Volcanos

Global Volcanic Activity – Ongoing Activity for the week of 9 October – 15 October 2019

Aira | Kyushu (Japan) : JMA reported that incandescence from Minamidake crater (at Aira Caldera’s Sakurajima volcano) was occasionally visible at night during 7-15 October. There were 13 explosions detected by the seismic network and nine non-explosive eruptive events. Eruption plumes rose 2.3-2.7 km above the crater rim and large blocks were ejected as far as 1.7 km away. The sulfur dioxide emission rate was high, at 2,100 tons/day, on 11 October. The Alert Level remained at 3 (on a 5-level scale).

Ambrym | Vanuatu : Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that data and observations during February-October indicated that conditions at Ambrym had become stable after the eruption in December 2018 that focused on the summit caldera and East Rift Zone. On 10 October the Alert Level was lowered to 1 (on a scale of 0-5) indicating minor unrest. VMGD warned the public to stay outside of the Permanent Danger Zone defined as a 1-km radius from Benbow Crater and a 2-km radius from Marum Crater, and additionally to stay away from the ground cracks resulting from the December 2019 eruption (a 500-m-radius around the major cracks at Paamal village).

Asosan | Kyushu (Japan) : JMA reported that during 7-15 October ash plumes rose as high as 1.3 km above Asosan’s summit crater rim, causing ashfall in areas downwind including periodically at the Kumamoto Regional Meteorological Observatory. Crater incandescence was occasionally visible at night. The sulfur dioxide emission rate was very high at 4,000 tons per day on 11 October. The Alert Level remained at 2 (on a scale of 1-5).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 9-15 October ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : KVERT reported that ash from Ebeko was reported in Severo-Kurilsk (Paramushir Island), about 7 km E, during 4-5 October. Volcanologists in Severo-Kurilsk observed explosions during 7-8 and 10 October that sent ash plumes up to 2.5 km (8,200 ft) a.s.l. and drifted E and NE. A weak thermal anomaly was identified in satellite images on 8 October. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Ibu | Halmahera (Indonesia) : PVMBG reported that at 0707 on 15 October an ash plume from Ibu rose at least 400 m above the summit and drifted S. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 7-15 October lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.5 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose to 400 m above the summit. The Alert Level remained at 2 (on a scale of 1-4).

Krakatau | Indonesia : PVMBG reported that at 1010 and 1226 on 12 October, 1026 on 13 October, and 1228 on 14 October the webcam at Anak Krakatau recorded dense gray-black ash plumes rising about 200 m above the bottom of the crater and drifting N. The 14 October event was recorded by the seismic network for three minutes. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

Reventador | Ecuador : IG reported that during 8-15 October seismic data from Reventador’s network indicated a high level of seismic activity, including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions. Weather often prevented views of the summit area, although during clear conditions ash-and-steam plumes were visible rising sometimes higher than 1 km above the crater rim and drifting NW, W, and SW. Crater incandescence was periodically observed at night. Blocks were observed rolling down the flanks on 10 and 14 October.

Sabancaya | Peru : Instituto Geofísico del Perú (IGP) reported that an average of 36 low-to-medium intensity explosions per day occurred at Sabancaya during 7-13 October. Gas-and-ash plumes rose as high as 3.5 km above the summit and drifted SE and SW. There were 15 thermal anomalies identified in satellite data. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 12-km radius.

Semeru | Eastern Java (Indonesia) : The Darwin VAAC reported that during 13-14 September ash plumes from Semeru rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted SW based on satellite images and weather models. The Alert Level remained at 2 (on a scale of 1-4).

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 4-11 October. Explosions seen in video and satellite images on 6 and 9 October produced ash plumes that rose 6.5-11 km (21,300-36,100 ft) a.s.l. and drifted 1,100 km E. Resuspended ash drifted 170 km E on 4 and 8 October. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

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Volcanos

Global Volcanic Activity – New Activity for the week of 9 October – 15 October 2019

Metis Shoal | Tonga Islands : According to news articles the Tonga Geological Services Office of the Ministry of Lands and Natural Resources stated that several observations indicating a possible eruption at Metis Shoal, also known as Lateiki, were reported during 13-15 October. Real Tonga pilots flying between Tongatapu and Vava’u observed the intermittent plumes rising to 4.6-5.2 km (15,000-17,000 ft) a.s.l. and drifting N on 15 October. Ash in the plumes was not identifiable according to the Wellington VAAC.

Volcanos

Global Volcanic Activity – Ongoing Activity for the week of 2 October – 8 October 2019

Aira | Kyushu (Japan) : JMA reported that incandescence from Minamidake crater (at Aira Caldera’s Sakurajima volcano) was occasionally visible at night during 30 September-7 October. The sulfur dioxide emission rate was high, at 2,000 tons/day, measured during fieldwork on 1 October. An explosion was recorded at 0055 on 4 October but weather clouds prevented visual confirmation. Two explosions during 6-7 October generated ash plumes that rose as high as 2.4 km above the crater rim and ejected large blocks 1.1 km away. The Alert Level remained at 3 (on a 5-level scale).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 2-8 October ash plumes from Dukono rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 27 September-4 October that sent ash plumes up to 4 km (13,100 ft) a.s.l. Ash plumes drifted SE, E, and NE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Fuego | Guatemala : INSIVUMEH reported that there were 10-18 explosions per hour recorded at Fuego during 2-8 October, generating ash plumes that rose as high as 1.1 km above the crater rim and drifted 10-25 km S, SW, W, and NW. Ashfall was reported in several areas downwind including Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché I and II (8 km SW), Finca Palo Verde, San Pedro Yepocapa (8 km NW), and El Porvenir (8 km ENE). Explosions sometimes produced shock waves that rattled houses in nearby communities. Incandescent material was ejected 200-400 m high and caused avalanches of material that occasionally traveled long distances (reaching vegetated areas) down the Seca (W), Taniluyá (SW), Ceniza (SSW), Trinidad (S), El Jute (SE), Las Lajas (SE), and Honda ravines. Lava flows traveled 200 m down the Seca drainage on 6 October and were active in the Santa Teresa (W) drainage on 8 October. Lahars descended the Ceniza, El Mineral, and Seca drainages during 3-7 October, carrying tree branches, trunks, and blocks 1-3 m in diameter.

Hakoneyama | Honshu (Japan) : On 7 October JMA lowered the Alert Level for Hakoneyama to 1 (the lowest level on a 5-level scale), noting that the number of volcanic earthquakes had decreased to background levels after a spike in seismicity was recorded in May. Inflation had been detected but had become almost stagnant after late August. Fumaroles in the Owakudani hot springs area continued to be active, with gas-and-steam plumes rising 100-400 m above their vents.

Ibu | Halmahera (Indonesia) : The Darwin VAAC reported that during 6-7 October ash plumes from Ibu rose to altitudes of 2.1-2.7 km (7,000-9,000 ft) a.s.l. and drifted S and N based on satellite images and weather models. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 30 September-6 October lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.8 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose to 300 m above the summit. The Alert Level remained at 2 (on a scale of 1-4).

Karymsky | Eastern Kamchatka (Russia) : On 3 October KVERT reported that a weak thermal anomaly over Karymsky continued to be periodically visible in satellite images. Ash explosions were last recorded on 24 September. The Aviation colour Code was lowered to Yellow (the second lowest level on a four-colour scale).

Kerinci | Indonesia : PVMBG reported that at 1253 on 6 October a brown ash emission from Kerinci rose around 600 m above the summit and drifted WSW according to a ground observer. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 3-km exclusion zone.

Krakatau | Indonesia : PVMBG reported that Anak Krakatau’s seismic network recorded one eruptive event during 30 September-6 October. A webcam at the summit recorded diffuse white plumes rising as high as 50 m above the crater rim. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

Manam | Papua New Guinea : RVO reported that white emissions rose from Manam during 1-7 October and variable crater incandescence from Main Crater was visible at night. Seismicity was at low to moderate levels with RSAM values fluctuating around 300 units. The Darwin VAAC reported that during 3-4 October diffuse ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted N and NW, based on satellite data and weather models. A thermal anomaly was also visible.

Nevado del Ruiz | Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 24 September-1 October seismicity at Nevado del Ruiz increased in both frequency and magnitude compared to the previous week. Steam-and-gas plumes rose as high as 1.4 km above the summit and drifted mainly NW. A tremor pulse recorded at 2353 on 29 September was associated with an ash plume that drifted NW and was observed by Parque Nacional Natural los Nevados (PNNN) officials, SGC staff in the field, and residents of Manizales (25 km NW). Seismicity continued to indicate gas-and-ash emissions during 1-4 October. Beginning at 0138 on 4 October seismicity increased; several ash emissions were visible during the morning in webcam images and by SGC staff in the field. The emissions rose as high has 800 m and drifted mainly NW, causing ashfall locally and in Manizales. The Alert Level remained at 3 (Yellow; the second lowest level on a four-colour scale).

Nevados de Chillan | Chile : ONEMI and SERNAGEOMIN reported that during 2-8 October white-to-gray gas plumes from Nevados de Chillán’s Nicanor Crater rose as high as 1 km above the rim and drifted ESE, S, and SE. Explosions on 2 and 6 October ejected incandescent material onto the flank. The lava flow on the NNE flank ceased advancing around 6 October, and small pyroclastic flows were recorded during 6-8 October. The volcano Alert Level remained at Orange, the second highest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.

Santa Maria | Guatemala : INSIVUMEH reported that each day during 2-8 October there were as many as five explosions per hour detected at Santa María’s Santiaguito lava-dome complex. Ash plumes rose 700-900 m above the complex and drifted SW. Avalanches of material descended the SE and S flanks. Ash fell in Monte Claro (S) on 2 October.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that during 29 September and 1-2 October video and satellite images recorded ash plumes from explosions at Sheveluch rising as high as 9 km (29,500 ft) a.s.l., and a notable pyroclastic flow traveled SE on 1 October. Ash plumes from the events drifted 1,400 km SE and E. On 6 October satellite images showed ash plumes rising to 10 km (32,800 ft) a.s.l. and drifting 430 km NE. The Aviation colour Code was raised to Red (the highest level on a four-colour scale). Later that day the ash plumes were visible in satellite images drifting 1,080 km ENE. The Alert Level was lowered back to Orange.

Tangkubanparahu | Western Java (Indonesia) : PVMBG reported that during 30 September-6 October diffuse white water vapor plumes rose 150 m above the vent on Tangkubanparahu’s Ratu Crater floor. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.

Volcanos

Global Volcanic Activity – New Activity for the week of 2 October – 8 October 2019

Copahue | Central Chile-Argentina border : OVDAS-SERNAGEOMIN and ONEMI reported that during 2-7 October a webcam at Copahue recorded white and gray emissions rising as high as 300 m above the El Agrio Crater rim and drifting ENE, SE, and SSE. By 7 October the number and intensity of seismic events detected at Copahue had decreased to low levels. The volcano Alert Level was lowered to Yellow (second lowest level on a four-colour scale). ONEMI maintained the Yellow Alert (the middle level on a three-colour scale) for residents, and stated that the public should stay at least 1 km away from El Agrio Crater.

Ulawun | New Britain (Papua New Guinea) : RVO reported that the fissure eruption on Ulawun’s WSW flank had ceased by 4 October, producing only diffuse white-to-gray steam plumes with a blueish tinge from the main coalesced vent. Weak incandescence from the vent was visible at night on 5 October. The lava-flow rate slowed to 3-5 m a day, likely because it was no longer being fed. RSAM decreased to 1,000 units; regular small high-frequency events were recorded during 4-7 October. RVO recommended that the Alert Level be reduced to Stage 2.

Volcanos

Global Volcanic Activity – Ongoing Activity for the week of 25 September – 1 October 2019

Aira | Kyushu (Japan) : JMA reported that incandescence from Minamidake crater (at Aira Caldera’s Sakurajima volcano) was occasionally visible at night during 24-30 September. Very small eruptive events were recorded. The Alert Level remained at 3 (on a 5-level scale).

Asosan | Kyushu (Japan) : JMA reported that during 25-30 September ash plumes rose as high as 1.6 km above Asosan’s summit crater rim and drifted NE and NW, causing ashfall in areas downwind. The sulfur dioxide emission rate was 2,600 tons per day on 26 September. The Alert Level remained at 2 (on a scale of 1-5).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 25 September-1 October ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 22-23 September that sent ash plumes up to 3 km (10,000 ft) a.s.l. Ash plumes drifted E and NE, causing ashfall in Severo-Kurilsk. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that intense Strombolian activity from vents at the bottom of Etna’s Voragine Crater (VOR) continued during 23-29 September. Gas emissions from Northeast Crater (NEC) were intense and continuous, and ash plumes were occasionally visible and sometimes accompanied by incandescent flashes. A large ash emission rose from the crater on 27 September and drifted S.

Ibu | Halmahera (Indonesia) : The Darwin VAAC reported that on 28 September ash plumes from Ibu rose to altitudes of 1.8-2.1 km (6,00-7,000 ft) a.s.l. and drifted WNW based on satellite images and weather models. PVMBG reported that at 1806 on 30 September an ash plume rose about 800 m above the crater rim and drifted N. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 25 September-1 October lava continued to effuse from Karangetang’s Main Crater (S), traveling as far as 1.5 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose to 300 m above the summit. On 27 and 29 September the Darwin VAAC noted that ash plumes rose to 2.1-2.4 km (7,000-8,000 ft) a.s.l. (about 330-640 m above the crater rim) and drifted SW and W. The Alert Level remained at 2 (on a scale of 1-4).

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images on 19 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Krakatau | Indonesia : PVMBG reported that Anak Krakatau’s seismic network recorded 10 eruptive events during 23-29 September. A webcam at the summit recorded diffuse white plumes rising as high as 150 m from the vent at the bottom of the crater. Eruptive events recorded by the webcam at 0813 on 25 September, 0555 and 0835 on 26 September, and 1520 on 27 September generated dense gray-and-white ash plumes that rose 150-200 m from the vent and generally drifted N. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

Manam | Papua New Guinea : The Darwin VAAC reported that on 29 September diffuse ash plumes from Manam rose to altitudes of 2.4-2.7 km (8,000-9,000 ft) a.s.l. and drifted W, based on satellite data and weather models. A sulfur dioxide signature in the plume was also detected. On 30 September RVO reported increased seismicity; the VAAC noted ongoing emissions and a persistent thermal anomaly.

Merapi | Central Java (Indonesia) : PVMBG reported that the lava dome at Merapi slowly grew during 20-26 September and was an estimated 468,000 cubic meters, based on 19 September measurements based on drone photos. Extruded lava fell into the upper parts of the SE flank, generating three block-and-ash flows that traveled as far as 1.5 km down the Gendol drainage. Diffuse white plumes rose as high as 75 m above the summit. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.

Nevados de Chillan | Chile : ONEMI and SERNAGEOMIN reported that during 24 September-1 October white-to-gray gas plumes from Nevados de Chillán’s Nicanor Crater rose as high as 1.3 km above the rim and drifted NE, E, and SE. Explosions sometimes ejected incandescent material onto the flanks. A lava flow on the NNE flank continued to advance at a low rate. Ashfall was reported 15 km WNW in Las Trancas on 24 September. The Alert Level remained at Orange, the second highest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.

Popocatepetl | Mexico : CENAPRED reported that each day during 25 September-1 October there were 123-224 steam-and-gas emissions from Popocatépetl, some of which contained ash. As many as 10 explosions were recorded each day and crater incandescence was sometimes visible at night. During an overflight on 27 September observatory staff, scientists, and civil protection staff observed a lava dome, 30 m in diameter, at the bottom of the inner crater. The inner crater was 350 m in diameter and 150 m deep based on thermal images and photographs. The Alert Level remained at Yellow, Phase Two (middle level on a three-colour scale).

Sabancaya | Peru : Instituto Geofísico del Perú (IGP) reported that an average of 15 low-to-medium intensity explosions per day occurred at Sabancaya during 23-29 September. Gas-and-ash plumes rose as high as 1.7 km above the summit and drifted NW, W, and SW. There were 11 thermal anomalies identified in satellite data. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 12-km radius.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 20-27 September. Explosions recorded during 20-21, 23, and 26 September produced ash plumes that rose to 7 km (23,000 ft) a.s.l. and drifted 580 km ESE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Shishaldin | Fox Islands (USA) : On 26 September AVO reported that seismicity at Shishaldin had decreased during the previous few weeks to levels slightly above background. Satellite images indicated decreased surface temperatures at the summit over the same period and showed collapse and slumping of the floor of the summit crater, suggesting a withdrawal of magma. Tiltmeter data suggested that the collapse may have occurred on 19 September. The Aviation colour Code was lowered to Yellow and the Volcano Alert Level was lowered to Advisory.

Suwanosejima | Ryukyu Islands (Japan) : JMA reported that during 20-27 September white plumes rose 800 m above the rim of Suwanosejima’s Ontake Crater and crater incandescence was visible at night. The Alert Level remained at 2 (on a 5-level scale).

Tangkubanparahu | Western Java (Indonesia) : PVMBG reported that during 23-29 September diffuse white water vapor plumes rose 200 m above the vent on Tangkubanparahu’s Ratu Crater floor. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.

White Island | North Island (New Zealand) : GeoNet reported observing small-scale geyser-like explosions of mud and steam at White Island’s active vent area during the previous three weeks. The ejecta rose as high as 10 m above the active vents on the W part of the crater floor. An increase in frequency of these events was caused by crater lake water that has been rising since early August, covering the active vents. The geysering does not represent increased volcanic activity; the Volcanic Alert Level remained at 1 (the second lowest level on a 0-5 scale) and the Aviation colour Code remained at Green.

Volcanos

Global Volcanic Activity – New Activity for the week of 25 September – 1 October 2019

Copahue | Central Chile-Argentina border : On 30 September OVDAS-SERNAGEOMIN, ONEMI, and SEGEMAR reported that three long-period (LP) earthquakes with notable magnitudes were located about 5.8 km NE of Copahue’s El Agrio Crater. In addition, abundant LP and volcano-tectonic (VT) signals with relatively lower magnitudes were also located in the same area. Some of the events were felt by residents of Caviahue (10 km E) and Copahue 7 km NE) in Argentina. SERNAGEOMIN raised the Alert Level to Orange (second highest level on a four-colour scale) and ONEMI updated the Yellow Alert (the middle level on a three-colour scale) for residents, noting a restriction for entering a 5-km radius from El Agrio Crater. The seismic network recorded a local M 3.1 VT earthquake at 2340 on 30 September, and a local M 3.7 VT event at 0628 on 1 October. The report also noted that 14 lower-energy events (largest was M 2.4) were recorded.

Poas | Costa Rica : OVSICORI-UNA reported that during 16-26 September sulfur dioxide emissions from Poás drifted W and NE, causing a sulfur odor in Alajuela, Heredia, San José, and Cartago. Acidic rain was recorded at the official’s house in the Poás Volcano National Park (PNVP) on 23 September and at Universidad Nacional Costa Rica (UNA) in Heredia on 26 September. At 0540 on 30 September a five-minute-long phreatic eruption ejected sediment, and produced a plume that rose 2 km above the crater rim and drifted SW. Ashfall and a sulfur odor was reported in Trojas de Sarchi and Grecia. Officials closed the PNVP because of the eruption and ongoing elevated seismicity; the park remained closed the next day.

Ulawun | New Britain (Papua New Guinea) : RVO reported that small, discrete, volcano-tectonic earthquakes at Ulawun began occurring more regularly around 1000 on 30 September; by 1130 they were frequent and by 1220 they were characterized as a swarm. The magnitude of the events overall increased with time and some were felt by residents and accompanied by booming sounds. Events were less frequent and intense during 1730-1930. Sometime afterwards RSAM values erratically increased, reaching a high of 10,000 units between 0130 and 0200 on 1 October. The Alert Level was raised to Stage 2 (the second lowest level on a four-stage scale). Periods of volcano-tectonic earthquakes slowly transformed into continuous tremor with distinct bursts of high-frequency signals marking discrete volcano-tectonic events during 0430-0500 on 1 October. During this time a new vent opened in a deep valley on the SSW flank at 700 m elevation. The eruption was described as a distinct incandescent glow formed from ejecting material rising less than 100 m above the vent. By dawn light-gray ash plumes were visible rising several hundred meters and drifting NW. Lava fountaining continued throughout the day, and gray ash plumes rose several kilometers above the vent and drifted W. RVO recommended that the Alert Level be raised to Stage 3. On 2 October lava fountains rose several hundred meters and ash-and-steam plumes rose to variable heights between 2 and 5 km, causing ashfall in Navo (W). A lava flow which emerged during the night traveled 1-2 km NW, though visibility was hindered due to weather conditions. Loud rumbling and roaring was noted. Seismicity remained high with RSAM values passing 12,000 units.

Volcanos

Global Volcanic Activity – Ongoing Activity for the week of 18 September – 24 September 2019

Aira | Kyushu (Japan) : JMA reported that incandescence from Minamidake crater (at Aira Caldera’s Sakurajima volcano) was occasionally visible at night during 17-24 September. There were 30 eruptive events, 11 of which were explosive. Plumes rose as high as 2.6 km above the crater rim, and material was ejected as far as 1.7 km from the crater. On 20 September one of the explosions produced an ash plume that rose 3.4 km above the crater rim before merging into weather clouds. Large blocks were ejected 500-700 m. The Alert Level remained at 3 (on a 5-level scale).

Ambae | Vanuatu : The Vanuatu Meteorology and Geo-Hazards Department (VMGD) lowered the Alert level for Ambae to 1 (on a scale of 0-5) on 23 September, noting that field observations on 12 August and ongoing monitoring data suggested that activity had declined and was stable. The public was warned to stay outside of the Danger Zone defined as a 2-km radius around the 2017-2018 active vents in Lake Voui.

Asosan | Kyushu (Japan) : JMA reported that ash emissions continued to be observed at Asosan, rising to 1.6, 1.1, and 0.9 km above the crater rim during 14-17, 18-20, and 21-24 September, respectively. Sulfur dioxide emissions were high at 3,600 tons per day on 17 September and 2,700 tons per day on 19 September. Ashfall was reported in downwind areas to the SW, including at the Kumamoto Regional Meteorological Observatory. The Alert Level remained at 2 (on a scale of 1-5).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 18-24 September ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 13-15 and 18 September that sent ash plumes up to 2.5 km (8,200 ft) a.s.l. and drifted E. A thermal anomaly was identified in satellite images on 15 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that Strombolian activity from vents at the bottom of Etna’s Voragine Crater (VOR) continued during 16-22 September. On 18 September guides observed intensified explosive activity at VOR characterized by the ejection of scoria and ash from several vents to heights of tens of meters. A lava flow from the cone had descended the W flank of the cone to its base, and then flowed several hundred meters S and branched into the Bocca Nuova Crater. Similar activity was observed on 19 September, though by 22 September the lava flows were cooling and Strombolian activity from VOR vents had become less frequent. Gas emissions rose from Northeast Crater (NEC); an ash emission was noted on 22 September.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 16-22 September lava continued to effuse from Karangetang’s Main Crater (S) and Dua Crater (N), traveling as far as 1.8 km down the Nanitu, Pangi, and Sense drainages on the SW and W flanks. Sometimes dense white plumes rose to 500 m above the summit. The Alert Level remained at 2 (on a scale of 1-4).

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Karymsky was visible in satellite images on 14 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Klyuchevskoy was sometimes visible in satellite images, though the temperature of the anomaly had steadily decreased over time. Gas-and-steam emissions persisted; ash was last emitted on 2 July. The Aviation colour Code was lowered to Green (the lowest on a four-colour scale) on 24 September.

Krakatau | Indonesia : PVMBG reported that Anak Krakatau’s seismic network recorded nine eruptive events during 16-22 September. A webcam at the summit recorded dense gray-to-white eruption plumes and diffuse white plumes rising 200 m from the bottom of the crater. An eruptive event at 0843 on 24 September produced a dense white-to-gray ash plume that rose around 360 m a.s.l. and drifted N. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

Merapi | Central Java (Indonesia) : PVMBG reported that the lava dome at Merapi slowly grew during 16-22 September and was an estimated 468,000 cubic meters, based on 19 September measurements from drone photos. Extruded lava fell into the upper parts of the SE flank, generating block-and-ash flows that traveled as far as 1.3 km down the Gendol drainage during 17 and 20-21 September. Diffuse white plumes rose as high as 100 m above the summit. At 1136 on 22 September the seismic network began recording signals indicating pyroclastic-flow generation, that lasted two minutes and five seconds; pyroclastic flows traveled 1.2 km down the Gendol drainage. An ash plume rose around 800 m above the summit and caused minor ashfall in areas as far as 15 km SW. Temperature increases at several points on the lava dome were recorded about one hour before the event. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.

Pacaya | Guatemala : A special report from INSIVUMEH noted that seismic activity at Pacaya continued to increase, with RSAM values reaching 8,000 units by 18 September, coincident with an intensification of explosive activity at Mackenney Crater. Explosions from a growing cone in the crater ejected material as high as 100 m above the cone. Lava effusion increased; several lava flows (300-500 m long) advanced on the N and NW flank towards Cerro Chino and produced avalanches of blocks up to 1 m in diameter from the flow fronts. Strombolian explosions during 19-24 September ejected material 5-25 m above the cone, though on 21 September material was ejected as high has 100 m. Two lava flows traveled SW on 21 September.

Poas | Costa Rica : OVSICORI-UNA reported that at 2059 on 22 September an eruptive event at Poás generated a plume that rose 3 km above the crater rim and drifted NE. During 22-23 September eruption plumes rose 1 km.

Semisopochnoi | United States : AVO lowered the Volcano Alert Level for Semisopochnoi to Advisory and the Aviation colour Code to Yellow on 18 September noting a decrease in seismic activity over the past few weeks and an absence of tremor since 15 September. Low-levels sulfur dioxide emissions persisted, and the crater lake continued to fill with water.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 13-20 September. Ash plumes drifted 200 km SW, SE, and NE during 12-15, 17, and 19 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Shishaldin | Fox Islands (USA) : AVO reported that during 18-24 September low-level tremor at Shishaldin continued to be recorded, along with elevated surface temperatures at the summit crater visible in satellite images when views were not obscured by clouds. The data suggested ongoing, slight growth of the scoria cone and lava flows within the summit crater. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Suwanosejima | Ryukyu Islands (Japan) : JMA reported that at 0704 on 16 September a very small eruptive event at Suwanosejima’s Ontake Crater generated a plume that rose 400 m above the crater rim. The Alert Level remained at 2 (on a 5-level scale).

Tangkubanparahu | Western Java (Indonesia) : PVMBG reported that the seismic network at Tangkubanparahu recorded continuous tremor during 16-22 September. A phreatic event at Ratu Crater on 17 September was accompanied by roaring. An ash plume rose as high as 40 m above the vent and steam plumes rose as high as 200 m. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.

Ubinas | Peru : During 16-22 September the number of seismic events totaled 4,356, with volcano-tectonic (VT) signals being the most numerous, averaging 567 events per day, and all having magnitudes under M 2.5. Hybrid events averaged 119 events per day. Continuous emissions of blueish gas and water vapor were recorded by the webcam rising to heights less than 1 km above the summit. Four thermal anomalies were recorded by the MIROVA system. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 10-km radius.

Volcanos

Global Volcanic Activity – Ongoing Activity for the week of 11 September – 17 September 2019

Aira | Kyushu (Japan) : JMA reported that inflation at Minamidake crater (at Aira Caldera’s Sakurajima volcano) began to be detected on 9 September and was similar to the deformation recorded just before a notable eruption on 16 June 2018. An eruption recorded at 0746 on 16 September produced an ash plume that rose 2.8 km above the crater rim and drifted SW. A series of eruptive events were recorded during 0830-1110. Deformation ceased after the events. An explosion at 0927 on 17 September generated an ash plume that rose 1 km and ejected blocks as far as 1.1 km. Two eruptive events later than day produced ash plumes that rose 1.6 km. The Alert Level remained at 3 (on a 5-level scale).

Asosan | Kyushu (Japan) : JMA reported that during 10-13 September ash plumes rose 1.6 km above Asosan’s summit crater rim. The sulfur dioxide emission rate was 1,600 tons per day on 11 September. The Alert Level remained at 2 (on a scale of 1-5).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 11-17 September ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted N, NNE, and NE. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 7-13 September that sent ash plumes up to 3 km (10,000 ft) a.s.l. and drifted S, SE, and N. Ash fell in Severo-Kurilsk on 6 September. A thermal anomaly was identified in satellite images on 8 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that Strombolian activity at Etna’s Northeast Crater (NEC) likely began on 8 September. Continuous Strombolian activity recorded between 2000 on 9 September and 0700 on 10 September produced diffuse ash emissions which quickly dissipated. The most intense part of the eruptive period occurred during 2000-2200. Minor ashfall was reported in Piedimonte Etneo, Giarre-Riposto, and Rifugio Citelli. Incandescence from the activity had significantly subsided by 0300 on 10 September, coincident with the ejection of lava fragments outside of the crater. Dilute ash puffs were continuously observed at dawn the next day. Strombolian activity ceased around 0540 and then resumed around 0800. Weather conditions hindered observations at times on 11 September but clear observations after 2000 allowed for the confirmation of continuing explosive activity at varying intensity at NEC. Ash emission from Voragine Crater began during the morning of 12 September and gradually increased in frequency. Activity further intensified at 1200 as Strombolian activity commenced and tephra ejected out of the crater was deposited at the base of Bocca Nuova Crater. Strong Strombolian explosions were felt in Zafferana Etnea, Aci S. Antonio, Pedara, and neighboring areas. Webcam and field observations on 13 September confirmed continuing activity at NEC and Voragine craters. Diffuse ash plumes rose from NEC and dispersed near the summit area. Strombolian activity at Voragine Crater ejected coarse tephra as high as 20 m above the crater rim and produced diffuse ash emissions. Impact craters from the ejected tephra were distributed mostly in the W part of the area between Bocca Nuova and Voragine craters down to 3,000 m elevation. Activity continued on 14 September. During an overflight on 15 September observers noted that a scoria cone had formed in Voragine Crater, and diffuse ash emissions continued to rise from NEC.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 9-15 September lava continued to effuse from Karangetang’s Main Crater (S) and Dua Crater (N), traveling as far as 1.5 km down the Nanitu, Pangi, and Sense drainages on the SW flank. Sometimes dense white plumes rose to 100 m above the summit. According to the Darwin VAAC an ash plume rose almost 650 m above the summit and drifted E on 11 September. The Alert Level remained at 2 (on a scale of 1-4).

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images on 10 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Krakatau | Indonesia : PVMBG reported that Anak Krakatau’s seismic network recorded five eruptive events during 9-15 September. A webcam at the summit recorded diffuse white plumes rising 150 m from the bottom of the crater, and dense gray-and-white ash plumes rising 300 m. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

Merapi | Central Java (Indonesia) : PVMBG reported that during 9-15 September the lava-dome volume at Merapi did not change and was an estimated 461,000 cubic meters, based on analyses of drone images on 8 August. Extruded lava fell into the upper parts of the SE flank, generating block-and-ash flows that traveled as far as 1.1 km down the Gendol drainage. Diffuse white plumes rose as high as 100 m above the summit. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.

Pacaya | Guatemala : A special report from INSIVUMEH noted that seismic activity at Pacaya had increased on 8 September, with RSAM values reaching 7,000 units by 13 September, coincident with increased explosive activity at Mackenney Crater. Explosions from a growing cone in the crater ejected material as high as 75 m above the cone. Lava effusion increased; lava flows advancing on the N and NW flank towards Cerro Chino were about 500 m long. Avalanches of blocks up to 1 m in diameter were produced by the flow front. Similar activity was observed during 15-16 September.

Sangeang Api | Indonesia : The Darwin VAAC reported that on 11 September a diffuse ash plume from Sangeang Api was identified in satellite images rising to 3 km (10,000 ft) a.s.l. and drifting N. The Alert Level remained at 2 (on a scale of 1-4).

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 6-9 and 12 September. Resuspended ash formed plumes that drifted 250 km ESE during 11-12 September. Satellite and webcam data recorded ash emissions and a gas-and-steam plume with some ash drifting 50 km ESE on 12 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Shishaldin | Fox Islands (USA) : Low-level lava fountaining and minor explosive activity within Shishaldin’s summit crater was last observed on 17 August and likely continued during 11-17 September; continuous tremor was recorded by the seismic network and elevated surface temperatures were visible in satellite images. The webcam possibly recorded a steam emission on 16 September. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Tangkubanparahu | Western Java (Indonesia) : PVMBG reported that phreatic events, accompanied by roaring, continued at Tangkubanparahu’s Ratu Crater during 9-15 September, though no larger eruptions were recorded. Ash-and-steam emissions rose as high as 20 m above the vent and steam plumes rose as high as 200 m. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.

Ubinas | Peru : During 10-15 September the number of seismic events at Ubinas totaled 4,093, with volcano-tectonic (VT) signals being the most numerous, averaging 572 events per day, and all having magnitudes under M 2.5. Hybrid events averaged 299 events per day. Continuous emissions of blueish gas and water vapor were recorded by the webcam rising to heights less than 1.5 km above the summit. Two thermal anomalies were recorded by the MIROVA system. An explosion at 0725 on 12 September produced a gas-and-ash plume that rose 1.5 km and affected several districts S and SE in the Moquegua region. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 10-km radius.

Volcanos

Global Volcanic Activity – New Activity for the week of 11 September – 17 September 2019

Alaid | Kuril Islands (Russia) : The Tokyo VAAC reported that on 11 September an ash plume from Alaid identified in satellite images rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SE.

Copahue | Central Chile-Argentina border : OVDAS-SERNAGEOMIN reported that a long-period (LP) earthquake at Copahue recorded at 1657 on 11 September correlated with an infrasound signal from an explosion; a gas-and-ash emission rose to low heights. A larger explosion, recorded at 2245 along with an LP earthquake, produced a plume that rose 250 m above the crater rim. Incandescent deposits around the vent were visible at night, and a 3-km-long ash deposit, covering an area of 3.4 square kilometers, was visible on the ESE flank. The Alert Level remained at Yellow (second lowest level on a four-colour scale); SERNAGEOMIN recommended no entry into a restricted area within 500 m of the crater. ONEMI maintained the Alert Level at Yellow (the middle level on a three-colour scale) for the municipality of Alto Biobío.

Nevados de Chillan | Chile : ONEMI and SERNAGEOMIN reported that during 10-17 September white-to-gray gas plumes from Nevados de Chillán’s Nicanor Crater rose 400-800 m above the rim and drifted NE, E, and SE. Explosions sometimes ejected incandescent material onto the E and SE flanks. A lava flow on the NNE flank was 100 m wide, 5 m thick, and had advanced 600 m by 14 September. The Alert Level remained at Orange, the second highest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.

Villarrica | Chile : Video from an 11 September overflight of Villarrica, conducted by the Carabineros Región de La Araucanía, showed an active cone on the crater floor. ONEMI and SERNAGEOMIN noted that the activity was consistent with the elevated seismicity detected by the seismic network during the previous few days. Seismicity and explosive activity in the crater both began decreasing on 12 September and continued a downward trend at least through 16 September. Discrete tremor signals disappeared during 15-16 September, with moderate levels of continuous tremor dominating the signal. No explosions were detected. SERNAGEOMIN lowered the Alert Level to Yellow, the second lowest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the municipalities of Villarrica, Pucón (16 km N), Curarrehue, and the commune of Panguipulli, and changed the exclusion zone for the public to a radius of 1 km around the crater.

Volcanos

Global Volcanic Activity – Ongoing Activity for the week of 4 September – 10 September 2019

Aira | Kyushu (Japan) : JMA reported that at 1549 on 3 September an explosion at Minamidake crater (at Aira Caldera’s Sakurajima volcano) generated an ash plume that rose 1.9 km above the crater rim and ejected material as far as 900 m from the vent. Very small eruptive events were detected during 6-9 September. The Alert Level remained at 3 (on a 5-level scale).

Asosan | Kyushu (Japan) : JMA reported that during 2-9 September ash plumes rose from Asosan and drifted N and NW. The sulfur dioxide emission rate was 800, 2,500, and 2,000 tons per day on 2, 6, and 9 September, respectively. The Alert Level remained at 2 (on a scale of 1-5).

Copahue | Central Chile-Argentina border : OVDAS-SERNAGEOMIN reported that seismicity at Copahue increased at 1250 on 9 September, characterized by increased amplitude of continuous tremor. Anomalies in the seismic signals suggested elevated surface activity, though cloudy weather prevented visual observations. According to the Buenos Aires VAAC diffuse steam emissions recorded by the webcam on 10 September rose to 3.5 km (11,000 ft) a.s.l. and possibly contained minor amounts of ash. The Alert Level remained at Yellow (second lowest level on a four-colour scale); SERNAGEOMIN recommended no entry into a restricted area within 500 m of the crater. ONEMI maintained the Alert Level at Yellow (the middle level on a three-colour scale) for the municipality of Alto Biobío.

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 4-10 September ash plumes from Dukono rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : KVERT reported that a thermal anomaly over Ebeko was identified in satellite images during 30-31 August. Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E, observed explosions during 30 August and 3-5 September that sent ash plumes up to 3 km (10,000 ft) a.s.l. Ash plumes drifted E and SE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that the mean amplitude of volcanic tremor at Etna had been increasing. Notably, the increase since mid-August had reached significant values by 6 September and were comparable to those values recorded just before the December 2018 eruption, and higher than those observed before the eruptive episodes during May-July 2019. Inclement weather prevented visual observations of the summit craters, though mountain guides reported characteristic sounds of Strombolian activity at the Bocca Nuova crater on 6 September. A sudden increase in volcanic tremor amplitude was recorded at 0449 on 9 September, and by 0536 Strombolian activity at Northeast Crater (NEC) was visible. At 1050 volcanic tremor amplitude again increased, with signals localized beneath NEC. Diffuse ash plumes rose from the crater and dissipated near the summit.

Ibu | Halmahera (Indonesia) : PVMBG reported that at 0936 on 4 September a gray ash plume from Ibu rose at least 300 m above the summit and drifted S. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 2-8 September lava continued to effuse from Karangetang’s Main Crater (S) and Dua Crater (N), traveling as far as 1.5 km down the Nanitu, Pangi, and Sense drainages on the SW flank. Sometimes dense white plumes rose to 200 m above the summit. According to the Darwin VAAC a diffuse ash plume rose almost 350 m above the summit and drifted SE on 7 September. The Alert Level remained at 2 (on a scale of 1-4).

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Karymsky was visible in satellite images on 5 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Krakatau | Indonesia : PVMBG reported that Anak Krakatau’s seismic network recorded six eruptive events during 2-8 September. The events were not followed by visible ash emissions, even though there were favorable weather conditions for viewing. A webcam at the summit recorded diffuse white plumes rising 100 m from the crater rim. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

Merapi | Central Java (Indonesia) : PVMBG reported that during 26 August-1 September the lava-dome volume at Merapi did not change and was an estimated 461,000 cubic meters, based on analyses of drone images on 8 August. Extruded lava fell into the upper parts of the SE flank, generating block-and-ash flows that traveled down the Gendol drainage; a block-and-ash flow traveled 2 km on 27 August. Diffuse white plumes rose as high as 80 m above the summit. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.

Semeru | Eastern Java (Indonesia) : The Darwin VAAC reported that on 10 September an ash plume from Semeru rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted WNW based on satellite images and weather models. The Alert Level remained at 2 (on a scale of 1-4).

Semisopochnoi | United States : AVO reported that low-level eruptive activity at Semisopochnoi possibly continued during 4-10 September. Seismic activity was relatively minor and characterized by intermittent low-frequency earthquakes. Satellite images were mostly cloudy, though a low-altitude steam plume drifting 50 km S was visible on 8 September. The Volcano Alert Level remained at Watch and the Aviation colour Code remained at Orange.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a daily thermal anomaly over Sheveluch’s lava dome was identified in satellite images during 30 August-6 September. Ash clouds were seen in satellite images drifting 660 km during 29 August, and 2-3 September, and 5 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Shishaldin | Fox Islands (USA) : Low-level lava fountaining and minor explosive activity within Shishaldin’s summit crater was last observed on 17 August and likely continued during 4-10 September; continuous tremor was recorded by the seismic network and moderately-elevated surface temperatures were visible in satellite images. Elevated surface temperatures on the upper SE flank suggested that minor amounts of lava spatter may have extended beyond the summit crater; clear webcam images showed no evidence of hot deposits on the upper flank the next day. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Suwanosejima | Ryukyu Islands (Japan) : JMA reported that during 30 August-6 September white plumes rose 1.2 km above the rim of Suwanosejima’s Ontake Crater and crater incandescence was visible at night. According to the Tokyo VAAC an ash plume rose 2.4 km (8,000 ft) a.s.l. and drifted W on 10 September. The Alert Level remained at 2 (on a 5-level scale).

Tangkubanparahu | Western Java (Indonesia) : PVMBG reported that during 2-8 September emissions at Tangkubanparahu’s Ratu Crater were characterized by bursts white vapor plumes. At 0724 on 4 September a dense white-to-gray plume rose about 100 m above the vent and drifted S and SW. Two large eruptive events were recorded at 1657 and 1709 on 7 September. White water vapor plumes rose to 200 m above the vent and dense black tephra plumes rose as high as 180 m. Ashfall was localized around Ratu Crater. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.

Ubinas | Peru : IGP reported that during 3-9 September three volcanic explosions were detected at Ubinas, all producing eruption plumes that rose to heights less than 2.5 km above the crater rim. The largest, and first, was recorded at 1358 on 3 September and produced significant amounts of ash and gas, affecting areas to the S and SE. After the explosions gas-and-steam plumes rose as high as 1 km. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 10-km radius.

Volcanos

Global Volcanic Activity – New Activity for the week of 4 September – 10 September 2019

Villarrica | Chile : ONEMI and SERNAGEOMIN reported that the seismic network at Villarrica recorded significant variations in seismicity beginning at 0030 on 8 September, characterized by an increase in the number of long-period (LP) events from 20 to 50 per hour. LP events ceased to be detected around 1030 and short periods of high-energy tremor began. Weather clouds prevented views of the summit crater, though the characteristics of the seismicity indicated fluctuating lava-lake activity. The increased seismicity persisted on 9 September, prompting SERNAGEOMIN to raise the Alert Level to Orange, the second highest level on a four-color scale. ONEMI has maintained an Alert Level Yellow (the middle level on a three-color scale) since 6 August for the municipalities of Villarrica, Pucón (16 km N), and Curarrehue, along with the commune of Panguipulli and stated that the public should stay at least 2 km away from the crater. On 10 September seismicity remained high; infrasound signals were recorded at a rate of 50 events per hour.

Volcanos

Global Volcanic Activity – Ongoing Activity for the week of 28 August – 3 September 2019

Aira | Kyushu (Japan) : JMA reported that during 26 August-2 September very small eruptive events were detected at Minamidake crater (at Aira Caldera’s Sakurajima volcano), though none of them were explosive. Crater incandescence was visible in webcams at night during 1-2 September. The Alert Level remained at 3 (on a 5-level scale).

Asosan | Kyushu (Japan) : JMA and the Tokyo VAAC reported that an eruptive event at Asosan was recorded at 1929 on 29 August; a plume rose 200 m above the crater rim and drifted N. During 30 August-3 September ash plumes rose as high as 250 m and drifted E, NE, N, and NW. The Alert Level remained at 2 (on a scale of 1-5).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 28 August-3 September ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted in multiple directions. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : KVERT reported that a thermal anomaly over Ebeko was identified in satellite images on 23 August. Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E, observed explosions during 27-28 August that sent ash plumes up to 3 km (10,000 ft) a.s.l. and drifted E. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Fuego | Guatemala : INSIVUMEH reported that there were multiple explosions per hour recorded at Fuego during 28 August-3 September, generating ash plumes that rose as high as 1.1 km above the crater rim and drifted 10-20 km W and SW. Explosions sometimes produced shock waves that rattled houses in nearby communities. Incandescent material was ejected 200-300 m high and caused avalanches of material that occasionally traveled long distances (reaching vegetated areas) down Seca (W), Taniluyá (SW), Ceniza (SSW), Trinidad (S), El Jute (SE), Las Lajas (SE), and Honda ravines. Ashfall was reported in several areas downwind including Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché I and II (8 km SW), Sangre de Cristo (8 km WSW), Finca Palo Verde, San Pedro Yepocapa (8 km NW), and El Porvenir (8 km ENE).

Ibu | Halmahera (Indonesia) : PVMBG reported that at 1847 on 31 August an ash plume from Ibu rose at least 800 m above the summit and drifted N. Seismicity was characterized by an explosion signal and earthquakes indicating rock avalanches. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 26 August-1 September lava continued to effuse from Karangetang’s Main Crater (S) and Dua Crater (N), traveling as far as 1.5 km SW down the Nanitu and Pangi drainages, 1.4 km down a drainage W of Pangi, and 1.8 km down the Sense drainage. Sometimes dense white plumes rose to 200 m above the summit. The Alert Level remained at 2 (on a scale of 1-4).

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images during 23-24 August along with ash plumes drifting 51 km SE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Kerinci | Indonesia : The Darwin VAAC reported that on 2 September a possible minor ash plume from Kerinci rose to an altitude of 4.9 km (16,000 ft) a.s.l. and drifted WSW, based on satellite images and weather models.

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Klyuchevskoy was sometimes visible in satellite images and that gas-and-steam emissions continued, though ash was last emitted on 2 July. The Aviation colour Code was lowered to Yellow (the second highest lowest on a four-colour scale) on 30 August.

Merapi | Central Java (Indonesia) : PVMBG reported that during 26 August-1 September the lava-dome volume at Merapi did not change and was an estimated 461,000 cubic meters, based on analyses of drone images on 8 August. Extruded lava fell into the upper parts of the SE flank, generating block-and-ash flows that traveled down the Gendol drainage; one flow traveled 2 km on 27 August. Diffuse white plumes rose as high as 80 m above the summit. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.

Nevados de Chillan | Chile : ONEMI and SERNAGEOMIN issued special reports noting as many as three explosions per day at Nevados de Chillán’s Nicanor Crater during 28 August-1 September, with each explosion associated with long-period earthquakes. The webcam recorded gas emissions that turned gray with explosions rising 160-550 m above the crater during the daytime, and explosions ejecting incandescent material onto the NNE flank at night. Plumes drifted SE, NE, and NNW. The Alert Level remained at Orange, the second highest level on a four-colour scale. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the communities of Pinto, Coihueco, and San Fabián, and stated that the public should stay at least 3 km away from the crater on the SW flank and 5 km away on the ENE flank.

Pacaya | Guatemala : INSIVUMEH reported that during 28 August-3 September Strombolian explosions at Pacaya’s Mackenney Crater ejected material as high as 30 m above the crater rim. Lava flows on the N and NNW flanks continued to advance, producing minor avalanches from the flow fronts.

Sabancaya | Peru : Instituto Geofísico del Perú (IGP) reported that an average of 26 low-to-medium intensity explosions per day occurred at Sabancaya during 26 August-1 September. Gas-and-ash plumes rose as high as 2 km above the summit and drifted SE, NW, and SW. There were 11 thermal anomalies identified in satellite data. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 12-km radius.

Sangeang Api | Indonesia : The Darwin VAAC reported that during 28 August-3 September intermittent ash plumes from Sangeang Api were identified in satellite images rising to 3 km (10,000 ft) a.s.l. and drifting N, NW, W, and SW. The Alert Level remained at 2 (on a scale of 1-4).

Santa Maria | Guatemala : INSIVUMEH reported that on most days during 28 August-3 September there were 2-4 explosions per hour detected at Santa María’s Santiaguito lava-dome complex. Ash plumes rose 700-900 m above the complex and drifted SW and W. Avalanches of material descended the E, SE, and S flanks, sometimes producing ash plumes that rose along the path of the avalanche. Ash fell in Monte Claro (S) on 31 August.

Semisopochnoi | United States : AVO reported that low-level eruptive activity at Semisopochnoi possibly continued during 28 August-3 September. Seismic activity was relatively minor and characterized by intermittent low-frequency earthquakes. Minor tremor was detected until 30 August. Satellite images were obscured by clouds. The Volcano Alert Level remained at Watch and the Aviation colour Code remained at Orange.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 22-25 August. Ash plumes on 25 August rose to 4.5-5 km (14,800-16,400 ft) a.s.l. and drifted more than 500 km NW. At 1510 on 29 August explosions produced ash plumes that rose to 10 km (32,800 ft) a.s.l. The leading part of the plume drifted W and then curved counterclockwise to the S, then E, and finally drifted 550 km N. Explosions at 1957 on 30 August produced ash plumes that rose to 7-7.5 km (23,000-24,600 ft) a.s.l. and drifted 50 km SSE. Ash plumes drifted SE at an altitude of 5.5 km (18,000 ft) a.s.l. on 3 September. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Shishaldin | Fox Islands (USA) : Low-level lava fountaining and minor explosive activity within Shishaldin’s summit crater was last observed on 17 August and likely continued during 28 August-2 September; continuous tremor was recorded by the seismic network and moderately-elevated surface temperatures were visible in satellite images. The Aviation colour Code remained at Orange and the Volcano Alert Level remained at Watch.

Tangkubanparahu | Western Java (Indonesia) : PVMBG reported that during 26 August-1 September emissions at Tangkubanparahu’s Ratu Crater were characterized by puffs of dense black ash plumes rising as high as 20 m above the vent and white vapor plumes containing minor amounts of ash rising as high as 200 m. A larger event recorded at 0930 on 31 August generated a dense black tephra plume that rose 300 m and a white steam plume that rose 600 m. Ashfall was localized around Ratu Crater. The seismic network recorded continuous tremor. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay 1.5 km away from the active crater.

Ubinas | Peru : IGP reported that during 27 August-2 September gas-and-water-vapor plumes from Ubinas rose to heights less than 1 km above the summit, and three thermal anomalies were recorded by the MIROVA system. The number of seismic events was 2,828 (all under M 2.3), with volcano-tectonic (VT) signals being the most numerous. There was a slight increase in the number of long-period, hybrid, and VT events compared to the previous week. Beginning at 2145 on 1 September a period of continuous ash emissions was recorded by the webcam. An explosion at 1358 on 3 September generated an ash plume that rose 1.3 km above the summit and drifted more than 10 km S and SE. Prior to this event, the last explosion as recorded on 22 July. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 15-km radius.

Volcanos

Global Volcanic Activity – New Activity for the week of 28 August – 3 September 2019

Stromboli | Aeolian Islands (Italy) : INGV reported that the paroxysmal eruption at Stromboli recorded at 1217 on 28 August produced an ash plume that rose 4 km above the summit. The eruption consisted of three explosions; the first two occurred at the Area C-S (South Central crater area), and the less intense third event occurred at Area N (north crater area) and ejected material onto the Sciara del Fuoco. Material from the collapse of the eruption plume contributed to the generation of a pyroclastic flow that traveled down the Sciara del Fuoco and several hundred meters out to sea. Morphological changes to Area N were evident after the paroxysm. The complex of small scoria cones, which had grown around the vents during the last few weeks, were destroyed. The NW crater rim of Area N had subsided, allowing lava flows to travel down the Sciara del Fuoco. During an overflight on 30 August volcanologists noted that Area N had collapsed and contained three vents generating Strombolian activity, and Area C-S had one large crater exhibiting Strombolian activity. Strombolian activity resumed after the paroxysm on 28 August; lava flows from Area N reached the coastline by 1945. The next day lava from Area N flowed halfway down the Sciara del Fuoco at 2123 on 29 August and shed material from the front that rolled down to the coast. A new explosive sequence at Area C-S began at 2243 and produced tephra fall in Ginostra (1.5 km from the summit). A low-intensity explosion was recorded at 2329. A lava flow from Area C-S reached the sea during the early part of 30 August. Strombolian activity persisted at moderate levels during 31 August-3 September.

Volcanos

Global Volcanic Activity – Ongoing Activity for the week of 21 August – 27 August 2019

Aira | Kyushu (Japan) : JMA reported that very small eruptive events at Minamidake crater (at Aira Caldera’s Sakurajima volcano) occasionally occurred during 19-26 August. The Alert Level remained at 3 (on a 5-level scale).

Asosan | Kyushu (Japan) : JMA reported that during 18-23 August ash plumes rose from Asosan and drifted N and NW. Crater incandescence was visible at night. An eruption recorded during 1130-1945 on 25 August generated ash plumes that drifted E. The sulfur dioxide emission rate was 1,800 tons per day on 21 August and remained high on 25 August. The Alert Level remained at 2 (on a scale of 1-5).

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, and information from PVMBG, the Darwin VAAC reported that during 21-27 August ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted mainly E, NE, N, and NW. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 17-23 August that sent ash plumes up to 3 km (10,000 ft) a.s.l. and drifted SE. A thermal anomaly was identified in satellite images on 16 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Ibu | Halmahera (Indonesia) : PVMBG reported that at 0704 on 22 August an ash plume from Ibu rose at least 800 m above the summit and drifted W. Seismicity was characterized by an explosion signal and earthquakes indicating rock avalanches. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater, and 3.5 km away on the N side.

Karangetang | Siau Island (Indonesia) : PVMBG reported that during 19-25 August lava continued to effuse from Karangetang’s Main Crater (S) and Dua Crater (N). Avalanches of incandescent material traveled 1-1.5 km SW down the Nanitu and Pangi drainages, as far as 2 km down a drainage W of Pangi, and as far as 1.8 km down the Sense drainage. Sometimes dense white plumes rose to 200 m above the summit. The Alert Level remained at 2 (on a scale of 1-4).

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that ash plumes from Karymsky were visible in satellite images drifting 500 km SW during 20-22 August. Explosions on 21 August produced ash plumes that rose to 6 km (19,700 ft) a.s.l. A thermal anomaly over the volcano was visible during 21-22 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Klyuchevskoy was visible in satellite images during 17-23 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Krakatau | Indonesia : PVMBG reported that Anak Krakatau’s seismic network recorded 27 eruptive events during 19-25 August. The events were not followed by visible ash emissions, even though there were favorable weather conditions for viewing. An eruption recorded by a summit webcam at 0755 on 22 August produced a white, gray, and black ash plume that rose 100-400 m from the crater rim and drifted N and NW. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km-radius hazard zone from the crater.

Merapi | Central Java (Indonesia) : PVMBG reported that during 19-25 August the lava-dome volume at Merapi did not change and was an estimated 461,000 cubic meters, based on analyses of drone images on 8 August. Extruded lava fell into the upper parts of the SE flank, generating block-and-ash flows that traveled as far as 1.9 km down the Gendol drainage: twice on 20 August, once each on 22 and 24 August, and 10 times during 25-27 August. At 1809 on 27 August a block-and-ash flow traveled 2 km. Diffuse white plumes rose as high as 350 m above the summit. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.

Reventador | Ecuador : IG reported that during 21-27 August seismic data from Reventador’s network indicated a high level of seismic activity, including explosions, long-period earthquakes, harmonic tremor, and signals indicating emissions. Weather often prevented views of the summit area, although during clear conditions ash-and-steam plumes were visible rising as high as 1 km above the crater rim and drifting W, NW, and N. Crater incandescence was periodically observed at night. Blocks were observed rolling 800 m down the flanks during 26-27 August.

Sangeang Api | Indonesia : The Darwin VAAC reported that during 21-26 August intermittent ash plumes from Sangeang Api were identified in satellite images rising to 3 km (10,000 ft) a.s.l. and drifting W and WNW. The Alert Level remained at 2 (on a scale of 1-4).

Semisopochnoi | United States : AVO reported that during 17-23 August seismicity at Semisopochnoi remained elevated and was characterized by periods of continuous tremor and discrete low-frequency earthquakes; seismic data went offline starting sometime on 17 August, though was available by around 22 August. Ground-coupled airwaves, indicative of explosive activity, were sometimes recorded in seismic data; an infrasound signal was recorded during 23-24 August. Cloudy weather often prevented satellite views of the volcano, though a steam plume was visible on 18 August and sulfur dioxide emissions were detected during 21-22 August. The Volcano Alert Level remained at Watch and the Aviation colour Code remained at Orange.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch’s lava dome was identified daily in satellite images during 17-23 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Suwanosejima | Ryukyu Islands (Japan) : The Tokyo VAAC reported that on 26 August a plume from Suwanosejima was visible in satellite images rising to 2.1 km (7,000 ft) a.s.l. The Alert Level remained at 2 (on a 5-level scale).

Ubinas | Peru : IGP reported that during 20-26 August blue-coloured gas plumes from Ubinas rose above the crater and eight thermal anomalies were recorded by the MIROVA system. The number of seismic events was 1,736 (all under M 2.4), and there was an increase in the magnitude and number of hybrid and long-period events. Around 1030 on 26 August an ash emission rose to heights below 2 km above the crater rim. Continuous ash emissions on 27 August were recorded by satellite and webcam images drifting S and SW. The Alert Level remained at Orange (the second highest level on a four-colour scale) and the public were warned to stay outside of a 15-km radius.