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.

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