Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 12 December – 18 December 2018

Aira | Kyushu (Japan) : JMA reported that there were seven events and an additional five explosions at Minamidake crater (at Aira Caldera’s Sakurajima volcano) during 10-17 December, with ash plumes rising as high as 2 km above the crater rim and material ejected as far as 700 m. Crater incandescence was occasionally visible at night. The Alert Level remained at 3 (on a 5-level scale).

Dukono | Halmahera (Indonesia) : Based on satellite data, wind model data, and notices from PVMBG, the Darwin VAAC reported that during 14 and 16-17 December ash plumes from Dukono rose to altitudes of 1.5-2.1 km (5,000-7,000 ft) a.s.l. and drifted mainly SW, S, and SE. The Alert Level remained at 2 (on a scale of 1-4), and visitors were 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 7-14 December that sent ash plumes to 3.5 km (11,500 ft) a.s.l. Ash plumes drifted E. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Krakatau | Indonesia : PVMBG reported that events at Anak Krakatau were recorded at 1445 on 14 December and 1823 on 18 December, producing ash plumes that rose 200 and 300 m above the summit and drifted NE and E, respectively. The event on 14 December lasted 48 seconds and the ash plume was dense and black. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to remain outside of the 2-km radius hazard zone from the crater.

Kuchinoerabujima | Ryukyu Islands (Japan) : JMA reported that at 1637 on 18 December an eruption at Kuchinoerabujima’s Shindake Crater produced an ash plume that rose 2 km and then disappeared into a weather cloud. The event ejected material that fell in the crater area, and generated a pyroclastic flow that traveled 1 km W. The Alert Level remained at 3 (on a scale of 1-5).

Merapi | Central Java (Indonesia) : PVMBG reported that during 7-13 December the lava dome in Merapi’s summit crater grew at a rate of 2,200 cubic meters per day. By 13 December the volume of the dome, based on photos taken from the SE, was an estimated 359,000 cubic meters. White emissions of variable density rose a maximum of 200 m above the summit. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to remain outside of the 3-km exclusion zone.

Pacaya | Guatemala : In a special notice posted on 13 December INSIVUMEH reported that rumbling at Pacaya was heard within a radius of 8 km, and weak Strombolian explosions at Mackenney Crater ejected material as high as 50 m above the crater rim. Active lava flows were 200-300 m in length and traveled down the NW flank, generating avalanches of blocks that were as large as 1 m in diameter. The report also noted that the cone in the crater continued to grow, filling the crater, and was 75 m above the crater rim. During 15-16 December lava continued to flow NW and Strombolian explosions ejected material 5-25 m high.

Sabancaya | Peru : Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that an average of 18 explosions per day occurred at Sabancaya during 10-16 December. Long-period seismic events were recorded, and hybrid earthquakes were infrequent and of low magnitude. Gas-and-ash plumes rose as high as 2.2 km above the crater rim and drifted 40 km W and SW. MIROVA detected five thermal anomalies, and on 13 December the sulfur-dioxide gas flux was high at 3,100 tons per day. The report noted that the public should not approach the crater within a 12-km radius.

Sangay | Ecuador : IG reported that the eruption at Sangay that began on 8 August ended on 7 December after about four months of activity. The eruption was characterized by the extrusion of lava flows, and ash emissions that rose between 0.5-1.4 km (and occasionally higher than 2 km) and mainly drifted W and NW. Minor amounts of ash fell in Guayaquil on 18 September. Lava flows traveled 1-2 km down the ESE flank, and both block avalanches and possible small pyroclastic flows from the flow fronts traveled additionally as far as 7 km.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Sheveluch was identified in satellite images during 7-8 and 11-13 December. A small explosion, recorded at 1222 on 12 December, generated an ash plume that rose 6.5-6.8 km (21,300-22,300 ft) a.s.l. That same day a gas-and-steam plume, containing a small amount of ash and drifting 150 km NE, was visible in satellite data. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Turrialba | Costa Rica : OVSICORI-UNA reported semi-continuous activity at Turrialba during 11-16 December. Ash emissions rose as high as 500 m above the vent rim and drifted NW and SW during 11-12 December. Ashfall was reported in Guadalupe (32 km WSW) on 13 December. Pulsing ash emissions were visible on 13 December and caused ashfall in areas of Valle Central. During 14-16 December emissions had diffuse amounts of ash and drifted W and SW.

Veniaminof | United States : AVO reported that seismic data indicated that the eruption of lava from the cone in Veniaminof’s ice-filled summit caldera possibly paused on 6 December. Satellite data acquired on 10 December suggested lava effusion had stopped, though weak explosive activity from the vent possibly still occurred. No eruptive activity was evident in satellite and webcam images on the morning of 13 December. However, beginning in the afternoon intermittent tremor appeared and gradually became continuous. A plume, possibly containing ash, and elevated surface temperatures were identified in satellite and webcam images. A strong thermal anomaly was visible in satellite and webcam data during 14-15 December, and together with an eruption plume, was consistent with lava fountaining at the summit vent. By 16 December a lava flow was erupting from the vent. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale) and the Volcano Alert Level remained at Watch (the second highest level on a four-level scale).

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