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.

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