Zapata (62 km SW), Morelos; Ixtapaluca, La Paz, Valle de Chalco, Nezahualcóyotl (54 km NW), Chicoloapan (48 km NW), Atlautla, Ecatzingo, Tonatico in the State of Mexico. Seismicity included periods of low-to-moderate amplitude, high-frequency tremor for 274-567 minutes each day, three volcano-tectonic earthquakes of M 1.2-1.5 were recorded during 15-16 June, and 19 minutes of low-amplitude, harmonic tremor during 16-17 June.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 12-18 June with a daily average of 18 explosions. Gas-and-ash plumes rose as high as 1.5 km above the summit and drifted SE, E, and NE. Five thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N).

Sangay – Ecuador : IG reported a high level of activity at Sangay during 13-20 June and the seismic network recorded 327-2,190 daily explosions. Gas, steam, and ash plumes were occasionally observed in IG webcam images or described in Washington VAAC volcanic activity notifications, though weather clouds sometimes prevented observations. Ash-and-gas plumes rose as high as 1.8 km above the summit and drifted W during 13-15 June. Gas-and-steam plumes rose less than 1 km during 16-17 June. Ash plumes rose as high as 1.2 km and drifted W on 18 June. Incandescence at the summit was visible in webcam images. Overnight during 18-19 June the lava flow on the SE flank was incandescent and pyroclastic material descended the SE flank as far as 500 m several times. During 19-20 June several ash-and-gas emissions rose as high as 550 m above the summit and drifted SW. Incandescence at the summit was visible multiple times. Minor ashfall was reported in Llagos parish, Chunchi (73 km SW) on 20 June.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 14-20 June. White-and-gray ash plumes rose 100-700 m and drifted N, NW, W, and S during 16 and 18-20 June; emissions were not observed on the other days.

Stromboli – Aeolian Islands (Italy) : INGV reported ongoing activity at Stromboli during 12-18 June. The Strombolian activity was centered at two vents in Area N (one each at craters N1 and N2), within the upper part of the Sciara del Fuoco, and from four vents in Area C-S (South-Central Crater) in the crater terrace. Low- and medium-intensity explosions at a rate of 3-7 per hour from Area N2 ejected mainly coarse material (bombs and lapilli), sometimes mixed with ash, up to 150 m above the vents. Sporadic explosive activity at N1 ejected mainly ash mixed with smaller amounts of coarse material. Low- to high-intensity explosions averaged 8-14 per hour from the three vents in sector S2 (Area C-S), ejecting a mix of coarse material and ash; weak spattering was sometimes observed. Weak emission of gas sometimes accompanied explosive events.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 14-19 June. A total of 526 volcanic earthquakes, 26 explosions, and 18 eruptive events were recorded by seismic monitoring stations throughout the week; activity was most notable during 15-16 June with totals of 164 volcanic earthquakes and 10 explosions. Ash plumes were observed daily; the tallest plumes rose 2 km above the crater rim on 15 and 16 June. Continuous emissions during 0936-1355 on 16 June rose as high as 2 km and drifted SE and SW. Some events ejected large volcanic blocks up to 400 m from the crater during 14-18 June. Incandescent ejecta from explosions during the nights of 18-19 June were sometimes visible in webcam images. Occasional ashfall and rumbling noises were reported in Toshima village (3.5 km SSW).

Taal – Luzon (Philippines) : PHIVOLCS reported continuing low-level unrest at Taal during 13-20 June characterized by elevated seismicity, upwelling in the lake, and sulfur dioxide gas emissions. There were 20-38 daily volcanic earthquakes recorded during 13-17 June and a total of 11 recorded during 19-20 June. There were 2-46 daily periods of tremor, each lasting 2-67 minutes long. Daily white steam-and-gas plumes (sometimes voluminous) rose as high as 3 km above the lake and drifted NE, NW, and SW; voggy conditions were reported during 16-17 June. Upwelling gasses and hot fluids in the lake were visible during 14-17 June. Sulfur dioxide emissions averaged 7,643 and 2,177 tonnes per day on 15 June and 19 June, respectively.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 14 June – 20 June 2023

Kilauea – Hawaiian Islands (USA) : HVO reported that the eruption on the floor of Kilauea’s Halema’uma’u Crater continued during 14-20 June. Activity was characterized by effusion primarily from the vent on the SW wall of the crater, circulation within the crater lakes, slow rise of the crater floor, eruptive tremor, and elevated sulfur dioxide levels (4,500-6,300 tonnes per day). Lava flows from vents at the base and top of a cone on the SW wall of Halema’uma’u entered the lava lake in the far SW portion of the crater; intermittent spattering from the cone was visible at night. Other eruptive vents within the SW lava lake (previously dome fountains) had ceased by 13 June. The surface of the SW lava lake slowly rose about 0.5 m per day during 13-15 June. Additionally, lava circulation continued within the central basin. At 0800 on 15 June the top of the SW wall cone collapsed, leading to nearly constant spattering from the top vent and a change in activity from the base vent. The central basin level has been dropping relative to the rising crater floor (due to lava accumulation underneath), allowing several flows from the SW lava lake to cascade into the basin. By 16 June, renewed activity on the SW wall was producing vigorous fountaining to at least 10 m high with some higher spatters, with lava flowing into the SW lake. This activity continued into 19 June as the crater floor continued to rise, circulation in central basin slowed, and flows from the base of the SW wall cone changed paths. Around 1600 on 19 June activity rapidly declined, shown by a drop in the SW lake surface, decreased seismicity, and a transition to inflationary tilt from the deflationary trend of the previous two days. Seismic activity remained low and on 20 June HVO reported that the eruption had paused.

Lokon-Empung – Sulawesi : In a press release PVMBG reported increased emissions at Lokon-Empung on 13 June with dense white plumes rising 400 m above the rim of Tompaluan Crater and drifting S; a total of 12 earthquakes indicating emissions were recorded by the seismic network. The emissions were followed by a period of continuous tremor during 1835-2100. White steam-and-gas emissions of variable densities rose as high as 500 m and drifted N, W, and S during 14-20 June. During 2023 white emissions generally rose 20-150 m above the crater rim and seismicity was generally dominated by 1-2 daily shallow volcanic earthquakes.

Mayon – Luzon (Philippines) : PHIVOLCS reported that lava-dome extrusion at Mayon’s summit crater continued during 14-20 June, generating frequent lava flows and pyroclastic density currents (PDCs, or pyroclastic flows), and additional evacuations. Sulfur dioxide emissions ranged from 149-193 tonnes per day (t/d) during 13-14 June, rising to 826-1,004 t/d during 15-18 June (above normal baseline values of 500 t/d), and then dropping to 389 t/d on 19 June. The total number of rockfalls ranged from 265-309 events per day, resulting from partial collapses of the growing lava dome and lava flows. PDCs were recorded during 13-14 June (7), 14-15 June (3), 15-16 June (13), 16-17 June (9), 17-18 June (11), 18-19 June (5), and 19-20 June (2); each event lasted 2-6 minutes based on seismic signals. Lava flows remained active, with debris collapses throughout the week sending material into the Mi-Isi (S) and Bonga (SE) drainages. By 20 June lava flows reached 2.5 km down the Mi-Isi and 1.8 km down the Bonga drainages, and debris flows extended 3.3 km from the crater. Ashfall during 15-16 June was reported in the communities of Buga (36 km W), Nabonton (9 km W), Ligao (16 km W), Purok 7 (12 km S), and San Francisco (11 km SW). The Disaster Response Operations Monitoring and Information Center (DROMIC) reported that by 20 June there had been 38,975 people affected, 20,139 displaced, and 18,749 taking shelter in 28 evacuation centers across Albay.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that small phreatic explosions continued at Rincón de la Vieja during 14-19 June and gas-and-steam emissions were sometimes continuous. There were 1-3 daily events during 14-16 and 18 June; most were not observed due to darkness. A small event at 1804 on 18 June produced a steam-and-gas plume that rose 2 km above the crater rim.

Ubinas – Peru : Instituto Geofísico del Perú (IGP) reported that seismicity at Ubinas had been increasing since mid-May, and that during 1-18 June fumarolic plumes rose 500 m above the crater rim.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 7 June – 13 June 2023

Aira – Kyushu (Japan), : JMA reported ongoing activity at both Minamidake Crater and Showa Crater during 5-12 June. Eruptive events at Showa were recorded at 0211, 0352, 0440, and 1436 on 5 June and generated ash plumes that rose as high as 1.5 km above the crater rim and sometimes drifted E and SE. Explosions at Minamidake produced ash plumes that rose 1.5 and 2.5 km above the crater rim at 0012 on 5 June and 1401 on 7 June, respectively, and ejected blocks 500-700 m from the vent. Ash-and-gas emissions were continuous with plumes rising as high as 1.5 km and then declining to 800 m during 1401-1505 on 7 June, and drifting SE. Since the volcano is so active, JMA noted that only emissions above a certain threshold of density and height get reported; at 1505 the emission characteristics declined to below that threshold.

Cotopaxi – Ecuador : IG reported that moderate eruptive activity continued at Cotopaxi during 6-13 June. Seismic activity was mainly characterized by long-period earthquakes and tremors associated with daily emissions; one volcano-tectonic event was recorded during 6-7 June. Small gas-and-steam emissions rose as high as 300 m above the crater rim during 6-9 June. A small lahar was detected by the seismic network on 8 June and descended the NW flank. Several daily ash-and-gas emissions were visible during 10-13 June and were continuous during part of 12 June. The plumes rose 200-600 m above the crater rim and drifted NW, W, and SW.

Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 1-8 June. A thermal anomaly was identified in satellite images during 2, 4, and 7-8 June. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 5-8 June generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l. and drifted NE and SE.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion continued at Great Sitkin during 6-13 June, producing a thick lava flow confined to the summit crater. Seismicity remained low. Steam emissions were visible in satellite images during 7-8 June and slightly elevated surface temperatures were identified on 8 June; weather clouds prevented satellite and webcam observations on the other days.

Karangetang – Sangihe Islands : PVMBG reported that daily white gas-and-steam plumes from Karangetang were visible rising as high as 200 m and drifting W, NW, and NE during 7-13 June. Webcam images published in the daily reports showed incandescence at Main Crater (S crater) and from material on the flanks of Main Crater at 2225 on 7 June and 2051 on 9 June.

Krakatau – Sunda Strait : PVMBG reported that multiple dense ash plumes were visible rising above Krakatau’s summit during 8-11 June. On 8 June at 0746 a gray ash plume rose 500 m and drifted SW, and at 1537 a dark-gray ash plume rose 1 km and drifted SW. At 0746 on 9 June gray plume rose 800 m and drifted SW; a dark gray ash plume at 0846 rose 3 km and drifted SW. At 0423, 1431, and 1750 on 10 June gray ash plumes rose 1.5-3.5 km and drifted NW. A webcam image showed incandescent material being ejected above the crater at 0455. At 0030 on 11 June a dense gray ash plume rose 2 km and drifted NW. A webcam image about a half an hour later, at 0102, showed incandescent material being ejected above the crater. Diffuse white gas-and-steam plumes rose just 50 m during 12-13 June.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok continued during 7-13 June. Daily white-and-gray ash plumes rose as high as 700 m above the summit and drifted SW, W, and NW.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 2-8 June and seismicity remained at elevated levels. The SW lava dome produced 99 lava avalanches that traveled as far as 2 km down the SW flank (upstream in the Bebeng drainage). Morphological changes to the SW lava dome due to continuing collapses of material were evident in webcam images.

Nyiragongo – DR Congo : The Observatoire Volcanologique de Goma (OVG) reported that the eruption at Nyiragongo continued during 5-11 June and sulfur dioxide levels in the emissions remained low. Crater incandescence and gas emissions were visible at 1800 on 10 June

Reventador – Ecuador : IG reported that the eruption at Reventador was ongoing during 6-13 June. Seismicity was characterized by explosions, long-period earthquakes, harmonic tremor, and tremor associated with emissions. Though weather clouds hindered visual observations of emissions during 6-7 June, several explosions overnight ejected incandescent material onto the flanks; some of the material rolled down the E flank. During 7-10 June several steam-and-ash emissions rose as high as 1 km above the crater rim and drifted W. Crater incandescence was visible during overnight hours and incandescent blocks sometimes rolled 400-500 m down the flanks. Crater incandescence was visible overnight during 11-13 June. Weather conditions prevented views on 11 June. Gas-and-ash plumes rose 600-800 m and drifted W during 12-13 June.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 7-13 June. A dense gray ash plume rose 500 m above the summit and drifted SW at 0534 on 8 June. White-and-gray ash plumes rose 300-400 m above the summit and rifted W and SW at 1214 on 8 June, 0942 on 9 June, and 0653 on 10 June.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the eruption at Sheveluch was ongoing during 1-8 June. Intense fumarolic activity at the active crater was likely associated with growth of Karan lava dome. A daily thermal anomaly over the active crater area was identified in satellite images.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued, though monitoring parameters had been showing a declining trend. Blocks had not been ejected more than 1 km from the crater after 15 February and the number of explosions had decreased since March. GNSS (Global Navigation Satellite Systems) deformation measurements did not indicate accumulating magma beneath the W part of the island and the number volcanic earthquakes in that area was low. Eruptive activity during 7, 9-10, and 12 June generated ash plumes that rose 1-1.5 km above the crater rim and drifted in multiple directions. An explosion at 1803 on 7 June produced an ash plume that rose 1.4 km and drifted E. Explosions were recorded at 0230 on 9 June and 1758 on 10 June, though details of any emissions were unknown.

Taal – Luzon (Philippines) : PHIVOLCS reported continuing low-level unrest at Taal during 6-13 June characterized by elevated seismicity, upwelling in the lake, and sulfur dioxide gas emissions. Volcanic tremor located at shallow depths along the Daang Kastila fissure was continuous with almost 166 hours recorded during 2-9 June; periods of volcanic tremor also took place 4-7 times each day during 9-12 June, each lasting 2-97 minutes. There were 1-11 volcanic earthquakes recorded on most days. Upwelling gasses and hot fluids in the lake continued to be visible almost daily, and voluminous white steam-and-gas plumes that rose as high as 3 km above the lake drifted NW, E, and SSE. Daily sulfur dioxide emissions averaged 2,941-6,884 tonnes per day. The steam-and-gas plumes produced voggy conditions in the caldera during 6-9 June, prompting an advisory to the public to be issued on 7 June.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 7 June – 13 June 2023

Ahyi – Mariana Islands (USA) : Unrest at Ahyi Seamount continued during 6-12 June. Possible hydroacoustic signal was detected by pressure sensors on Wake Island (2,270 km E) during 6-8 June, and multiple hydroacoustic signals were detected during 9-11 June. No surface activity was visible in partly cloudy and partly clear satellite images.

Kilauea – Hawaiian Islands (USA) : A new eruption at Kilauea began at 0444 on 7 June with the burst of tall lava fountains from a vent on the central part of the Halema’uma’u Crater floor. Soon after, lava fountains were active along multiple fissures on the crater floor, and along one fissure that bisected the SW crater wall. Between 0800-0900 the sulfur dioxide emission rate was about 65,000 tonnes per day. Residents of Pahala, 30 km downwind of the summit, reported minor deposits of fine gritty ash and Pele?s hair. Lava flows inundated the crater floor (about 1.5 square km) and added about 6 m depth of new lava within a few hours. A small spatter cone had formed at the vent on the SW wall by midday, and lava from the cone was flowing into the active lava lake below. Fountain heights had decreased from the onset of the eruption and were 4-9 m high by 1600, with occasional higher bursts. Inflation switched to deflation and summit earthquake activity greatly diminished shortly after the eruption onset. At 0837 on 8 June HVO lowered the Volcano Alert Level to Watch and the Aviation Color Code to Orange because the initial high effusion rates had declined, and no infrastructure was threatened. The lava lake had dropped by about 2 m likely due to gas loss by the morning of 8 June. The drop left a wall of cooled lava around the margins of the crater floor. Multiple lava fountains were active in the central E part of the lake and fountains rose as high as 10 m. The spatter cone continued to build over the SW wall vent; lava flows from the vent fed the SW part of the lava lake. The preliminary average effusion rate for the first 24 hours of the eruption was about 150 cubic meters per second, though the estimate did not account for vesiculated lava and variations in crater floor topography. The effusion rate during the very earliest phases of the eruption appeared to be significantly higher than the previous three summit eruptions based upon the rapid coverage of the entire crater floor. During 8-9 June multiple lava fountains remained active and rose up to 10 m high. The SW wall vent continued to effuse lava into the crater lake which had increased in depth by about 1.5 m. Active lava and vents covered much of the W half of the crater floor, arranged in a broad horseshoe shape around a central uplifted area. This feature in the basin of the 2021-22 lava lake was described as the “western lava lake” from prior eruptions and had reactivated along with a smaller circular pool just SE of the lake. An active lava lake centered within the uplifted area was fed by a vent in its NE corner. A much smaller area of lava was active in the E portion of the crater floor. The sulfur dioxide emission rate was about 11,000 tonnes per day on 9 June and about 8,900 tonnes per day on 10 June. During 10-12 June multiple lava fountains remained active and were up to 9 m high, and the SW wall vent continued to effuse lava into the crater lake. The active features in the E portion of the lake had stagnated during 10-11 June. Sulfur dioxide emissions averaged 7,400 tonnes per day on 11 June. The W part of the lake rose about 1 m during 11-12 June, likely due to the construction of a levee around the pond. Gas plumes rose to 2.4-3 km (8,000-10,000 ft) a.s.l. and were trapped under a weather inversion layer. Activity decreased during 12-13 June and only a few small lava fountains were active. The western lake and the smaller lava pond in the central portion of the crater floor remained active, along with the vent on the SW wall.

Mayon – Luzon (Philippines) : PHIVOLCS reported that the rate of lava-dome extrusion at Mayon’s summit crater increased, leading to an Alert Level increase and evacuations. Sulfur dioxide emissions were at or near baseline levels of 500 tonnes per day, averaging 574 and 332 tonnes per day on 6 and 7 June, respectively. The total number of rockfalls increased from 54 during 1-4 June to 267 during 5-8 June. Additionally, the volumes of the individual rockfall events became larger on 3 June. The rockfalls were generated by partial collapses of the growing lava dome and indicated an increasing extrusion rate. Three pyroclastic density currents (PDCs, or pyroclastic flows) were recorded at 0618, 0953, and 1100 on 8 June, each lasting 4-5 minutes based on the seismic signals. The PDCs traveled as far as 2 km down the Mi-Isi (S), Bonga (SE), and Basud (E) drainages and indicated that new, less degassed lava was collapsing from the summit dome. The Alert Level was raised to 3 (on a 0-5 scale) at 1200 on 8 June and recommended the evacuation of the 6-km radius Permanent Danger Zone. Six PDCs generated by collapses at the lava dome and 199 rockfall events were recorded during 8-9 June, based on seismic data and visual observations. Material from the rockfalls and PDCs descended the S flank within 2 km. Steam-and-gas plumes from the dome rose 800 m and drifted S, and light-brown ash plumes from the rockfalls drifted S. Minor crater incandescence from newly extruded lava and incandescent rockfalls were observed through the night. Rockfall events continued during 9-10 June with total of 59. A new dome, contacting a part of the remnant dome on the SE part of the crater floor, was visible during the morning of 10 June. Sulfur dioxide emissions increased to moderate levels, averaging 1,205 tonnes per day that same day. The DROMIC report stated that 9,314 people from 21 neighborhoods (barangays) spanning six municipalities were in evacuation centers by 10 June. A total of 177 rockfalls traveled as far as 700 m down the S and SE flanks during 10-11 June. Plumes of steam and gas from the dome and minor ash plumes from the rockfalls descended the flanks and then drifted E and SE. Incandescence from the dome and rockfalls was visible at night. Sulfur dioxide emissions averaged 642 tonnes per day on 11 June. Lava flows emerged at about 1947 on 11 June and produced two 500-m-long lobes; lava avalanches from the ends of the flows descended the Mi-Isi, Bonga, and Basud drainages within 2 km of the summit. Effusion of the lava flows was preceded by slight inflation at the upper flanks based on tiltmeter data and accompanied by minor seismicity. During 11-12 June the monitoring network recorded 260 rockfall events, and three collapses at the dome that produced PDCs (each lasting 2-4 minutes). The lava flows continued to be active. There were 14,360 people that had evacuated by 12 June; of those, 584 people were staying in places other than evacuation centers. During 12-13 June the monitoring network recorded 221 rockfall events and collapses at the dome that produced PDCs (each lasting 2-4 minutes). Lava continued to slowly effuse at the summit crater and collapsed material traveled 1 km down the Mi-isi and Bonga drainages. One PDC lasting two minutes was observed and detected by the seismic network. Diffuse ash from the rockfalls and steam-and-gas emissions from the dome drifted downslope and then NE. Rockfalls exposed incandescent material at the summit. By 13 June a total of 16,152 people had evacuated; of those, 15,493 people were in evacuation shelters and 659 people were staying with friends and family.

Nyamulagira – DR Congo : The Observatoire Volcanologique de Goma (OVG) reported that the eruption at Nyamulagira continued at low levels during 5-11 June based on satellite images.

Popocatepetl – Mexico : CENAPRED reported that there were 35-101 daily steam-and-gas emissions, sometimes containing minor amounts of ash, rising from Popocatépetl during 6-13 June. Daily minor or moderate explosions were recorded during 6-11 June. Periods of low-to-moderate amplitude, high-frequency tremor lasting from 34 minutes to just over six hours were recorded each day. A few volcano-tectonic earthquakes with magnitudes of 1.2-2 were recorded during 6, 8, and 11-12 June. According to the Washington VAAC daily ash plumes rose 5.8-7 km (19,000-23,000 ft) a.s.l., or around as high as 1.6 km above the summit, and drifted generally drifted SE, SSE, S, and SW. Minor ashfall was reported in Hueyapan (16 km SSW), Zacualpan de Amilpas (30 SSW), Temoac (32 SSW), Jonacatepec de Leandro Valle (43 SSW), and Tetela del Volcán (18 SW), all within the Mexican state of Morelos during 11-12 June, and in Hueyapan, Yecapixtla (30 km SW), Ayala (45 km SW), and Jantetelco during 12-13 June.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that phreatic explosions continued at Rincón de la Vieja during 6-13 June, with multiple phreatic events recorded during 6-8 June. A 14-minute-long event that began at 0142 on 7 June was comprised of two pulses of gas-and-steam that rose 1 km above the crater rim. At 0942 on 8 June a plume of steam and gas rose 2.5 km above the crater rim, followed at 1810 by a moderate phreatic eruption that ejected lake water with sediment to less than 100 m above the crater rim and produced a white steam plume that rose 3 km and drifted W. Two events recorded at 0138 and 2037 on 9 June were similar in energy to the 8 June event at 1810. Gas emissions were visible on 10 June. Small phreatic events at 0357, 0521, and 0546 on 11 June produced white steam-and-gas plumes that drifted W. White steam-and-gas plumes from small phreatic events at 1031 and 1039 on 12 June rose as high as 1 km above the crater rim.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 31 May – 6 June 2023

Aira – Kyushu (Japan) : JMA reported ongoing activity at both Minamidake Crater and Showa Crater during 29 May-5 June. On 29 May sulfur dioxide emissions were high at 2,900 tons per day. Crater incandescence was observed nightly at both craters during 29 May-2 June, and very small eruptive events periodically occurred. Eruptive events at Minamidake at 0237 and 0454 on 4 June produced ash plumes that rose about 1.1 km above the crater rim. An explosion at 0012 on 5 June generated an ash plume that rose 1 km and drifted SE, and ejected blocks 500-700 m from the crater. At Showa, eruptive events at 0211, 0352, 0440, and 1436 on 5 June generated ash plumes that rose 1.3-1.5 km above the crater rim and drifted SE and E, or rose straight up; blocks were ejected as far as 300 m from the crater. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from both craters.

Bezymianny – Central Kamchatka (Russia) : KVERT reported that eruptive activity at Bezymianny was generally characterized by lava effusion, gas-and-steam emissions, and lava dome incandescence during 25 May-1 June. A daily thermal anomaly was identified in satellite images.

Bulusan – Luzon (Philippines) : In a special advisory, PHIVOLCS reported that from 0500 on 31 May to 1500 on 1 June the seismic network at Bulusan recorded a total of 19 volcanic earthquakes. Out of those, five were located at depths of 2.7-6.6 km beneath the E part of the volcano and had local magnitudes of 1.8-2.7. Minor white steam emissions from the summit crater and active vents on the SE flank were occasionally visible. Ground deformation data from electronic tiltmeter stations continued to record short-term inflation of the SE flanks, first detected in December 2022.

Cotopaxi – Ecuador : IG reported that moderate eruptive activity continued at Cotopaxi during 30 May-6 June. Seismic activity was mainly characterized by long-period earthquakes and tremors associated with daily emissions. Although weather clouds often obscured views, emissions were visible almost daily. During 30-31 May ash-and-gas emissions rose as high as 500 m above the summit and drifted W and NW. A tremor signal associated with an ash emission was detected on 1 June, though weather clouds prevented visual confirmation; ashfall was reported in San Ramón (108 km N) and San Agustín de Callo (16 km WSW). Multiple ash emissions were reported on 3 June; ash plumes rose as high as around 1 km above the summit and drifted SW, W, and NW. During 4-5 June several gas-and-ash emissions rose 400-800 m and drifted W and SW.

Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 25 May-1 June. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 25 and 27-28 May generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l. and drifted NE. A thermal anomaly was identified in satellite images on 26 May and 1 June.

Fuego – South-Central Guatemala : INSIVUMEH reported that daily gas emissions rose from Fuego during 31 May-4 June. During 2-3 June minor explosions occurring at a rate of two per hour produced diffuse ash plumes that rose 450 m above the summit and drifted 10 km W and SE. Minor ashfall was reported in El Zapote (10 km SSE), La Rochela (8 km SSW), and San Andrés Osuna (12 km SSW).

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion continued at Great Sitkin during 30 May-6 June producing a thick lava flow confined to the summit crater. Seismicity remained low; a few local earthquakes were recorded daily. Slightly elevated surface temperatures were identified in satellite images during 30-31 May and 3-4 June. Satellite data during 5-6 June confirmed that the flow was expanding E.

Ibu – Halmahera : PVMBG reported that Ibu continued to erupt during 31 May-6 June. White-and-gray ash plumes of variable densities rose as high as 1 km above the summit and drifted in multiple directions during 31 May-1 June. According to the Darwin VAAC ash plume rose 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted SE, E, and NE on 2 and 5 June.

Iliamna – Alaska Peninsula : AVO reported that seismic activity at Iliamna began to increase at around 1200 on 5 June. Initially earthquakes occurred about every one minute, then became more closely spaced. The source of the activity was possibly from movement of magma or hydrothermal fluids beneath the volcano, though similar activity had been observed before large mass movements or avalanches; AVO could not rule out either. The earthquake activity culminated in an ice-rock avalanche just before 1714. There was no visual confirmation, but the signals matched historical observations associated with avalanches at Red Glacier on the E flank. Seismicity declined to background levels.

Krakatau – Sunda Strait : PVMBG reported that at 1434 on 6 June a dense gray ash plume from Anak Krakatau rose around 500 m above the summit and drifted NW.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok continued during 31 May-6 June. Ash plumes were periodically visible through the week. Dense white-and-gray ash plumes rose as high as 600 m above the summit and drifted W and NW on 1 June. Ash plumes on 2 June rose as high as 1 km and drifted W and SW. A dense ash plume rose 550 m and drifted SW on 5 June.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 26 May-1 June and seismicity remained at elevated levels. The SW lava dome produced 155 lava avalanches that traveled as far as 2 km down the SW flank (upstream in the Bebeng and Boyong drainages) and one that traveled 500 m NW (upstream of the Senowo River). Morphological changes to the SW lava dome due to continuing collapses of material were evident in webcam images.

Nevado del Ruiz – Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that the eruption at Nevado del Ruiz continued during 31 May-6 June and was characterized by periodic gas, steam, and ash emissions, and thermal anomalies at the lava dome in Arenas Crater. Seismicity fluctuated at low levels; on 31 May SGC stated that during the past several days seismicity had decreased compared to the previous weeks. Daily gas-and-steam emissions were visible in webcam images and contained ash on most days; emissions rose as high as 2 km above the crater and mainly drifted NW. Ash emissions were confirmed in satellite images on the other days according to the Washington VAAC. A significant thermal anomaly was observed within the crater on 31 May. That same day a sulfur odor was reported in Cerro Gualí. Minor ashfall was reported in the municipalities of Villamaría (28 km NW) and Manizales (28 km NW) on 4 June.

Nyiragongo – DR Congo : The Observatoire Volcanologique de Goma (OVG) characterized activity at Nyiragongo during 27 May-4 June as normal. Sulfur dioxide emissions were low. Faint incandescence at the crater was observed at 1900 on 4 June.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 29 May-4 June with a daily average of 24 explosions. Gas-and-ash plumes rose as high as 2.1 km above the summit and drifted NW and W. Six thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Minor inflation continued to be detected near Hualca Hualca (4 km N).

Sangay – Ecuador : IG reported that the eruption at Sangay continued at a high level during 30 May-6 June, though weather clouds often prevented visual observations. The seismic network recorded 504-528 explosions per day during 30 May-2 June and 158-384 per day during the rest of the week. Periods of occasional-to-frequent ash plumes were reported almost daily. Incandescence at the crater was visible during 31 May and 3-4 June; incandescent material traveled 1 km down the SE flank. Ashfall was reported on 1 June in Cebadas Parish, Chimborazo Province (33 km WNW). On 4 June an ash plume rose to 1.1 km above the crater and drifted W and SW. During 4-5 June incandescent material traveled 1 km down the SE flank. Several steam-and-ash plumes rose as high as 1.1 km above the summit and drifted W.

Santa Maria – Southwestern Guatemala : INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 31 May-6 June. Effusion from the Caliente dome complex fed lava flows that descended the San Isidro and Zanjón Seco drainages on the W and SW flanks; the main lava flow was 4.3 km long and remained active. Avalanches of material from the growing dome and occasional explosions descended all flanks of the dome, and avalanches from the margins of lava flows descended the S and SW flanks. Incandescence from the dome and lava flows was visible during the nights and early mornings. An average of 1-2 explosions per hour were recorded on most days, generating ash-and-steam plumes that rose up to 1 km above the dome and on some days drifted S and SE.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 31 May-6 June. Steam-and-gas plumes were occasionally visible, though weather clouds often obscured visual observations. White-and-gray ash plumes rose 300-500 m above the summit and drifted W and NW on 3 June.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level unrest continued at Semisopochnoi during 30 May-6 June. Seismicity remained low and few earthquakes were detected. Minor steam emissions were occasionally visible in webcam images on 31 May and 2 and 4 June.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the eruption at Sheveluch was ongoing during 25 May-1 June. Intense fumarolic activity at the active crater was likely associated with growth of Karan lava dome. A thermal anomaly over the active crater and Karan dome area was identified in satellite images during 25-30 May; weather clouds obscured the volcano on the other days. Plumes of ash, originally deposited during the 10-13 April eruption and resuspended by strong winds, were visible in satellite images drifting 120 km ESE during 27-28 May.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 29 May-5 June. At 1407 on 30 May an explosion generated an ash plume that rose 800 m. Incandescence at the crater was visible at night during 2-5 June. Four eruptive events occurred during 4-5 June. Ash plumes rose to 1.1 km and drifted E and S at 1455 and 2327 on 4 June, respectively. At 1037 and 2349 on 5 June ash plumes rose 1-1.1 km and drifted E.

Taal – Luzon (Philippines) : In a 2 June advisory PHIVOLCS reported continuing low-level unrest at Taal. Starting at 0635 on 2 June relatively weak but continuous volcanic tremor located at shallow depths along the Daang Kastila fissure was recorded by all 15 seismic stations of the Taal Volcano Network. At the same time webcams recorded upwelling in Main Crater Lake on Taal Volcano Island (TVI) and more intense thermal anomalies in the N portion of the lake. Pronounced inflation in the SW part of Taal Volcano Island was detected towards the end of May, following a longer phase of deflation in that same sector. Sulfur dioxide gas emissions had slightly increased during the previous two weeks, averaging 5,360 tonnes per day during 22 May-1 June, higher than the 3,000 tonnes per day average recorded during 1 April-21 May. Emissions averaged 5,831 tonnes per day on 1 June. PHIVOLCS stated that a new phase of magma degassing at depth was likely driving the increased shallow hydrothermal activity. At 2230 on 3 June visible upwelling of volcanic fluids in the lake produced voluminous steam-rich plumes that rose 3 km above TVI. Significant vog was detected in the caldera and reported by residents in the municipalities of Balete (E of Taal Lake), and Laurel and Agoncillo (both W of Taal Lake), Batangas. Upwelling of how fluids in the lake continued during 4-7 June and steam-rich plumes rose as high as 3 km above the lake and drifted NE and NNE. Sulfur dioxide gas emissions averaged 9,391 tonnes per day on 5 June and 7,680 tonnes per day on 6 June; significant vog persisted over the Taal region.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 31 May – 6 June 2023

Ahyi – Mariana Islands (USA) : Unrest at Ahyi Seamount continued during 30 May-7 June. A possible hydroacoustic signal was detected by pressure sensors on Wake Island (2,270 km E) during 2-3 June. No activity was visible in cloudy satellite images.

Karangetang – Sangihe Islands : Webcam images of Karangetang published in PVMBG daily reports periodically showed incandescence at Main Crater (S crater) and from material on the flanks of Main Crater during 31 May-6 June. Daily white gas-and-steam plumes were visible rising as high as 150 m above the summit and drifting in various directions. According to the Darwin VAAC ash plumes rose as high as 2.1 km (7,000 ft) a.s.l. and drifted SE and E during 2-4 June. The Alert Level remained at 3 (on a scale of 1-4) and the public were advised to stay 2.5 km away from Main Crater with an extension to 3.5 km on the S and SE flanks.

Kilauea – Hawaiian Islands (USA) : HVO reported that earthquake activity and changes in the patterns of ground deformation beneath Kilauea’s summit began to be detected during the evening of 6 June. The data indicated magma movement towards the surface. At about 0444 on 7 June incandescence in Halema’uma’u Crater was visible in webcam images indicting that a new eruption had begun.

Mayon – Luzon (Philippines) : Daily visual and webcam observations of Mayon’s summit crater revealed more frequent rockfalls at the summit lava dome starting in the last week of April, indicating aseismic dome growth. The lava dome increased in volume by about 83,000 cubic meters during 3 February-9 May, with a total addition of nearly 164,000 cubic meters since 20 August 2022. Sulfur dioxide emission averages were as high as 576 tons per day on 29 April and 162 tons per day on 23 May. A total of 26 volcanic earthquakes had been recorded since 1 April. Electronic Distance Measuring (EDM), precise leveling, continuous GPS, and electronic tilt monitoring data showed that the volcano had been slightly inflated, especially on the NW and SE flanks, since 2020. Short-term inflation on the upper flanks had been detected since February. From 0500 on 4 June to 0500 on 5 June the number of rockfalls increased from an average of 5 events per day to 49 events per day.

Nyamulagira – DR Congo : On 1 June the Observatoire Volcanologique de Goma (OVG) reported that seismicity at Nyamulagira remained at lower levels, similar to those recorded before the 17 May increase in activity. Incandescence above the crater had been absent for the past three days, but satellite imagery showed continuing lava effusion within the summit crater. The recent flows on the flanks covered an estimated 0.6 square kilometers.

Popocatepetl – Mexico : CENAPRED reported that during 30 May-6 June activity at Popocatépetl consisted of seismic tremor, a few explosions, emissions of steam and gas, with occasional ash, and ejections of incandescent material. There were 67-315 daily steam-and-gas emissions, sometimes containing minor amounts of ash, with the highest number recorded during 30-31 May. Overall activity decreased during the week. Explosions at 1423 and 1708 on 30 May produced gray ash plumes. During 30-31 May incandescent material was ejected from the vent short distances onto the flank. High-frequency tremor was recorded by the seismic network for around eight and a half hours, and was associated with nearly continuous emissions of steam, gas, and ash. Ashfall was reported in Ayapeango (22 km NW) and Acatzingo (100 km W), in the State of Mexico. A M1.6 volcano tectonic (VT) earthquake was recorded at 0952 on 31 May. The Washington VAAC stated that although ash emissions continued to be visible in satellite and webcam images drifting SSE, the intensity of the emissions had decreased. CENAPRED stated on 1 June that tremor signals had significantly decreased during the previous few days, and on 2 June that overall activity had also decreased. Periods of high-frequency, low-amplitude tremor continued to be detected during the rest of the week. A period of tremor recorded during 1635-1850 on 3 June was associated with diffuse ash emissions that drifted SE. According to the Washington VAAC ash plumes during 1-3 June rose 5.5-6.7 km (18,000-22,000 ft) a.s.l., or as high as 1.3 km above the summit, and drifted SW, SSW, and SE. A minor explosion occurred at 0739 on 4 June. A minor explosion occurred at 1211 on 5 June and a M1.2 VT earthquake was recorded at 1818.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that increased eruptive activity continued at Rincón de la Vieja during 30 May-6 June. Seismic instruments continued to record low-magnitude volcano-tectonic earthquakes located S of the Pailas sector of Parque Nacional Rincón de la Vieja. Reports describing phreatic eruption events were issued almost daily. A phreatic event at 2215 on 30 May ejected incandescent material within the vicinity of the crater. A small phreatic eruption at 1753 on 31 May generated a small pyroclastic flow that traveled a short distance from the crater. Moderate phreatic eruptions were recorded during 1-2 June; the most energetic event occurred at 0902 and generated a plume of steam, gas, and ash that rose to 1.5 km above the crater and drifted N. Eruptive events were recorded during 3-4 June. The most energetic event occurred at 0624 on 3 June and generated a steam-and-gas plume that rose 1.5 km and drifted W. An eruptive event at 0526 on 4 June first generated emissions that rose to 500 m, followed at 0529 by a second plume of steam-and-gas rose to 3.5 km above the crater and drifted N. Steam-and-gas plumes with low ash content were generated from eruptive events during the nights of 4-5 June; the plumes rose 1-1.5 km above the crater and drifted W. At 0259 on 6 June a small phreatic eruption generated a plume that rose to 3 km and drifted NW.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 24 May – 30 May 2023

Aira – Kyushu (Japan) : JMA reported ongoing activity at both Minamidake Crater and Showa Crater (Aira Caldera’s Sakurajima volcano) during 22-29 May. Crater incandescence was observed nightly at Minamidake, and during 25-29 May at Showa; incandescence at Showa had not been visible since 5 March. The only eruptive event at Showa during this period was at 1125 on 22 May, when material was ejected 200-300 m from the crater and an ash plume rose 1.5 km above the crater rim. At 0610 on 24 May an explosion at Minamidake ejected material 300-500 m from the crater and generated an ash plume that rose 1.5 km above the crater and drifted to the SW. An eruptive event at 1327 on 25 May produced an ash plume that rose 2.3 km. On 26 May two explosions (at 0647 and 1441) and an eruptive event (1311) generated ash plumes that rose as high as 1.6 km and drifted N and S. The explosion at 1441 ejected blocks 500-700 m from the vent. An explosion at 1520 on 28 May ejected material 600-900 m from the crater and produced an ash plume that rose 2.3 km from the summit .

Bezymianny – Central Kamchatka (Russia) : KVERT reported that eruptive activity at Bezymianny was generally characterized by lava effusion, gas-and-steam emissions, lava dome incandescence, and hot avalanches that traveled down the flanks during 24-30 May. A persistent thermal anomaly was identified daily in satellite data.

Cotopaxi – Ecuador : IG reported that moderate eruptive activity continued at Cotopaxi during 23-30 May. Seismic activity was mainly characterized by long-period earthquakes and tremors associated with emissions that occurred almost daily; a total of three volcanic-tectonic earthquakes were recorded during the week. Weather clouds often hindered views, though gas-and-steam emissions were visible daily. During 23-24 May ash-and-gas emissions rose as high as 1 km above the summit and drifted W. On 26 May a period of continuous ash emissions was recorded with the plumes rising as high as 2 km above the summit and drifting NW and W. On 30 May ash plumes rose 1.2 km and drifted W; ashfall was reported in the Pastocalle parish of Latacunga canton (Cotopaxi Province).

Dukono – Halmahera : PVMBG reported that Dukono continued to erupt during 24-30 May. Daily explosions were recorded by the seismic network. White-and-gray plumes of variable densities rose as high as 450 m above the summit and drifted E.

Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 18-25 May. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 23-25 May generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l. and drifted S, SE, and E. A thermal anomaly was identified in satellite images on 24 May and ash plumes were visible drifting 75 km SE on 25 May.

Fuego – South-Central Guatemala : INSIVUMEH reported that 1-3 weak explosions per hour were recorded at Fuego on most days during 24-30 May. The explosions generated ash plumes that rose between 450-750 m above the summit. The plumes drifted as far as 10 km SE on 26 and 30 May, 10 km SE and S on 27 May, and 6 km SE and S on 29 May. Ashfall was reported in El Zapote (10 km SSE), La Rochela (8 km SSW), and San Andrés Osuna (12 km SSW) on 26 and 30 May. Minor crater incandescence was occasionally visible during some nights and early mornings. Minor lahars descended the Ceniza drainage on 25 and 28 May and a weak-to-moderate lahar descended the Santa Teresa on 29 May. Both lahars consisted of hot volcanic material, branches, tree trunks, and volcanic blocks as large as 1.5 m in diameter.

Great Sitkin c- Andreanof Islands (USA) : AVO reported that slow lava effusion continued at Great Sitkin during 23-30 May. A sequence of small low-frequency earthquakes was recorded for several hours on 23 May but did not result in any observed change in eruptive activity. Several small earthquakes were recorded daily during 24-27 May. No changes to the flow field were identified in satellite images acquired on 23, 27, or 28 May.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok continued during 24-30 May. Daily white-to-gray plumes of variable densities rose as high as 800 m above the summit and drifted E, NE, N, and NW. At 2037 on 27 May a webcam image showed an explosion of incandescent material above the summit. At 0613 on 29 May a dense gray-and-black ash plume rose 800 m above the summit and drifted NE and E.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 19-25 May and seismicity remained at elevated levels. The SW lava dome produced 236 minor lava avalanches that traveled as far as 2 km down the SW flank (upstream in the Bebeng and Boyong drainages). Morphological changes to the SW lava dome due to continuing collapses of material were evident in webcam and drone images. Based on a 17 May drone survey, the SW dome volume was an estimated 2,372,800 cubic meters and the dome in the main crater was an estimated 2,337,300 cubic meters.

Reventador – Ecuador : IG reported that the eruption at Reventador was ongoing during 23-30 May. Seismicity was characterized by 28-43 daily explosions, long-period earthquakes, harmonic tremors, and emission-related tremors. Daily gas-and-ash emissions rose as high has 1 km above the crater and drifted SW, W, NW, and NE. On most nights incandescent blocks were seen rolling 500-1,000 m down the flanks; incandescence at the crater and on the upper flanks was also periodically visible.

San Miguel – Eastern El Salvador : MARN reported that seismicity at San Miguel was detected on 23 May and remained elevated. At 1647 on 27 May an explosion generated a gas-and-ash plume that rose 700 m; seismicity decreased afterwards. Sulfur dioxide emissions were as high as 400 tons per day that same day based on measurements from an instrument located on the W flank, and then decreased to 268 and below 100 tons per day on 28 and 29 May, respectively.

Sangay – Ecuador : IG reported a high level of activity at Sangay during 23-30 May, though weather clouds sometimes prevented visual observations. There were 304-600 daily explosions recorded by the seismic network; no data was reported on 28 May. Ash plumes were seen in webcam images and reported by the Washington VAAC almost daily. On 23 May incandescent material extending 1.8 km down the SE flank was visible in webcam images. On 24 May pyroclastic flows descending 200 m were visible in between somewhat-dense weather clouds. An ash plume rose 300 m and drifted W. On 25 May ash plumes rose as high as 2 km and drifted NE and SE. Ash emissions were visible in webcam images at 1734 and were continuous for a period of time. Crater incandescence was visible overnight during 25-27 May and ash plumes that rose 500-800 m drifted SW and NW during 26-27 May. Incandescence from the lava flow on the SE flank was noted overnight during 28-29 May. The VAAC reported that at 0610 on 29 May ash plumes were visible in satellite images drifting W at 30,000 ft a.s.l., or 3.9 km above the summit, and drifting N at 40,000 ft a.s.l., or 6.9 km above the summit. Several pyroclastic flows descending the SE flank were visible in webcam images at 0615. At 1730 ashfall was reported in Cebadas Parish (Chimborazo province).

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 24-30 May. Volcano Observatory Notices for Aviation (VONAs) that described ash emissions were issued throughout the week. Daily sometimes-dense ash plumes rose as high as 1 km above the summit and drifted S, SW, W, and N.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the eruption at Sheveluch was ongoing during 18-25 May. A thermal anomaly over the active crater and Karan lava dome area was identified in satellite images all week. Intense fumarolic activity at the active crater was likely associated with dome growth.

Stromboli – Aeolian Islands (Italy) : INGV reported ongoing activity at Stromboli during 22-28 May. The Strombolian activity was centered at two vents in Area N (one each at craters N1 and N2), within the upper part of the Sciara del Fuoco, and from four vents in Area C-S (South-Central Crater) in the crater terrace. Low-intensity explosions at a rate of 3-7 per hour from Area N ejected mainly coarse material (bombs and lapilli) from N2, with mainly ash emissions from N1 as high as 80 m above the vents. Low- to medium-intensity explosions at an average rate of 2-7 per hour from the two vents in sector S2 (Area C-S) ejected a mix of coarse material and ash. During 27-28 May intense gas emissions at S1 sometimes contained coarse material. Intense spattering and occasionally weak explosions of coarse material was observed in sector C (Area C-S).

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 22-29 May and incandescence at the crater was visible nightly. Daily ash plumes from eruptive events rose as high as 1.6 km above the crater rim and drifted in multiple directions. Blocks were ejected as far as 300 m from the crater. At 2245 on 23 May an explosion generated an ash plume that rose 600 m and drifted S.

Taupo – North Island (New Zealand) : GeoNet reported that earthquake activity and ground deformation at Taupo declined during January-April and returned to background levels in May. Unrest at the volcano started in early May 2022; during the year there were just over 1,800 earthquakes located beneath the volcano along with ground deformation both on the lake floor and around the lake.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 24 May – 30 May 2023

Ahyi – Mariana Islands (USA) : Unrest at Ahyi Seamount continued during 21-30 May. Underwater events were detected by pressure sensors on Wake Island (2,270 km E) at least during 24-25 and 28-30 May. The events were possibly related to underwater explosions or earthquakes at the volcano. No activity was visible in cloudy or partly cloudy satellite images.

Etna – Sicily (Italy) : INGV reported that during 23-24 May activity at Etna was characterized by weak intra-crater explosive activity at the SE Crater and minor incandescence at Bocca Nuova Crater based on webcam images. A drone survey of the lava flows and tephra deposits emplaced during the 21 May paroxysmal eruption was conducted on 27 May. Lava flows had traveled 2.3 km, reaching 2,650 m elevation. During a field inspection on 28 May volcanologists observed gas emissions rising from Bocca Nuova and fumarolic activity at both Voragine Crater and NE Crater.

Karangetang – Sangihe Islands : Webcam images of Karangetang published in PVMBG daily reports periodically showed incandescence at Main Crater (S crater) and from material on the flanks of Main Crater during 23-30 May. Incandescence at the summit was most intense in the webcam images from 2332 on 26 May and 2304 on 29 May; the material on the flanks was brightest in the 29 May image. White gas-and-steam plumes were visible on most days rising as high as 150 m above the summit and rifting in various directions.

Nyamulagira – DR Congo : On 28 May the Observatoire Volcanologique de Goma (OVG) reported that the lava flows on Nyamulagira’s upper W flank had begun to cool and solidify. By 29 May seismicity had returned to levels similar to those recorded before the 17 May increase in activity. Lava effusion continued but was confined to the summit crater; incandescence above the crater was periodically visible.

Popocatepetl – Mexico : CENAPRED reported that during 23-30 May activity at Popocatépetl consisted of seismic tremors, very few minor and moderate explosions, near-constant emissions of steam, gas, and sometimes ash, and ejections of incandescent material. Overall activity slightly decreased during the week. A total of approximately 140 hours of high-frequency tremors of variable duration and intensity were recorded. A M 1.2 volcano-tectonic earthquake was recorded at 0340 on 24 May. Less than two hours later, at 0503, a minor explosion generated an ash plume that rose to 1 km above the summit and ejected incandescent material onto the flanks. A moderate explosion occurred at 1343. The Washington VAAC reported continuous ash emissions that rose 8.5-10.7 km (28,000-35,000 ft) a.s.l. and drifted SE. Ashfall was reported in Nealtican (21 km E), San Pedro Cholula (34 km E), San Andrés Cholula (36 km E), Tzicatlacoyan (65 km E), Tianguismanalco (22 km SE), Atlixco (25 km SE), Huaquechula (30 km SE), Ocoyucan (33 km SE), San Diego La Mesa Tochimiltzingo (39 km SE), San Juan Atzompa (71 km SE), Tehuitzingo (85 km SE), Tepexi de Rodríguez (88 km SE), Atzitzihuacán (23 km S), and Tilapa (48 km S). Emissions were sometimes continuous during the night of 24 May into the early morning of 25 May; the plumes drifted SE and were occasionally visible in webcam images. According to the VAAC ash emissions rose 7.6-8.5 km (25,000-28,000 ft) a.s.l. and drifted S, SSE, and SE. Ashfall was reported at 0045 in Atlixco, San Pedro Cholula, and the capital of Puebla. Minor ashfall was reported at 0600 in the municipality of Tetela del Volcan of Estado de Morelos. Incandescent material was ejected onto the flanks close to the crater on 25 May. The Secretary of Navy (SEMAR) conducted a drone flight during the morning of 25 May to collect information about crater activity for the Comité Científico Asesor (CCA), or Scientific Advisory Committee. During a meeting on 26 May that included the CCA, CENAPRED, CNPC, and other agencies it was shared that the drone footage of the crater showed no new lava dome, and that ash and incandescent material had significantly filled in the inner crater. Periods of continuous or nearly continuous ash emissions were recorded during 26-30 May and incandescent material was sometimes ejected short distances from the crater rim. At 1726 on 26 May a minor explosion generated steam, gas, and ash plume and ejected incandescent material. At 1926 on 29 May a minor explosion was recorded. During 26-30 May ash, steam, and gas emissions rose 5.2-7.9 km (17,000-26,000 ft) a.s.l. and drifted SE, E, and ESE according to the VAAC. Ashfall was reported in Nopalucan (87 km NE), San Pedro Cholula (34 km E), Cuautlancingo (38 km E), Puebla Capital, Amozoc (61 km E), Chietla (56 km S), Tlapanalá (39 km SE), Nopalucan (87 km NE), Tepexco (43 km S), Chila de la Sal (104 km S), Chila de las Flores (144 km SE), Tulcingo del Valle (111 km S), Atzala (53 km S), Xochiltepec (53 km SE), Yecapixtla (30 km SW), Amecameca (18 km NW), Atlixco, Atzitzihuacán (23 km S), Ayapango (21 km NW), San Pedro Benito Juárez (10-12 km SE), Acatlán de Osorio, Tlacotepec (110 km SE), Ecatzingo (15 km SW), Tochimilco (16 km SSE), Hueyapan (17 km SW), Tetela del Volcán, Tianguismanalco (22 km SE), Atlixco, Tenango del Aire (29 km NW), Huaquechula, Chautla (36 km NE), and Zacualpan (31 km SW). The eruption continued to impact residents. Air quality alerts were issued in Puebla on a few of the days during the first part of the week. According to the government of Puebla on 25 May the Ministry of Health warned residents to protect themselves from airborne ash with protective clothing and to stay inside when possible due to a reported increase in illnesses relating to ash exposure. By 26 May over one million students were able to return to classrooms.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that phreatic explosions continued at Rincón de la Vieja during 24-30 May. Moderate phreatic events at 1815 and 1830 on 24 May produced voluminous gas-and-steam plumes possibly containing some lake sediments that rose about 2.5 km above the crater rim. Aerial photos from that day showed fairly low lake water levels. The water was a milky gray color and was convecting, partly due to of subaqueous fumaroles. White deposits comprised of altered rocks blanketed the active crater from eruptive activity in recent days. A strong phreatic explosion at 1435 on 25 May produced an ash, gas, and steam plume that drifted NW. Small phreatic events were recorded at 2230 on 25 May and at 0453 and 0704 on 26 May. During a 26 May overflight the lake water level was observed to have significantly dropped compared to 24 May. Phreatic eruptions were recorded at 1357 and 2348 on 26 May and at 0221 and 0632 on 27 May. An energetic eruption at 2135 on 27 May ejected incandescent material and generated a plume mainly comprised of water vapor that rose 3.5-4 km above the crater rim. A significant lahar descended the Pénjamo River and possibly other drainages. On 29 May OVSICORI-UNA noted that the volcano was very active with frequent explosive eruptions. At 0244 an explosion ejected incandescent material and generated a lahar in the Pénjamo River.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 17 May – 23 May 2023

Aira – Kyushu (Japan) : JMA reported ongoing activity at both Minamidake Crater and Showa Crater (Aira Caldera’s Sakurajima volcano) during 15-22 May. Crater incandescence was observed nightly at Minamidake Crater. At 1429 on 17 May an eruptive event at Showa Crater produced an ash plume that rose 1.2 km above the crater rim and drifted N. An explosion from Minamidake Crater at 2027 generated an ash plume that rose 400 m and ejected large blocks 600-900 m from the crater; another eruptive event at 2051 produced an ash plume that rose as high as 1 km and drifted N. An explosion at Minamidake was recorded at 1519 on 18 May. Showa Crater sent an ash plume 1.5 km high at 1125 on 22 May.

Bulusan – Luzon (Philippines) : In a special advisory, PHIVOLCS reported that from 0500 on 21 May to 1600 on 22 May the seismic network at Bulusan recorded a total of 37 volcanic earthquakes. Out of those, 34 were volcano-tectonic earthquakes associated with rock fracturing and three were low-frequency volcanic earthquakes associated with movement of volcanic gas. Minor steam emissions from an active vent on the SE flank were occasionally visible. Ground deformation data from electronic tiltmeter stations continued to record short-term inflation of the SE flanks, first detected in December 2022.

Cotopaxi – Ecuador : IG reported that moderate eruptive activity continued at Cotopaxi during 17-23 May. Seismic activity was mainly characterized by long-period earthquakes and tremors associated with emissions that occurred almost daily; a total of six volcanic-tectonic earthquakes were recorded during the week. Emissions of steam, gas, and variable amounts of ash were observed on most days; clouds obscured views on 19 May. Weak steam-and-gas emissions that barely rose above the crater level were recorded during 17 and 20-22 May; the emissions drifted W on 22 May. Starting at 0510 on 18 May emissions of steam-and-ash rose 1-3 km above the crater and drifted N and NE; ashfall was reported in Machachi (23 km NW). During the morning of 23 May several steam-and-gas emissions with possible minor ash content were observed rising 1 km above the crater and drifting S.

Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 11-18 May. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 12-16 May generated ash plumes that rose as high as 3.5 km (11,500 ft) a.s.l. and drifted in multiple directions. A thermal anomaly was identified in satellite images during 13-14 May.

Fuego – South-Central Guatemala : INSIVUMEH reported that 1-4 weak explosions per hour were recorded at Fuego on most days during 16-23 May. The explosions generated ash plumes that rose 250-750 m above the crater; the plumes drifted S and SW during 18-20 May and as far as 10 km SW during 21-22 May. Slight incandescent at the crater was occasionally visible during dark hours a few times during the week. Very minor ashfall was reported in Morelia (9 km SW) and Panimaché (8 km SW) during 20-22 May.

Great Sitkin – Andreanof Islands (USA) : AVO reported that slow lava effusion continued at Great Sitkin during 16-23 May. Satellite data acquired on 16 May showed that the thick lava continued to expand towards the E but remained confined to the summit crater. Elevated surface temperatures were identified in satellite images during 18 and 21-23 May. Seismicity was low with some variations; five small earthquakes occurred during 19-20 May and small low-frequency earthquakes that began at 1000 on 23 May were ongoing at least through 1206.

Ibu – Halmahera : PVMBG reported that Ibu continued to erupt during 18-23 May. An average of approximately 80 eruption-related earthquakes were recorded by the seismic network during 18-22 May. White-and-gray emissions of variable densities rose as high as 1 km above the summit and drifted N, E, SE, and W. At 2021 and 2140 on 21 May dense gray ash plumes rose 600 m and 1 km above the summit, respectively, and drifted W. T

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok was ongoing during 17-23 May. Almost daily white-and-gray ash plumes rose as high as 700 m above the summit and drifted in variable directions; only white gas-and-steam plumes were visible on 19 May. A nighttime webcam image of incandescent material being ejected above the summit was captured at 1844 on 17 May.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 12-18 May and seismicity remained at elevated levels. The SW lava dome produced 182 minor lava avalanches that traveled as far as 1.8 km down the SW flank (upstream in the Bebeng and Boyong drainages) and one that traveled 500 m NW (upstream of the Senowo River). Morphological changes to the SW lava dome due to continuing collapses of material were evident in webcam and drone images.

Nevado del Ruiz – Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that the eruption at Nevado del Ruiz continued during 17-23 May and was characterized by periodic gas, steam, and ash emissions, thermal anomalies at the lava dome in Arenas Crater, and elevated seismicity. Seismic signals indicating rock-fracturing events were located 3-8 km around the Arenas Crater at depths of 1-6 km. The largest event, a M 2.1, was recorded at 0341 on 21 May and was located 2 km below the Arenas crater. Gas-and-ash emissions rose as high as 1.5 km above the crater and drifted multiple directions. A thermal anomaly was observed within the crater on 18 May.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that small phreatic eruptions periodically occurred at Rincón de la Vieja during 16-23 May. Four small events occurred during 16-17 May; the last one, recorded at 1255 on 17 May, produced a gas-and-steam plume that rose 700 m above the crater rim. Sulfur dioxide emissions were almost as high as 5,000 tonnes per day on 17 May; emissions averaged around 132 tonnes per day during the previous week. Events were recorded at 1537 on 18 May and at 0727 and 1025 on 19 May. Vigorous gas emissions were visible in the early morning of 20 May and a phreatic event occurred at 1648 that same day. At 1349 a phreatic event generated a plume mostly comprised of steam that rose 1 km above the crater rim.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 15-21 May with a daily average of 37 explosions. Gas-and-ash plumes rose as high as 2.4 km above the summit and drifted NE, E, and SE. Eight thermal anomalies originating from the lava dome in the summit crater were identified in satellite data. Seismic sensors detected 232 volcanic activity-related earthquakes, in addition to volcano-tectonic earthquakes.

Sangay – Ecuador : IG reported a high level of activity at Sangay during 17-23 May, though weather clouds sometimes prevented visual observations. Incandescent material at the crater and along the lava flow extending 1 km down the SE flank was visible nightly. On 17 May steam-and-ash emissions rose 500 m above the summit and drifted SW. On 18 May an ash plume rose 1.7 km and drifted N and SW. At 2000 on 20 May ash plumes rose 2 km above the summit and drifted to the SW. Continuous ash emissions persisted during 21-22 May, drifting W and SW. Ashfall during 20-22 May was reported in Chauzan, Guamote, Tixán, Palmira, Cebadas, and Alausí cantons in the Province of Chimborazo.

Santa Maria – Southwestern Guatemala : INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 16-23 May. Effusion from the Caliente dome complex fed lava flows that descended the San Isidro and Zanjón Seco drainages on the W and SW flanks; the main lava flow was 4.3 km long and remained active. Avalanches of material from the growing dome and occasional explosions descended all sides of the dome and avalanches from the lava flow descended the S and SW flanks. Explosions generated gas, steam, and ash plumes that drifted S and SW on a few days. Incandescence from the dome and lava flows was visible during the nights and early mornings. An average of 40 explosions per day were recorded during 21-22 May, generating ash plumes that rose up to 1 km above the dome and drifted SW.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 17-23 May and several Volcano Observatory Notices for Aviation (VONAs) describing ash emissions were issued during the week. Daily white-to-gray ash plumes that were sometimes dense rose 200-800 m above the summit and drifted in multiple directions. VONAs were issued as follows: 0501, 0646, and 0919 on 17 May; 0517 and 0822 on 18 May; 0547, 0911, and 0936 on 19 May; 0545, 0733, 0742, and 1054 on 20 May.

Semisopochnoi – Aleutian Islands (USA) : On 17 May AVO reported that eruptive activity at Semisopochnoi had declined during the previous week, though seismicity remained slightly elevated and low-level steaming continued from Mount Young. Ash emissions had last occurred on 5 May leaving minor deposits on the NW flank of Mount Young’s N crater. Intense gas emissions were periodically visible in webcam images during 17-18 and 20-21 May. On 22 May a weak sulfur dioxide signal was detected, suggestive of low-level degassing.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the eruption at Sheveluch was ongoing during 11-18 May. A thermal anomaly over the active crater and Karan lava dome area was identified in satellite images all week. Intense fumarolic activity at the active crater was likely associated with dome growth. Plumes of ash, originally deposited during the 10-13 April eruption and resuspended by strong winds, were visible in satellite images drifting 400 km SE during 14-15 May.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 15-22 May. Incandescence was visible nightly, and seismicity remained elevated during 15-19 May. On 16 May an ash plume rose 1.8 km above the crater rim and caused ashfall in Toshima village (3.5 km SSW). On 17 May, an ash plume rose to 1.1 km and drifted NW. Four eruptive events were observed during 21-23 May. On 21 May an eruptive event ejected volcanic blocks up to 200 m from the crater and produced an ash plume that rose 1.8 km above the crater and drifted E. On 22 May an ash plume rose to 1 km above the crater and drifted SE. Two eruptive events on 23 May generated ash plumes that rose 600 m above the crater and drifted SE and S.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 17 May – 23 May 2023

Ahyi – Mariana Islands (USA) : The U.S. Geological Survey reported that unrest at Ahyi Seamount was again detected, after activity paused in early April. Signals consistent with eruptive activity were recorded by underwater pressure sensors on Wake Island, 2,270 km E, beginning at about 2210 on 21 May and were continuing. A plume of discolored sea water was observed above the area of the vent in a satellite image on 22 May.

Etna – Sicily (Italy) : Strong explosive eruptions were reported at Etna by INGV starting on 18 May after continuous degassing and moderate seismicity over the previous few days, with significant Strombolian activity and a paroxysmal event at SE Crater on 21 May. Views were often obscured by persistent weather cloud cover. Strombolian activity from SE Crater at 0456 on 18 May was seen in webcam images from the camera located at Montagnola. A seismic swarm in the summit area at 1644 was immediately followed by ground deformation recorded at the Punta Lucia and Pizzi Deneri summit stations. At 1656 weak intra-crater Strombolian activity at SE Crater was observed in images taken by the INGV thermal camera at La Montagnola (3 km S). Explosive activity from Bocca Nuova crater starting at 1700 was visible in thermal images from the Bronte (13 km WNW) webcam, concurrent with infrasonic signals. The activity likely persisted for a few hours based on satellite images; weather conditions prevented confirmation with webcams. Tremor fluctuated and by 0927 on 19 May levels had begun to decrease. Intermittent explosive activity persisted at SE Crater during 19-20 May, with pulsating gas emissions rising from the crater. A sharp increase in volcanic tremors at 0720 on 21 May was a precursor to significant tall lava fountaining during 0730-1140, with ash plumes that rose to 10 km and drifted SW, S, and SE. At 0937 INGV field personnel observed ash and lapilli fall on the SW flank and ashfall in Adrano at 560 m elevation. Lava flows from SE Crater descended the W part of the Valle del Bove as far as 1.9 km E and the S flank as far as 2 km. Satellite data showed a large sulfur dioxide plume drifting E. Weather clouds prevented views of the activity. Tremor levels sharply decreased starting at 1135 and had stabilized by 1200. Ashfall was also reported in Catania and Aci Castello. According to news reports the ashfall caused the Catania-Fontanarossa Airport in Sicily to close until 0900 on 22 May. The runway had been covered in ash and at least 68 flights to and from the airport were cancelled.

Karangetang – Sangihe Islands : PVMBG reported that activity at Karangetang had intensified in May, leading to a change in the Alert Level status. During 1-17 May white gas-and-steam plumes were sometimes dense and rose as high as 250 m above the summit, slightly higher than the 200 m maximum height noted in April. Incandescence at North Crater was visible at night 10-25 m above the lava dome. Incandescence also emanated from Main Crater though the glow was less intense, reaching about 10 m above the dome. Sounds of falling rocks at Main Crater were heard on 15 May, the seismic network recorded 32 rockfall events in the crater on 17 May, and rock avalanches on 18 May traveled as far as 1.5 km down the SW and S flanks accompanied by rumbling sounds. On 19 May the Alert Level was raised to 3 (on a scale of 1-4) and the public was warned to stay 2.5 km away from the craters on the S and SW flanks and 1.5 km away on the other flanks. A webcam image from 2025 on 19 May showed incandescent material traveling down the flanks. On 21 May white gas-and-steam plumes rose 400 m above the summit.

Nyamulagira – DR Congo : The Observatoire Volcanologique de Goma (OVG) reported that lava continued to erupt from vents in Nyamulagira’s summit crater during 17-23 May. Lava flows began moving into the N and NW parts of the crater beginning on 9 May, towards the low point of the crater rim. Intense incandescence from the summit was visible from Goma (27 km S) during the evenings of 17 and 19 May. Satellite images showed a notable sulfur dioxide plume drifting NW and W during 19-20 May. Drone footage acquired on 20 May captured images of narrow lava flows traveling about 100 m down the W flank. Intense incandescence emanating from the summit was again visible from Goma at around 1830. Data from the Rumangabo seismic station indicated a downward trend in activity during 17-20 May and a significant decrease during 20-21 May. Though weather clouds were dense over the summit, hot lava on the NW flank was visible in a 22 May Sentinel-2 infrared (SWIR) image.

Popocatepetl – Mexico : CENAPRED reported that activity at Popocatépetl intensified during 16-23 May after recent activity characterized by the formation of small to medium lava domes on the summit crater floor and their subsequent destruction. There were 154-168 daily steam, gas, and ash emissions and minor-to-moderate explosions during 16-19 May. Periods of high-frequency tremor lasted more than 12 hours during 16-17 May and more than 10 hours during 17-18 May. Minor ashfall was reported on 18 May in the municipalities of Atlixco (25 km SE) and Cholula (35 km E), Puebla. Six volcano-tectonic earthquakes with magnitudes as high as 1.8 were recorded along with over 2 hours of high-frequency tremor on 19 May. Residents of Tétela del Volcán (18 km SW), Morelos, noted minor ashfall. According to the Washington VAAC ash plumes rose 6.7-7 km (22,000-23,000 ft) a.s.l., or 1.3-1.6 km above the summit, during 16-19 May. A period of high-frequency tremor that began at around 1800 on 19 May and lasted about 10 hours until about 0400 on 20 May was accompanied by steam, gas, and ash plumes that drifted NNW and continuous ejection of incandescent tephra onto the flanks as far as 1.5 km from the crater. On 20 May the Benito Juárez International Airport closed during about 0430-1000 and the Felipe Ángeles International Airport closed during 0600-1100 in order to clear ash from runways. Ash fell in multiple areas downwind including in the municipalities of Venustiano Carranza (66 km NW), Gustavo A. Madero (73 km NW), Azcapotzalco (78 km NW), Tlalpan (62 km NW), Iztapalapa (58 km NW), Amecameca (18 km NW), Ayapango (21 km NW), Ozumba (18 km W), Ecatzingo (15 km SW), Atlautla (16 km W), Valle de Chalco (44 km NW), La Paz (50 km NW), Chalco (38 km NW), Nezahualcóyotl (56 km NW), Temamatla (32 km NW), Tenango del Aire (29 km NW), Tlalmanalco (27 km NW), Juchitepec (28 km NW), Cocotitlán (34 km NW), and Tepetlixpa (21 km W). Ashfall in Puebla municipalities included Huejotzingo (28 km NE), Nealtican (21 km E), Chignahuapan (108 km NE), Puebla Capital (44 km E), San Martín Texmelucan (35 km NE), and San Felipe Teotlalcingo (26 km NE). Additional explosions were recorded at 1047, 1247, 1454, 2136, 2238, and 2253 on 20 May. Almost 19 hours of high-frequency tremor recorded during 20-21 May was accompanied by continuous emissions of steam, gas, and ash and occasional ejections of incandescent material short distances onto the flanks. The Washington VAAC reported that activity intensified at 1453 on 20 May as a large, dense ash plume was visible in webcam images. By 1551 the ash plume was visible in satellite images rising to 8.2 km (27,000 ft) a.s.l., or 2.8 km above the summit. By 2041 the dense ash plume had risen to 9.1 km (30,000 ft) a.s.l., or 3.7 km above the summit, and drifted ENE far over the Gulf of Mexico. The plume rose as high as 9.7 km (32,000 ft) a.s.l., or 4.3 km above the summit by 2136 and remained at that altitude at least through 0341 on 21 May as it fanned out to the NE and ENE. By 0951 on 21 May ash plumes were rising to 9.1 km and at 1436 plumes were reaching 8.5 km (28,000 ft) a.s.l., or 3.1 km above the summit. Satellite images showed a large dense ash plume drifting 388 km NE over the Bay of Campeche, but emissions were most dense within 65 km of the summit. Webcam images showed that continuing dense ash emissions. According to CENAPRED the Scientific Advisory Committee of the Popocatépetl Volcano announced on 21 May that the Alert Level was raised from Yellow, Phase 2, to Yellow, Phase 3, the highest of the three sub-phases based on the intensifying activity over the previous few days. The National Coordination of Civil Protection (CNPC) announced actions to be implemented by the state civil protection units including preparing evacuation routes and evacuation teams and shelters. Ashfall was reported in Puebla state, in the municipalities of San Andrés Cholula (36 km E), San Pedro Cholula (34 km E), Cuautlancingo (38 km E), Amozoc (61 km E), Puebla Capital (44 km E), Zacatlán (121 km NE), Tetela de Ocampo (121 km NE), and Chignahuapan (108 km NE). The Hermanos Serdán International Airport, in Puebla (30 km NE), closed at 2300 on 21 May until 0700 on 22 May according to Gobierno de Puebla. High-frequency tremor was almost constant for over 23 hours during 21-22 May. Steam, gas, and ash emissions were continuous with occasional ejections of incandescent material short distances onto the flanks. Explosions occurred at 1355 on 21 May and 0533 on 22 May. According to the Washington VAAC satellite images acquired at 0236, 0821, 1421, and 1936 revealed continuing ash emissions to 3.7 km above the summit, drifting E and ENE. An accompanying very large sulfur dioxide plume drifted as far as Cancun, 1,295 km E. Ashfall occurred in the municipalities of San Andrés Cholula (36 km E), San Pedro Cholula (34 km E), Cuautlancingo (38 km E), Amozoc (61 km E), Zacatlán (121 km NE), Tetela de Ocampo (121 km NE), San Nicolás de los Ranchos (15 km NE), Palmar de Bravo (115 km SE), Tepeaca (76 km E), in Izúcar de Matamoros (51 km S), Epatlán (51 km SE), Teopantlán (52 km SE), Tlapacoya (144 km NE), Huatlatlauca Chignahuapan (72 km SE), and in the Puebla capital, in the state of Puebla. Ash also fell in Juchitepec (28 km W), State of Mexico, Hueyapan (17 km SW), Locality of Xochitepec (municipality of Jolalpan) (68 km SW), in Morelos, and in the capital of the state of Tlaxcala (50 km NE). At 1651 on 22 May the Hermanos Serdán International Airport suspended operations due to ash on the runway. Tremor remained nearly continuous (more than 20 hours) during 22-23 May. Ongoing steam, gas, and ash emissions drifted NE, and occasional ejections of incandescent material short distances onto the flanks. Ash fell in the municipalities of Nealtican, Tianguismanalco, Atlixco, San Diego la Mesa, Huaquechula, and Atzizihuacán, State of Puebla. Ash plumes rose as high as 3.7 km above the summit and drifted E according to the Washington VAAC.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 10 May – 16 May 2023

Aira – Kyushu (Japan) : JMA reported ongoing activity at both Minamidake Crater and Showa Crater (Aira Caldera’s Sakurajima volcano) during 8-15 May. Crater incandescence was observed nightly at Minamidake Crater. On 8 May sulfur dioxide emissions were extremely high at 3,900 tons per day. At 1315 on 9 May an explosion at Minamidake generated an ash plume that rose 1.2 km above the crater rim and drifted SW, and ejected blocks 1.1 km from the vent. Eruptive events at 1527, 1724, and 1817 on 11 May produced ash plumes that rose as high as 1.3 km and drifted NW and W. At Showa Crater eruptive events recorded at 1009, 1303, and 1401 on 8 May, at 0550, 0726, 2204, and 2321 on 11 May, at 1831 on 12 May, and at 0859 on 14 May produced ash plumes that rose as high as 1.7 km above the crater rim and drifted in multiple directions. Sulfur dioxide emissions were somewhat high on 12 May, averaging 1,800 tons per day.

Bezymianny – Central Kamchatka (Russia) : KVERT reported that activity at Bezymianny was generally characterized by gas-and-steam emissions, incandescence at the lava dome, and hot avalanches from the lava dome during 4-11 May. A daily thermal anomaly was identified daily in satellite images.

Cotopaxi – Ecuador : IG reported that moderate eruptive activity continued at Cotopaxi during 9-16 May. Daily seismic activity was characterized by long-period earthquakes and tremors indicating emissions; a few volcano-tectonic earthquakes were recorded during the week. Emissions of steam, gas, and variable amounts of ash were observed on most days. During 9-10 May plumes with moderate amounts of ash rose 2-3 km above the crater rim and drifted SW, N, and NE. Ashfall was reported in areas to the SW, including San Joaquín and San Agustín de Callo. On 11 May gas-and-steam plumes rose 700 m above the summit and drifted to the E and SE. Emissions with moderate ash content on 12 May rose 1-2 km above the crater rim and drifted to the SE; later that day ash plumes rose 700 m. On 13 May steam-and-gas emissions with low or no ash content rose 900 m above the summit and drifted S, and gas-and-ash plumes rose 800 m and drifted SE. On 15 May steam-and-ash plumes rose 400 m and drifted W and SW. Weather clouds often prevented views during 14-16 May.

Dukono – Halmahera : PVMBG reported that the eruption at Dukono was ongoing during 10-15 May. Daily dense white-and-gray ash plumes rose as high as 700 m above the summit and drifted E and N.

Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 4-11 May. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 4, 6-7, and 9-10 May generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted E. A thermal anomaly was identified in satellite images on 9 May.

Etna – Sicily (Italy) : INGV reported that an explosion at Etna’s SE Crater occurred at 0839 on 14 May and produced an ash emission that rapidly dispersed around the summit area. No significant variations in the seismic data were associated with the explosion.

Great Sitkin – Andreanof Islands (USA) : AVO reported that lava likely continued to erupt at the summit of Great Sitkin during 9-16 May. Satellite data acquired on 11 May showed that the thick lava continued to expand towards the E but remained confined to the summit crater. Seismicity was low. Nothing significant was seen in satellite and webcam images during most of the week due to persistent weather clouds obscuring views.

Krakatau – Sunda Strait : During 10-13 May PVMBG reported that white-and-gray and white-and-brown ash plumes generally rose as high as 200 m above Anak Krakatau’s summit and drifted SW and NW, though a few Volcano Observatory Notices for Aviation (VONAs) described higher plumes. At 1241 on 11 May a gray ash plume rose 1 km above summit and drifted SW. At 0920 on 12 May a dense gray ash plume rose 2.5 km and drifted SW. At 2320 a dense gray ash plume rose 1.5 km and drifted SW. An accompanying webcam image showed incandescent material being ejected above the vent. At 0710 on 13 May a dense gray ash plume rose 2 km and drifted SW.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok was ongoing during 9-16 May. Almost daily white-and-gray ash plumes generally rose as high as 500 m above the summit and drifted in variable directions. At 0632 on 11 May a white-to-gray ash plume rose 500 m and drifted SW. At 0645 and 0957 on 11 May white-to-gray ash plumes rose 400-600 m and drifted E and SE, respectively. Nighttime webcam images of incandescent material being ejected above the summit were posted in daily reports during 10-13 May.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 5-11 May and seismicity remained at elevated levels. The SW lava dome produced 106 lava avalanches that traveled as far as 1.8 km down the SW flank (upstream in the Bebeng drainages). Morphological changes to the SW lava dome due to continuing collapses of material were evident in webcam images.

Nyamulagira – DR Congo : The Observatoire Volcanologique de Goma (OVG) reported that the lava lake in Nyamulagira’s summit crater continued to be active during 30 April-6 May. A Sentinel satellite image from 7 May showed active lava flows traveling towards the NW part of the crater. Another image on 12 May showed active flows along the NE margin of the dark and cooler 7 May flows. Weather clouds and possible volcanic emissions obscured parts of the crater.

Popocatepetl – Mexico : CENAPRED reported that there were 127-281 daily steam, gas, and ash emissions and minor-to-moderate explosions recorded at Popocatépetl during 9-16 May. Plumes mostly drifted SE, ESE, and ENE. On 9 May minor explosions were recorded at 1141, 2009, and 2310, and on 10 May moderate explosions were recorded at 0152 and 0316. Ashfall was reported in Tlalmanalco (30 km NW) and Tetela del Volcán (20 km SW) in Morelos during 9-10 May. On 11 May minor explosions were recorded at 0135, 0215, and 1621, while moderate explosions were recorded at 0526, 0811, 0838, 1601, and 1646. Minor explosions occurred at 1318 and 1452 on 12 May. On 13 May minor explosions occurred at 0012, 0805, and 2146, and a moderate explosion occurred at 1012. Ashfall was reported in the municipalities of Nealtican (20 km E), Huejotzingo (21 km E), and Domingo Arenas (20 km NE). On 14 May minor explosions were recorded at 0605, 0711, 0831, 1413, 1439, and 2312; moderate explosions were recorded at 1253, 1444, 1608, and 1941. On 15 May the network detected minor explosions at 0033 and 0051, and moderate explosions at 0352, 0512, 0617, 0852, 1051, 1232, and 1613. Minor amounts of ash fell in the municipalities of Puebla (43 km E) and Atlixco (24 km SE) and moderate amounts fell in municipalities near the volcano to the S. Weather clouds prevented views on 16 May. According to the Washington VAAC daily ash plumes were identified in satellite images rising 6.1-7.3 km (20,000-24,000 ft) a.s.l. (0.7-1.9 km above the crater rim) and drifting E and SE.

Reventador – Ecuador : IG reported that the eruption at Reventador was ongoing during 10-16 May. Seismicity was characterized by explosions, long-period earthquakes, harmonic tremors, and emission-related tremors. Steam, gas, and ash plumes were observed in some webcam images, though weather conditions occasionally obscured views. Ash emissions on 12 May rose 500 m above the crater rim and drifted N. On 14 May a steam-and-ash plume rose 250 m and drifted NE. On 16 May an ash plume rose as high as 1 km above the crater and drifted W and SW. Incandescence at the crater was visible at night during 10-12 and 16 May, and incandescent blocks rolled 200-700 m down the flanks.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that periodic phreatic eruptions occurred at Rincón de la Vieja during 9-16 May. Phreatic events recorded at 1945 on 9 May, at 1419 on 10 May, and at 1100 on 11 May produced plumes that rose less than 1.5 km above the crater rim. Additional phreatic activity were recorded at 2232 on 11 May, and at both 2332 and 2338 on 12 May, though it was not known if emissions were generated. A short-lived explosive event at 0258 on 14 May ejected material onto the N flank and caused lahars to descend the Penjamo, Azul, and Azufrado rivers. Phreatic events at 1155 and 1748 that same day produced emissions that rose 500 m and 1.5 km above the crater rim, respectively. Gas emissions were occasionally visible during 15-16 May.

Sangay – Ecuador : IG reported a high level of activity at Sangay during 9-16 May, though weather clouds prevented visual observations during most of the week. Ash plumes rose 500 m and drifted SW on 9 May. A webcam image from 1833 on 14 May showed lava flowing 500 m down the SE flank.

Santa Maria – Southwestern Guatemala : INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 10-16 May. Effusion from the Caliente dome complex fed lava flows that descended the San Isidro and Zanjón Seco drainages on the W and SW flanks; the main lava flow was 4.3 km long and remained active. Daily weak-to-moderate explosions generated gas, steam, and ash plumes that generally rose up to 800 m above the crater and drifted SE, S, SW, and W. Explosions were sometimes accompanied by block-and-ash flows that descended multiple flanks of the dome. Incandescence from the dome and lava flows was visible during the nights and early mornings. An average of 40 explosions per day were recorded during 9-10 and 13-14 May, generating ash plumes that rose up to 1 km above the dome and drifted S and SW. Ashfall was reported in Fincas El Patrocinio, El Faro (7 km S), Las Marías (10 km S), and others nearby on 10 May.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 10-16 May and a few Volcano Observatory Notices for Aviation (VONAs) describing ash emissions were issued during the week. White-to-gray ash plumes that were sometimes dense rose 500-700 m above the summit and drifted S, SW, W, and N at 1115 on 10 May, at 0725 and 0830 on 12 May, at 0858, 1010, and 1241 on 13 May, at 0523 and 1656 on 14 May, and at 0757 on 16 May.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level unrest continued at Semisopochnoi during 9-16 May. Weather clouds mostly obscured satellite and webcam views. Volcanic tremor was detected during 9-10 May; there was no evidence of explosive or earthquake activity in the geophysics data during the rest of the week.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the ongoing eruption at Sheveluch was generally characterized by occasional explosions, continuing lava-dome growth, incandescence, and strong fumarolic activity during 4-11 May. A thermal anomaly over the active crater and Karan lava dome area was identified in satellite images all week. Intense fumarolic activity was likely associated with dome growth. During 8-9 May ash from pyroclastic flow deposits on the SE flank were resuspended by winds and blown 60 km W based on satellite images.

St. Helens – Washington : USGS reported that at 2045 on 14 May a debris flow in Mount St. Helens’ South Coldwater Creek destroyed a Highway SR 504 bridge, cutting off access and power to Johnston Ridge Observatory. While the loss of power interrupted a major telemetry hub, other stations remined operational and continued to provide data; the debris flow was recorded in seismic data from nearby stations. The source material in the flow originated from the climactic 1980 debris avalanche and eruption of Mount St. Helens. According to a news article at least 11 people had to spend the night at the Johnston Ridge Observatory and were airlifted out the next day. Officials noted that the highway will be closed for an indefinite amount of time.

Stromboli – Aeolian Islands (Italy) : INGV reported ongoing Strombolian activity at Stromboli during 8-14 May. Activity was centered at two vents (one each at craters N1 and N2) in Area N, within the upper part of the Sciara del Fuoco, and from three vents in the Area C-S (South-Central Crater area) in the crater terrace area. Explosions at the N1 and N2 craters in Area N were low intensity and ejected coarse material (bombs and lapilli), sometimes mixed with ash at N1, as high as 80 m at a rate of 4-9 explosions per hour. Medium- to high-intensity explosions at the two vents in sector S2 (Area C-S) ejected ash sometimes mixed with coarse material at an average rate of 5-8 explosions per hour. Low-intensity gas explosions occurred at S1 in Area C-S. No significant activity was identified in Sector C in Area C-S.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 8-15 May and crater incandescence was reported nightly. Explosions recorded at 0701, 1200, and 2330 on 8 May produced ash plumes that rose as high as 1 km above the crater rim and mainly drifted SE. Explosions were also recorded at 1358 and 1648, though characteristics of associated emissions were unknown. Eruptive events at 2001 on 8 May, 1753 on 9 May, 0405, 0647, and 1236 on 11 May, and 1919 on 13 May generated ash plumes that rose as high as 1.3 km and generally drifted S, SW, and N.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 10 May – 16 May 2023

Fuego – South-Central Guatemala : INSIVUMEH reported that a range of 1-7 weak explosions per hour were recorded at Fuego during 10-16 May. The explosions generated ash plumes that rose to a maximum height of 850 m above the crater and drifted up to 12 km E, SE, S, and SW. Occasional weak avalanches of material were visible near the crater. During 9-10 May wind entrained loose ash that was deposited along the Ceniza, Las Lajas, and Seca drainages. On 12 May a minor lahar descended the Ceniza drainage, carrying branches, tree trunks, and volcanic blocks up to 1.5 m in diameter. Minor incandescent over the crater was visible overnight during 12-13 and 15-16 May. Wind entrained ash deposits during 15-16 May causing localized “curtains” of ash.

Kita-Ioto – Volcano Islands : Japan Coast Guard reported that a small area of bluish-white discolored water above Funka Asane, a submarine vent 4-5 km NW of Kita-Ioto, was visible on 11 May. This was the first time discolored water was seen over the vent in about two years.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 3 May – 9 May 2023

Aira – Kyushu (Japan) : JMA reported that Minamidake Crater and Showa Crater (Aira Caldera’s Sakurajima volcano) remained active during 1-8 May. Crater incandescence was observed nightly at Minamidake Crater. Three explosions at Minamidake during 2-3 May produced small shock waves and ash plumes. The explosion at 0422 on 2 May generated an ash plume that rose 1.8 km above the crater rim and drifted SW, and ejected blocks 500-700 m from the vent. The explosion at 0241 on 3 May produced an ash plume that rose 800 m and ejected blocks to 500-700 m from the vent. Later that morning, at 1025, an explosion produced an ash plume that rose 500 m and drifted W. An ash plume from an eruptive event at 2337 on 7 May rose 1 km. At Showa Crater very small eruptive events were recorded during 1-5 May, and three eruptive events on 8 May produced ash plumes that rose as high as 1.2 km above the crater rim and drifted S and SW.

Cotopaxi – Ecuador : IG reported that moderate eruptive activity continued at Cotopaxi during 2-9 May. Seismic activity was largely dominated by long-period earthquakes, tremors indicating emissions, and a few volcano-tectonic earthquakes. Emissions of steam, gas, and variable amounts of ash were observed daily. During 2-3 May minor ash plumes rose less than 200 m above the crater rim and drifted W. On 4 May ash plumes rose as high as 1.5 km above the crater rim and drifted SW and NW, drifting as far as the province of Manabí. On 5 May several emissions with low ash content rose as high as 300 m and drifted SW. On 7 May ash plumes rose as high as 1.1 km above the crater rim and drifted W and SW, causing minor ashfall in areas downwind including Mulaló. On 8 May a seismic station recorded a small secondary lahar. Several steam-and-gas emissions were visible during 8-9 May.

Ebeko – Paramushir Island (Russia) : KVERT reported that moderate activity at Ebeko was ongoing during 27 April-4 May. A thermal anomaly was identified in satellite images on 3 May. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions during 3-4 May generated ash plumes that rose as high as 4 km (13,100 ft) a.s.l. and drifted SW and E.

Etna – Sicily (Italy) : INGV reported that a sudden explosion at Etna’s SE Crater occurred at 2325 on 6 May and produced a diffuse ash emission that rapidly dispersed around the crater area. The Aviation Color Code was raised to Yellow at 2358 and then lowered back to Green at 1148 on 7 May. Neither seismic nor infrasound data recorded changes associated with the explosion.

Great Sitkin – Andreanof Islands (USA) : AVO reported that lava continued to erupt at the summit of Great Sitkin during 2-9 May. Satellite data acquired on 5 May showed that the thick lava continued to expand towards the E but remained confined to the summit crater. Seismicity was low, and during 7-8 May only a few small events were detected. Nothing significant was seen in satellite and webcam images during most of the week, though sometimes weather clouds obscured views.

Ibu – Halmahera : PVMBG reported that the eruption at Ibu continued during 3-9 May. White-and-gray plumes of variable densities rose as high as 800 m above the summit and drifted in several directions.

Lewotolok – Lembata Island : PVMBG reported that the eruption at Lewotolok was ongoing during 3-9 May. Daily white-and-gray or dark gray ash plumes rose as high as 800 m above the summit and drifted NW, W, and SW. Webcam images of incandescent material being ejected above the summit were posted in daily reports during 7-8 May.

Merapi – Central Java : BPPTKG reported that the eruption at Merapi (on Java) continued during 28 April-4 May and seismicity remained at elevated levels. The SW lava dome produced 190 lava avalanches that traveled as far as 2.5 km down the SW flank (upstream in the Bebeng and Boyong drainages). One pyroclastic flow traveled 2.5 km down the Bebeng drainage. Morphological changes to the SW lava dome due to continuing collapses of material were evident in webcam images.

Raung – Eastern Java : PVMBG reported that during 1-30 April white steam-and-gas plumes of moderate intensity rose as high as 200 m above Raung’s summit. Monitoring data along with visual observations did not suggest elevated levels of activity.

Rincon de la Vieja – Costa Rica : OVSICORI-UNA reported that phreatic eruptions occurred a few times at Rincón de la Vieja during 3-9 May. Phreatic events were recorded at 0100 and 2254 on 3 May, and at 1434 on 8 May, though darkness or weather clouds prevented visual confirmation. A small phreatic event occurred at 1847 on 6 May.

Sabancaya – Peru : Instituto Geofísico del Perú (IGP) reported moderate levels of activity at Sabancaya during 1-7 May with a daily average of 23 explosions. Gas-and-ash plumes rose as high as 2 km above the summit and drifted N, E, and SE. Three thermal anomalies originating from the lava dome in the summit crater were identified in satellite data.

Santa Maria – Southwestern Guatemala : INSIVUMEH reported that the eruption at Santa María’s Santiaguito lava-dome complex continued during 2-9 May. Effusion from the Caliente dome complex fed lava flows that descended the San Isidro and Zanjón Seco drainages on the W and SW flanks; the main lava flow was 4.3 km long and remained active. Daily weak-to-moderate explosions generated ash-and-steam plumes that generally rose as high as 800 m and drifted SW. The explosions were also accompanied by block-and-ash flows that descended multiple flanks of the dome. Incandescence from the dome and the lava flows was visible each morning and night. Avalanches of material from the lava-flow front and margins caused ash plumes around the flanks. Activity during 5-6 May was characterized by high levels of extrusive and explosive activity; 40 explosions were recorded, producing ash plumes that rose 3.5 km above the dome and drifted SW. Ashfall was reported in San Marcos Palajunoj (8 km SW), Loma Linda (7 km W), and other nearby communities. During 6-7 May quiet rumbling sounds were heard on nearby farms. Residents were warned to stay 6 km away from the lava-dome complex.

Semeru – Eastern Java : PVMBG reported that the eruption at Semeru continued during 3-9 May and a few Volcano Observatory Notices for Aviation (VONAs) describing ash emissions were issued during the week. At 0546 on 4 May a dense white-to-gray ash plume rose 1 km above the summit and drifted S. At 0521 on 5 May and at both 0839 and 2315 on 7 May medium-to-dense white-to-gray ash plumes rose 600 m and drifted S, SW, and W. At 0809 and 0922 white-to-gray ash plumes rose 300-600 m and drifted S and W.

Semisopochnoi – Aleutian Islands (USA) : AVO reported that low-level unrest continued at Semisopochnoi during 2-9 May, though it was seismically quiet for the most part, with only occasional small earthquakes. Cloudy weather often obscured satellite views. Steam emissions from the N crater of Mount Young were visible in partially clear webcam images during 3-6 May. A new NW-flank ash deposit was present on fresh snow; no signs of explosive activity were seen in geophysical data.

Sheveluch – Central Kamchatka (Russia) : KVERT reported that the ongoing eruption at Sheveluch was generally characterized by occasional explosions, continuing lava-dome growth, incandescence, and strong fumarolic activity during 27 April-4 May. A thermal anomaly was identified in satellite images all week. Satellite data showed a gas-and-steam plume with some ash drifting 60 km SE at 2350 on 29 April. The Kamchatka Volcanological Station posted pictures and video taken during a 4 May overflight that showed three active fumaroles on the dome. Low weather clouds obscured parts of the dome area. Photos showed tephra-fall on surrounding lakes, rivers, and forests, and it was noted that lahar deposits blocked a road W of the volcano.

Suwanosejima – Ryukyu Islands (Japan) : JMA reported that the eruption at Suwanosejima’s Ontake Crater continued during 1-8 May, and crater incandescence was reported nightly. No explosions were recorded during 1-5 May, but eruptive activity produced periodic ash plumes that rose as high as 1.6 km above the crater rim and ejected blocks 300 m from the crater. Explosions at 0701, 1200, 2001, and 2330 on 8 May generated ash plumes that rose as high as 1 km and drifted SE and SW. Explosions also occurred at 1358 and 1648, though no associated emissions were reported.