Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 15 February-21 February 2017 – cont.

Nevado del Ruiz | Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 14-20 February seismicity at Nevado del Ruiz continued to indicate unrest. Earthquakes were located at depths of 1.1-1.7 km, in areas N, NE, SE, and SW of the volcano, but mainly beneath Arenas Crater. The largest event was a local M 1.4. Signals indicating fracturing rock increased in both size and number as compared to the previous week. Significant amounts of water vapour and gas continued to be emitted. Gas, steam, and ash plumes rose 1.2 km above the crater rim on 18 February and drifted NE, SE, and SW. Thermal anomalies were identified by the MIROVA system during 14, 16-17, and 19-20 February. The Alert Level remained at III (Yellow; the second lowest level on a four-colour scale).

Reventador | Ecuador : During 15-21 February IG reported a high level of seismic activity including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions at Reventador. Although cloud cover often prevented visual observations, activity was noted almost daily. Minor ashfall was reported on 15 February, and the next morning crater incandescence was visible. During 17-19 and 21 February steam, gas, and ash plumes rose 1-2 km above the crater rim and mainly drifted S and W. “Gunshot” sounds were heard on 18 February.

Sabancaya | Peru : Based on webcam views, satellite images, and seismic data the Buenos Aires VAAC reported that during 14-21 February sporadic gas-and-ash puffs rose from Sabancaya, and during 16-17 and 20 February rose to altitudes of 7.3-8.2 km (24,000-27,000 ft) a.s.l. Weather clouds often hindered observations of the volcano.

Santa Maria | Guatemala : INSIVUMEH reported that during 16-17, 19, and 20-21 February a few explosions at Santa María’s Santiaguito lava-dome complex generated ash plumes that rose 700 m above the complex and drifted SW. Minor ashfall was reported in La Florida (5 km S) on 19 February and in Monte Claro (S) during 20-21 February.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 10-17 February lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed a daily thermal anomaly over the dome. The Aviation Colour Code remained at Orange.

Sinabung | Indonesia : Based on PVMBG observations, satellite and webcam images, and wind data, the Darwin VAAC reported that during 16-18 and 20-21 February ash plumes from Sinabung rose to altitudes of 3-4.3 km (10,000-14,000 ft) a.s.l. and drifted W, SW, and S.

Turrialba | Costa Rica : OVSICORI-UNA reported that during 15-16 February high-amplitude tremor at Turrialba remained constant, and sporadic gas emissions with minor amounts of ash drifted S and E. Occasional ballistics were ejected from the crater. During 16-17 February sporadic gas emissions with low ash content rose no higher than 300 m and drifted NW and SW. Tremor amplitude had decreased to moderate levels. Similar emissions were observed during 20-21 February, although they drifted NW and NE.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 15 February-21 February 2017

Bagana | Bougainville (Papua New Guinea) : Based on analyses of satellite imagery, the Darwin VAAC reported that during 16 and 18-20 February ash plumes from Bagana rose to altitudes of 2.4-3.4 km (8,000-11,000 ft) a.s.l. and drifted SSE, S, and SW. Ash plumes drifted as far as 85 km during 19-20 February.

Bogoslof | Fox Islands (USA) : AVO reported that during 15-16 February cloud cover prevented satellite views of Bogoslof; no other data indicated eruptive activity. At 0955 on 17 February seismic data indicated the beginning of an explosive event, prompting AVO to raise the Aviation Colour Code (ACC) to Red and the Volcano Alert Level (VAL) to Warning. Individual pulses of seismicity was recorded until 1140, and then afterwards seismicity was low. Satellite images and pilot observations indicated that an ash plume rose to an altitude of 11.6 km (38,000 ft) a.s.l. The event was also verified by infrasound and lightning data. Another short-lived explosive event began at 1546, detected in infrasound and seismic data. A volcanic cloud identified in satellite images rose as high as 7.6 km (25,000 ft) a.s.l.

An explosion at 0450 on 18 February was detected in seismic, infrasound, and lightning data. The seismic data suggested that ash emissions lasted several minutes, and then seismicity decreased. A preliminary evaluation of satellite data indicated that a cloud rose at least as high as 7.6 km (25,000 ft) a.s.l.; the cloud drifted SW. On 19 February the ACC was lowered to Orange and the VAL was lowered to Watch. Later that day seismic and infrasound data recorded a series of short-lived explosive pulses during 1708-1745. The ACC was raised to Red and the VAL was raised to Warning. A plume identified in satellite images rose as high as 7.6 km (25,000 ft) a.s.l. and drifted 160 km SE over Unalaska Island. AVO geologists on the island described the cloud has having a white upper portion and a slightly darker lower portion. Storms in the region impacted data communications at AVO’s facility in Dutch Harbour on 20 February, limiting AVO’s ability to forecast and detect eruptions at Bogoslof.

Cleveland | Chuginadak Island (USA) : AVO reported that although weather clouds mostly prevented satellite and webcam views of Cleveland during 15-21 February, slightly elevated surface temperatures were identified in satellite imagery during 18-19 February. The Aviation Colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Colima | Mexico : Based on Centro Universitario de Estudios e Investigaciones de Vulcanologia – Universidad de Colima observations, the Unidad Estatal de Protección Civil de Colima reported that during 10-16 February there were 10 low-intensity explosions at Colima. Gas emissions were at low-to-moderate levels. The report noted that the public should not enter the 8-km-radius exclusion zone.

Dukono | Halmahera (Indonesia) : Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 14 and 16-21 February ash plumes from Dukono rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted in multiple directions.

Kilauea | Hawaiian Islands (USA) : During 15-21 February HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kilauea’s Overlook vent. Webcams recorded incandescence from long-active sources within Pu’u ‘O’o Crater and from a vent high on the NE flank of the cone. All surface flows were active within 2.4 km of Pu’u ‘O’o. The 61G lava flow, originating from a vent on Pu’u ‘O’o Crater’s E flank, continued to enter the ocean at Kamokuna.

Langila | New Britain (Papua New Guinea) : Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 17-18 February ash plumes from Langila rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 15 February-21 February 2017

Barren Island | Andaman Islands (India) : The National Institute of Oceanography (NIO), part of the Council of Scientific and Industrial Research (CSIR), reported that a new eruption at Barren Island began on 23 January. Scientists aboard a research vessel were collecting sea floor samples when they observed a sudden ash emission. The team moved closer, about 1.6 km from the volcano, and noted small eruptive episodes lasting 5-10 minutes. Ash emissions were visible in the daytime, and lava fountains feeding lava flows on the flanks were visible at night. The team revisited the volcano on 26 January and observed similar activity during the four hours they stayed. They sampled sediments and water in the vicinity of the eruption and recovered volcanic ejecta.

Krakatau | Indonesia : PVMBG reported that seismicity at Anak Krakatau increased on 17 February, with earthquakes indicating emissions slowing transforming into continuous tremor. Harmonic tremor began to be recorded at 1810 on 19 February. Almost an hour later, at 1904, Strombolian explosions ejected incandescent material 200 m high.

Lanin | Central Chile-Argentina border : Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) reported that beginning at 1524 on 15 February a seismic swarm at Lanin, consisting of 59 volcanic-tectonic, long-period, and spasmodic tremor events, lasted for 45 minutes. The largest volcano-tectonic event was a M 1.8. The Alert Level was raised to Yellow (second highest level on a four-colour scale); ONEMI declared an Alert Level Yellow (the middle level on a three-colour scale) for the community of Curarrehue (32 km N).

Pacaya | Guatemala : INSIVUMEH reported that during 14-21 February small Strombolian explosions at Pacaya’s Mackenney cone periodically generated small lava flows (200 m long on 21 February) that were active for hours at a time. CONRED noted that at night on 15 February residents in Los Positos in Villa Canales (13 km NE), and in Mesillas Altas and Bajas in Amatitlán (12 km N) reported vibrations and rumbling.

Piton de la Fournaise | Reunion Island (France) : OVPF reported that volcanic tremor at Piton de la Fournaise fluctuated during 14-21 February. Lava was mainly transported through a lava tube, and a few branches at end of tube were active.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 8 February-14 February 2017 – cont.

Sabancaya | Peru : Based on webcam views, satellite images, and seismic data the Buenos Aires VAAC reported that during 8-10 and 12-14 February sporadic gas-and-ash puffs rose from Sabancaya as high as an altitude of 9.1 km (30,000 ft) a.s.l.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 3-10 February lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed an ash plume that drifted 112 km NW on 4 February and a thermal anomaly over the dome during 5 and 7-9 February. The Aviation Colour Code remained at Orange.

Sinabung | Indonesia : Based on PVMBG observations, satellite and webcam images, and wind data, the Darwin VAAC reported that during 8-13 February ash plumes from Sinabung rose to altitudes of 3.4-6.7 km (11,000-22,000 ft) a.s.l. and drifted W, SW, and SE.

Suwanosejima | Ryukyu Islands (Japan) : Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 9 February an explosion generated an ash plume from Suwanosejima that rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE.

Turrialba | Costa Rica : OVSICORI-UNA reported that at 1610 on 8 February an ash plume rose 300 m above Turrialba’s active vent and drifted N. An event at 1531 on 10 February also produced an ash plume but inclement weather prevented estimates of the plume height. During 11-12 February variable amplitude tremor was detected, and at night hot blocks ejected from the vent landed in Cráter Central. Several events on 13 February (at 0255, 0305, 0415, and 1459) produced ash plumes that rose as high as 1 km and drifted N, NW, and W. Several small ejections of incandescent material fell around the active crater during the early morning. On 14 February continuous emissions of gas and steam with low ash content were visible. A strong sulphur odor was reported in San Pablo de Oreamuno (25 km SW).

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 8 February-14 February 2017

Bogoslof | Fox Islands (USA) : AVO reported that during 8-12 and 14 February cloud cover prevented satellite views of Bogoslof; no other data indicated eruptive activity. At 0724 on 13 February seismicity significantly increased, prompting AVO to raise the Aviation Colour Code (ACC) to Red and the Volcano Alert Level (VAL) to Warning. Satellite images acquired through 0930 showed no ash emissions above the 3 km (10,000 ft) a.s.l. cloud deck, and no lightning was detected. AVO concluded that, despite the intensity of seismic activity, a significant ash emission was not produced during this event; the ACC was lowered to Orange and the VAL was lowered to Watch.

Colima | Mexico : The Universidad de Colima reported that a large explosion at Colima was recorded at 1732 on 3 February, generating an ash plume that rose 6 km above the crater rim and drifted SSW. A small pyroclastic flow traveled down the E flank. The report stated that the internal crater is about 250 m in diameter and 50-60 m deep; previous lava domes had been destroyed in late September and mid-November 2016. On 9 February the sulphur dioxide gas flux was low (19 tons/day). Based on webcam and satellite images, the Washington VAAC reported that on 11 February an ash plume rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted W. On 14 February an ash plume rose to an altitude of 5.2 km (17,000 ft) a.s.l. and drifted NE.

Dukono | Halmahera (Indonesia) : Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 8-14 February ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted S, SE, and E

Ebeko | Paramushir Island (Russia) : On 10 February KVERT reported that activity at Ebeko had declined, though gas-and-steam emissions continued. The Aviation Colour Code was lowered to Yellow (the second lowest level on a four-colour scale).

Kilauea | Hawaiian Islands (USA) : During 8-14 February HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kilauea’s Overlook vent. Webcams recorded incandescence from long-active sources within Pu’u ‘O’o Crater and from a vent high on the NE flank of the cone. All surface flows were active within 2.4 km of Pu’u ‘O’o. The 61G lava flow, originating from a vent on Pu’u ‘O’o Crater’s E flank, continued to enter the ocean at Kamokuna. A portion of the sea cliff just W of the ocean entry collapsed on 11 February.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 8 February-14 February 2017

Cleveland | Chuginadak Island (USA) : AVO reported that weakly elevated surface temperatures in Cleveland’s summit crater were identified in satellite images during 7-9 February. Minor steaming was noted on 8 February. AVO noted that these observations were consistent with the presence of a lava dome that began extruding in the summit crater in late January. The Aviation Colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Pacaya | Guatemala : On 9 February INSIVUMEH reported that moderate explosions at Pacaya’s Mackenney cone had been detected during the previous few days. Incandescent material was ejected 30-50 m high and filled a large part of the crater; lava spilled over the crater rim and traveled 300 m down the NW flank. Incandescent material was ejected as high as 30 m during 11-12 February. Small Strombolian explosions were visible on 13 February. The lava flow continued to advance the next day.

Piton de la Fournaise | Reunion Island (France) : OVPF reported that during 8-14 February volcanic tremor at Piton de la Fournaise was high, with levels reaching those observed at the onset of the eruption on 31 January. The eruptive vent was perched on top of a cone that was 30-35 m high and 190 m wide (at the base). The lava level inside of the cone was low, or about half of cone’s height, and incandescent material was ejected from the vent. Lava was mainly transported through a lava tube, though a few branches at end of tube were active.

Takawangha | Andreanof Islands (USA) : On 10 February AVO stated that the seismic swarm that began at Takawangha on 23 January had significantly declined the previous week and that seismicity was nearly at background levels. The Aviation Colour Code was lowered to Green and the Volcano Alert Level was lowered to Normal.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 1 February-7 February 2017 – cont.

Kilauea | Hawaiian Islands (USA) : During 1-7 February HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kilauea’s Overlook vent. Webcams recorded incandescence from long-active sources within Pu’u ‘O’o Crater and from a vent high on the NE flank of the cone. The 61G lava flow, originating from a vent on Pu’u ‘O’o Crater’s E flank, continued to enter the ocean at Kamokuna. All surface flows were active within 2.4 km of Pu’u ‘O’o.

HVO geologists noted an extensive crack running parallel to the sea cliff about 5-10 m behind the stream of lava entering the ocean at Kamokuna. The crack was 30 cm wide on 28 January and 70 cm wide four days later, on 1 February. In addition, the seaward block bounded by this crack was visibly moving up to 1 cm, and ground shaking could be felt up to several hundred meters away. On 2 February the crack was wider and steaming, and the stream of lava that had been pouring into the ocean from an opening in a lava tube about 20 m above the water was no longer visible (though lava continued to enter the ocean). At about 1255 almost the entire section of the sea cliff that was seaward of the hot crack collapsed. The collapsed block generated a wave that propagated outward from the coast. After the collapse, no lava was visible entering the ocean though a steam plume and spatter from explosions indicated that the entry remained active.

Sabancaya | Peru : Based on webcam and satellite views, the Buenos Aires VAAC reported that sporadic gas-and-ash puffs rose from Sabancaya during 2-6 February. Weather clouds sometimes prevented visual observations.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 27 January-3 February lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed a daily thermal anomaly over the dome. The Aviation Color Code remained at Orange.

Sinabung | Indonesia : Based on PVMBG observations, satellite and webcam images, and wind data, the Darwin VAAC reported that during 2-7 February ash plumes from Sinabung rose to altitudes as high as 7.3 km (24,000 ft) a.s.l. and drifted NE, E, SE, and SW.

BNPB reported that each day during 2-7 February there were 8-12 ash-producing events with plumes rising as high as 2 km above the crater and drifting E. Pyroclastic flows traveled as far as 2 km S, SE, and E. BNPB noted that more areas had been designated disaster prone, therefore the number of people needed to be relocated also increased. The Alert Level remained at 4 (on a scale of 1-4), with an exclusion zone of 7 km from the volcano on the SSE sector, and 6 km in the ESE sector, and 4 km in the NNE sector.

Turrialba | Costa Rica : On 1 February OVSICORI-UNA reported that since 27 January the seismic network at Turrialba recorded variable-amplitude, discontinuous tremor indicative of moving pressurized volcanic fluid. Passive emissions of ash were observed during 1-2 February, rising as high as 500 m above the crater. Ashfall was reported in Desamparados, Calle Blancos, and Tres Ríos, and a sulphur odour was noted in San Pablo Heredia. An eruption at 0900 on 4 February generated an ash plume that rose 300 m and drifted W. Almost continuous ash emissions rose at most 500 above the crater during 4-5 February and drifted WSW. Variable-amplitude tremor continued to be recorded.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 1 February-7 February 2017

Bogoslof | Fox Islands (USA) : AVO reported that no further emissions were detected at Bogoslof after an explosion at 0520 on 31 January; the Aviation Color Code (ACC) was lowered to Orange and the Volcano Alert Level (VAL) was lowered to Watch the next day. A burst of tremor lasting nine minutes was detected starting at 0457 on 3 February. A second burst, starting at 0533 and lasting 20 minutes, was also detected by infrasound instruments, indicating an explosion. No ash cloud was detected above the meteorological cloud deck in satellite data. An event that began at 1642 produced a small volcanic plume that drifted about 40 km N below an altitude of 7.6 km (25,000 ft) a.s.l. Seismic tremor significantly decreased later that evening. Weakly elevated surface temperatures were observed in two satellite images acquired on 5 February, possibly related to hot deposits from explosive activity the day before.

Colima | Mexico : The Washington VAAC reported that on 1 February an ash emission was recorded by the webcam rising from Colima. Weather clouds prevented satellite observations of the event. Based on webcam and satellite images, the Mexico City MWO, and model data, the VAAC noted that during 3-6 February ash plumes rose to altitudes of 5.2-7.6 km (17,000-25,000 ft) a.s.l. and drifted NW, W, SW, and S.

Dukono | Halmahera (Indonesia) : Based on analyses of satellite imagery and model data, the Darwin VAAC reported that during 1-2 and 5-7 February ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted at least 130 km SE and E.

Ebeko | Paramushir Island (Russia) : KVERT reported that moderate gas-and-steam emissions possibly containing small amounts of ash continued at Ebeko during 27 January-3 February. Minor ashfall was reported in Severo-Kurilsk (Paramushir Island) about 7 km E on 30 January. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Fuego | Guatemala : In a special report from 2 February, INSIVUMEH noted increased activity at Fuego characterized by explosions occurring every 5-15 minutes. Ash plumes rose as high as 750 m and drifted 15 km W, causing ashfall in areas downwind including Sangre de Cristo and San Pedro Yepocapa. During 2-7 February explosions generated ash plumes that rose 0.4-1.1 km above the crater and drifted at most 12 km NW, W, SW, and S. Incandescent material was ejected 150 m high, and avalanches traveled down the Taniluyá (SW) and Ceniza (SSW) drainages. Ashfall was reported in areas downwind including Sangre de Cristo (8 km WSW), Santa Sofía (12 km SW), El Porvenir (8 km ENE), Rochela, and Panimaché I and II (8 km SW). Shock waves from explosions rattled nearby structures.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 1 February-7 February 2017

Chirinkotan | Kuril Islands (Russia) : On 6 February SVERT noted that the Aviation Colour Code for Chirinkotan had been lowered to Green (lowest level on a four-colour scale).

Cleveland | Chuginadak Island (USA) : On 3 February AVO reported that recent satellite data indicated that a new lava dome had been extruded, and partially filled Cleveland’s summit crater. The new dome is about 70 m in diameter, similar in size to previous lava domes that have developed on the crater floor. Since explosive activity has sometimes followed lava-dome extrusion, AVO increased the Aviation Color Code to Orange and the Volcano Alert Level to Watch. Weakly elevated surface temperatures were identified in several satellite images during 6-7 February, consistent with the presence of a lava dome that began forming in late January.

Takawangha | Andreanof Islands (USA) : On 3 February AVO stated that the seismic swarm that began at Takawangha on 23 January continued but at a decreased rate and intensity. The rate of earthquakes peaked at 190 events on 24 January, and since then had steadily declined; 2-8 events per day were recorded from late January to 3 February. Most of the events were located 7-8 km ESE, at shallow depths. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Piton de la Fournaise | Reunion Island (France) : OVPF reported that seismicity and inflation at Piton de la Fournaise significantly increased on 2 January. Based on seismic data, an eruption began at 1940 on 31 January. Visual observations on 1 February confirmed that the active vent was located about 1 km SE of Château Fort and about 2.5 km ENE of Piton de Bert. Lava fountains rose 20-50 m above the 10-m-high vent, and ‘a’a lava flows branched and traveled 750 m. Two other cracks had opened at the beginning of the eruption but were no longer active. Tremor levels decreased in the early hours of the eruption; RSAM values then fluctuated at mid-range, and lava-fountain heights were variable (between 20-50 m). On 2 February two lava fountains at the vent were visible, and lava flows had traveled an additional 500 m E. The vent was 128 m long and about 35 m high at the highest part. The next day RSAM levels were more stable, at a value which was half of what it was at the beginning of the eruption. On 4 February OVPF noted that significant fluctuations of volcanic tremor were detected for more than 24 hours, with intensity levels reaching those observed at the onset of the eruption. Higher levels of seismicity continued through 7 February. Poor weather conditions prevented visual observations during 4-7 February.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 25 January-31 January 2017 – Cont.

Nevado del Ruiz | Colombia : Based on analysis of satellite images, the Washington VAAC reported that on 31 January an ash plume from Nevado del Ruiz rose to an altitude of 7 km (23,000 ft) a.s.l. and drifted W.

Popocatepetl | Mexico : Each day during 25-31 January CENAPRED reported 2-55 steam and gas emissions from Popocatépetl and crater incandescence at night. The Alert Level remained at Yellow, Phase Two.

Sabancaya | Peru : Based on webcam and satellite views, and seismic data, the Buenos Aires VAAC reported that sporadic gas-and-ash puffs rose from Sabancaya during 25-31 January. Weather clouds sometimes prevented visual observations. A field team from IGP’s Observatorio Vulcanológico del Sur (OVS) visited Sabancaya on 26 January and observed ash plumes from explosions rising about 2 km above the crater rim.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 20-27 January lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed a daily thermal anomaly over the dome. The Aviation Colour Code remained at Orange.

Sinabung | Indonesia : Based on PVMBG observations, Indonesian Met Office observations, satellite images, and wind data, the Darwin VAAC reported that during 27-30 January ash plumes from Sinabung rose 3.3-4.6 km (11,000-15,000 ft) a.s.l. and drifted SW and SSE.

Suwanosejima | Ryukyu Islands (Japan) : Based on JMA notices and satellite-image analyses, the Tokyo VAAC reported that on 26 January an ash plume from Suwanosejima rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted SE.

Turrialba | Costa Rica : Based on webcam views, the Washington VAAC reported ongoing ash emissions at Turrialba on 27 January.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 25 January-31 January 2017

Bagana | Bougainville (Papua New Guinea) : Based on analyses of satellite imagery, the Darwin VAAC reported that on 25 January an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SE.

Bogoslof | Fox Islands (USA) : AVO reported that no further emissions were detected at Bogoslof after an explosion at 0453 on 24 January; the Aviation Color Code (ACC) was lowered to Orange and the Volcano Alert Level (VAL) was lowered to Watch the next day. An hour-long seismic increase began at 0134 on 25 January though no evidence of eruptive activity was evident. Based on lightning and seismic data an explosive event began at 0650 on 26 January, and another burst of seismicity was recorded at 0706. The ACC was raised to Red and the VAL was raised to Warning. An ice-rich cloud, first identified in satellite data at 0700, likely contained ash, and rose as high as 9.8 km (32,000 ft) a.s.l. and drifted SE at lower altitudes, and NE at altitudes above about 6.1 km (20,000 ft) a.s.l. The ACC was lowered to Orange and the VAL was lowered to Watch later that day. Lightning and seismic data again indicated an explosive event at 0824 on 27 January, prompting AVO to raise the Aviation Colour Code (ACC) to Red and the Volcano Alert Level (VAL) to Warning. An ice-rich cloud that likely contained ash rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted E; seismicity related to ash emissions remained elevated for 48 minutes. The ACC was lowered to Orange and the VAL was lowered to Watch later that day.

Several short bursts of seismic activity were detected at 0520 and 0608 on 30 January. An infrasound signal accompanied the first event indicating an explosion; an eruption cloud was identified in satellite data at 0530, rising to an altitude of 6.1 km (20,000 ft) a.s.l. later that day AVO noted that bursts of explosive activity continued and intensified; more than 10 short-duration explosions were detected in seismic, infrasound, and lightning data. The Aviation Colour Code (ACC) was raised to Red and the Volcano Alert Level (VAL) was raised to Warning. Ash plumes rose as high as 7.6 km (25,000 ft) a.s.l. and drifted 125 km SE. Trace amounts of ashfall and a sulphur odour were reported in Unalaska/Dutch Harbour (98 km E). By the next day the explosions had subsided or ended. Satellite images acquired on 31 January showed significant changes to the island. AVO stated that freshly erupted volcanic rock and ash had formed a barrier that separated the vent from the sea, suggesting that the change had resulted in the more ash-rich emissions occurring during 30-31 January.

Colima | Mexico : Based on webcam and satellite images, the Mexico City MWO, and model data, the Washington VAAC reported that during 25-29 January ash plumes from Colima rose to altitudes of 4.7-7 km (17,000-26,000 ft) a.s.l. and drifted NE. Ash plumes were identified in satellite images at least 370 and 650 km NE of Colima on 25 and 27 January, respectively.

Dukono | Halmahera (Indonesia) : Based on analyses of satellite imagery, model data, and notices from PVMBG, the Darwin VAAC reported that during 25-26 and 29-31 January ash plumes from Dukono rose to altitudes of 1.5-2.4 km (5,000-8,000 ft) a.s.l. and drifted NE, E, ESE, and SW.

Ebeko | Paramushir Island (Russia) : KVERT reported that moderate gas-and-steam emissions possibly containing small amounts of ash may have continued at Ebeko during 20-27 January. The Aviation Colour Code remained at Orange (the second highest level on a four-colour scale).

Fuego | Guatemala : Based on INSIVUMEH notices, CONRED reported that at 1345 on 25 January a Strombolian phase began at Fuego. Weak-to-moderate explosions generated ash plumes that rose 750 m above the crater rim and drifted 10 km W and SW. Lava fountains rose 200 m above the crater rim and fed lava flows that traveled 1 km SSW down the Ceniza drainage. Avalanches of material advanced more than 300 m down the Ceniza and Trinidad (S) drainages into vegetated areas. Ash fell on the SW and W flanks. The report also noted that a previous Strombolian phase had begun on 3 January.

INSIVUMEH reported that during 27-31 January explosions generated ash plumes that rose 500-900 m and drifted 5-10 km W, SW, S, and SE. Avalanches of material descended the Ceniza, Trinidad, and Santa Teresa (W) drainages.

Kilauea | Hawaiian Islands (USA) : During 25-31 January HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kilauea’s Overlook vent. Webcams recorded incandescence from long-active sources within Pu’u ‘O’o Crater and from a vent high on the NE flank of the cone. The 61G lava flow, originating from a vent on Pu’u ‘O’o Crater’s E flank, continued to enter the ocean at Kamokuna. All surface flows were active within 2.4 km of Pu’u ‘O’o.

HVO noted that thermal images showed a high-temperature area about 5-10 m from the edge of the sea cliff, with hot cracks running parallel to the cliff around the entry point, suggesting sea cliff instability. HVO scientists did not observe significant delta development from ground vantage points on 29 January. A stream of lava continued to pour into the ocean from an opening in a lava tube about 20 m above the water.

Langila | New Britain (Papua New Guinea) : Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 25-27 January ash plumes from Langila rose to altitudes of 1.8-3 km (6,000-10,000 ft) a.s.l. and drifted NW and N.

Volcanos

Roundup of Global Volcanic Activity – New Activity for the week of 25 January-31 January 2017

Chirinkotan | Kuril Islands (Russia) : Based on satellite images, SVERT reported that on 26 and 29 January ash plumes from Chirinkotan rose to an altitude of 3.5 km (11,500 ft) a.s.l. and drifted at most 105 km E and S. The Aviation Colour Code remained at Yellow (on a four-colour scale).

Erta Ale | Ethiopia : According to Volcano Discovery, visitors noted changes at Erta Ale’s lava lake during 16-20 January characterized by waves in the lava lake, intense spattering, fountaining, and rim overflows (mainly on 17 January) which traveled as far as 1 km. During the evening of 20 January explosions of very large gas bubbles ejected spatter 30 m high. Crater rim collapses affected the N crater where a new oval-shaped pit crater (150 x 30 m and 20 m depth) formed during a 24-hour period. A large collapse also occurred in the S part of the crater. The activity was accompanied by ash emissions that rose as high as 800 m. The report noted that on 21 January new fissures opened SSE from the summit caldera, producing large amounts of lava.

Satellite images acquired and processed by Planet Labs showed the new lava flows and gas-and-steam emissions from several vents (about 1.5 km SE from the overflow area at the SE caldera rim) on 23 January, and more new lava flows on 27 January. Both images showed lava flows advancing WSW, about 2.5 km S, and about 3 km NE. According to NASA’s Earth Observatory, a satellite image acquired on 26 January showed two distinct infrared hotspots representing the SE lava flows. On 27 January Simon Carn stated that the eruption produced the largest SO2 emissions from Erta Ale ever measured from space.

Etna | Sicily (Italy) : INGV reported that on the morning of 15 December 2016 minor emissions of brownish ash rose from the vent in the saddle between the newer cone and the old cone of Etna’s Southeast Crater (SEC). That evening some of the emissions were more energetic, ejecting incandescent material out of the crater which landed on the steep S flank of the SEC cone. Analysis of samples of the ejected rock revealed no new material, only older material from the conduit walls. During the following five weeks weak ash emissions from the vent were observed, without being accompanied by incandescence.

During the early morning of 20 January the saddle vent was again active, with small black ash puffs and thermal anomalies identified by the surveillance camera. People on the SEC observed ejected incandescent material along with ash and blocks. Cloudy weather prevented visual observations for a few days; the evening of 23 January was cloud free and mild Strombolian activity was observed, accompanied by frequent emissions of small, black ash puffs. The activity gradually intensified through the night, with some explosions launching incandescent material as far as the base of the SEC cone. Fluctuating incandescence was also visible at the 7 August 2016 vent of the Voragine (VOR) crater. The frequency of explosions and ash emissions increased on 24 January but then slightly decreased the next morning.

Takawangha | Andreanof Islands (USA) : On 27 January AVO stated that the seismic swarm that began at Takawangha on 23 January had significantly decreased during the previous day. The rate of earthquakes peaked at 190 events on 24 January and had steadily decreased to 22 detected on 27 January. Most of the events were located 7-8 km ESE, at shallow depths. The swarm continued at a decreased rate and intensity through 31 January. The Aviation Colour Code remained at Yellow and the Volcano Alert Level remained at Advisory.

Unnamed | Tonga Islands : Based on analysis of satellite images, GeoNet reported that a submarine eruption at an Unnamed volcano (GVP volcano number 243030) about 46 km NW of Tonga’s capital Nuku’alofa began on 23 January. Activity was also identified in images from 26, 28, 29, and 31 January, characterized by discoloured water, and a volcanic plume on 31 January.

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Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 18 January-24 January 2017 – Cont.

Pacaya | Guatemala : INSIVUMEH reported that at night during 21-22 January incandescence was reflected from emissions above Pacaya’s Mackenney cone. In a 24 January report, INSIVUMEH noted that gas-and-ash emissions had continued, with deposits filling in the crater on top of the cone. Nighttime incandescence continued to be observed.

Sabancaya | Peru : Based on webcam and satellite views, the Buenos Aires VAAC reported that sporadic gas-and-ash puffs rose from Sabancaya during 17-24 January. Meteorological cloud cover sometimes prevented observations.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 13-20 January lava-dome extrusion onto Sheveluch’s N flank was accompanied by strong fumarolic activity, dome incandescence, ash explosions, and hot avalanches. Satellite images showed a daily thermal anomaly over the dome. The Aviation Colour Code remained at Orange.

Sinabung | Indonesia : Based on PVMBG observations, satellite images, and wind data, the Darwin VAAC reported that during 19-20, 22, and 24 January ash plumes from Sinabung rose 3.9-4.9 km (13,000-16,000 ft) a.s.l. and drifted NW, SW, and SE.

Turrialba | Costa Rica : Based on webcam and satellite views, the Washington VAAC reported that on 22 January an ash plume from Turrialba rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted E.

Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 18 January-24 January 2017

Bagana | Bougainville (Papua New Guinea) : Based on analyses of satellite imagery, the Darwin VAAC reported that on 19 January an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SE. On 24 January ash plumes visible in satellite images and observed by a pilot rose to altitudes of 3-4.3 km (10,000-14,000 ft) a.s.l and drifted almost 140 km NE.

Colima | Mexico : The Unidad Estatal de Protección Civil de Colima reported that at 0027 on 18 January a moderate-to-large explosion at Colima ejected incandescent material as far as 2 km onto the W, SW, SE, and N flanks. Based on webcam and satellite images, the Mexico City MWO, and pilot observations, the Washington VAAC reported that during 18-24 January ash plumes from Colima rose to altitudes of 4.1-6.7 km (15,000-25,000 ft) a.s.l. and drifted in multiple directions. On 19 January explosions were recorded by the webcam and noted by the Jalisco Civil protection agency; ashfall was also reported in Comala and Cuauhtémoc by the agency. A strong thermal anomaly was identified in satellite images. Remnant ash clouds were centered about 350 km SE on 20 January and about 185 km S on 22 January. A large ash plume rose to an altitude of 10.7 km (35,000 ft) a.s.l. on 23 January and drifted NE.

Dukono | Halmahera (Indonesia) : Based on analyses of satellite imagery, model data, and notices from PVMBG, the Darwin VAAC reported that during 18-24 January ash plumes from Dukono rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted S, SW, W, and NW.

Kilauea | Hawaiian Islands (USA) : During 18-24 January HVO reported that the lava lake continued to rise and fall, circulate, and spatter in Kilauea’s Overlook vent. Webcams recorded incandescence from long-active sources within Pu’u ‘O’o Crater and from a vent high on the NE flank of the cone. The 61G lava flow, originating from a vent on Pu’u ‘O’o Crater’s E flank, continued to enter the ocean at Kamokuna. All surface flows were active within 2.4 km of Pu’u ‘O’o.

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that during 13-20 January gas-and-steam emissions from Klyuchevskoy sometimes contained minor amounts of ash. Satellite images showed a daily thermal anomaly over the volcano. On 22 January an ash plume rose to altitudes of 5-5.5 km (16,400-18,000 ft) a.s.l. and drifted 45 km E. The Aviation Colour Code was raised to Orange (the second highest level on a four-colour scale), but was again lowered to Yellow on 24 January.

Masaya | Nicaragua : Based on satellite images, the Washington VAAC reported that on 21 January a possible emission from Masaya with minor ash content drifted almost 25 km NW.