Volcanos

Global Volcanic Activity - Ongoing Activity for the week of 31 July - 6 August 2019

Aira | Kyushu (Japan) : JMA reported that during 30 July-5 August very small eruptive events were detected at Minamidake crater (at Aira Caldera’s Sakurajima volcano), though none of them were explosive. Crater incandescence was occasionally visible in webcams at night. The Alert Level remained at 3 (on a 5-level scale).

Asosan | Kyushu (Japan) : JMA reported that increased eruptive activity at Asosan that began on 28 July continued at least through 5 August. Volcanologists confirmed that high-temperature, gray-white plumes rose from the center of Nakadake Crater during fieldwork conducted on 31 July. Grayish white plumes rose 1.3 km and 1.5 km above the crater rim on 1 and 5 August, respectively. Incandescence from the crater was visible at night. The Alert Level remained at 2 (on a scale of 1-5).

Chiles-Cerro Negro | Colombia-Ecuador : Instituto Geofísico de la Escuela Politécnica Nacional (IGEPN) and the Observatorio Vulcanológico y Sismológico de Pasto del Servicio Geológico Colombiano (SGC OVSP) jointly reported that the most recent seismic swarm below Cerro Negro de Mayasquer and Chiles volcanoes began in September 2018 and continued at least through 1 August. The swarm has consisted of 147,000 earthquakes, recorded up to the time of the report publication, mostly with magnitudes less than 3.6. Notably, at least 91 very-long-period earthquakes and 89 long-period earthquakes have been detected, indicative of a magmatic body at depth. In addition, at 0738 on 25 July a M4 earthquake was located 4 km below the summit of Chiles and felt by residents. About 850 volcano-tectonic events were recorded during 25-28 July.

Dukono | Halmahera (Indonesia) : Based on satellite and wind model data, the Darwin VAAC reported that during 31 July-6 August ash plumes from Dukono rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted mainly N 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 25-26 and 29 July, and 1 August, that sent ash plumes up to 2.5 km (8,200 ft) a.s.l. The plumes drifted in multiple directions. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that on 25 July Etna’s New Southeast Crater (NSEC) periodically emitted gas and ash. At 0630 on 27 July the seismic network detected a sudden increase in tremor amplitude, and at 0915 a new fissure opened on the S flank of NSEC. Explosive activity at the crater intensified at 1020 and a dense, ash-rich plume rose to 4.5-5 km a.s.l. and drifted E. A thin layer of ash was deposited in Giarre, Riposto and Torre Archirafi. Lava emerged from the S part of the new fissure and traveled SW and S; by 1235 the longest part of the flow had reached 2,850 m elevation and by 1330 it had reached 2,600 m elevation. Beginning at 1321 a sequence of particularly strong explosions generated ash plumes that rose as high as 7.5 km a.s.l. Explosive activity decreased around 0440 on 28 July, and lava effused from the vent at a lower rate. Starting at 0846 the Northeast Crater (NEC) occasionally emitted small plumes of red-brown ash. Explosive and effusive activity at NSEC ceased that evening. Activity during 29 July-4 August consisted of a few episodes of ash emissions at Bocca Nuova Crater and NEC.

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that on 26 July a thermal anomaly over Karymsky was visible in satellite images along with an ash plume drifting 60 km SE. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Kerinci | Indonesia : PVMBG reported that at 1248 on 31 July a gray ash emission from Kerinci rose around 800 m above the summit and drifted E and NE 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.

Klyuchevskoy | Central Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Klyuchevskoy was visible in satellite images during 26, 29, and 31 July, and 1 August. An ash emission was visible in webcam images on 1 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 10 eruptive events during 29 July-4 August. The events were not followed by visible emissions, though observations were hindered by weather conditions. 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 29 July-4 August the lava-dome volume at Merapi did not change and was an estimated 475,000 cubic meters, based on analyses of drone images. Extruded lava fell into the upper parts of the SE-flank, generating a total of four block-and-ash flows that traveled as far as 1 km down the Gendol drainage on 31 July and 4 August. Diffuse white plumes rose as high as 50 m above the summit on some days. 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 : On 6 August ONEMI and SERNAGEOMIN reported that activity at Nevados de Chillán’s Nicanor Crater increased in the previous few days, characterized by an increase in the size and occurrence of explosions. Specifically, there were 129 explosive events recorded since 3 August. Dense gas-and-ash plumes rose as high as 1.6 km above the crater rim and ejected material onto the flanks. Crater incandescence was visible at night. A lahar traveled 1.5 km NNE. The Alert Level remained at Orange, the second highest level on a four-colour scale, and residents were reminded not to approach the crater within 3 km. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the communities of Pinto, Coihueco, and San Fabián.

Nyamuragira | DR Congo : The Observatoire Volcanologique de Goma (OVG) reported that collapses of Nyamuragira’s inner crater walls observed in May 2019 continued during 1-31 July. Lava fountaining from a small cone was visible.

Nyiragongo | DR Congo : The Observatoire Volcanologique de Goma (OVG) reported that during 1-31 July the level Nyiragongo’s lava lake had dropped, making it not visible in the daytime. Incandescence from the lake continued to be visible at night. Activity also declined at a small eruptive cone that formed in the crater in 2014.

Sabancaya | Peru : Instituto Geofísico del Perú (IGP) reported that an average of 13 low-to-medium intensity explosions per day occurred at Sabancaya during 22-28 July. Gas-and-ash plumes rose as high as 2.3 km above the crater rim and drifted NE, E, and SE. There were eight thermal anomalies identified in satellite data. The report noted that the public should not approach the crater within a 12-km radius. Single explosions on 1 and 5 August produced an ash plume that drifted more than 30 km E and W, respectively.

Sangeang Api | Indonesia : The Darwin VAAC reported that during 31 July-3 August ash plumes from Sangeang Api were identified in satellite images rising to 2.4-3 km (8,000-10,000 ft) a.s.l. and drifting in multiple directions. 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 26 July-2 August. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Suwanosejima | Ryukyu Islands (Japan) : JMA reported that at 2331 on 1 August an explosion at Suwanosejima’s Ontake Crater ejected blocks 400 m from the crater. Weather clouds prevented visual confirmation of an ash plume. Crater incandescence was sometimes visible at night. The number of volcanic earthquakes increased on 4 August and four explosions were recorded on 5 August. The Alert Level remained at 2 (on a 5-level scale).

Villarrica | Chile : ONEMI and SERNAGEOMIN reported that on 6 August the Alert Level for Villarrica was raised to Yellow, the second lowest level on a four-colour scale, reflecting the recent increase in minor Strombolian activity ejecting spatter onto the flanks near the rim during the past weeks.