Roundup of Global Volcanic Activity – Ongoing Activity for the week of 31 October – 6 November 2018

Aira | Kyushu (Japan) : JMA reported that at 1022 on 30 October an event at Minamidake crater (at Aira Caldera’s Sakurajima volcano) generated a plume that rose 1 km above the crater rim. Two explosions occurred during 2-5 November; the larger of the two sent a plume to 2.6 km and ejected material as far as 700 m from the crater. 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 30-31 October ash plumes from Dukono rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted W and N.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 26 October-2 November that sent ash plumes to 3.7 km (12,400 ft) a.s.l. Ash plumes drifted in multiple directions and caused ashfall in Severo-Kurilsk during 29-31 October. A thermal anomaly was visible in satellite images on 24 and 29 October. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Etna | Sicily (Italy) : INGV reported that during 29 October-4 November activity at Etna was characterized by gas emissions at the summit craters, with periodic Strombolian activity from vents in Bocca Nuova, Northeast Crater (NEC), SE Crater (SEC), and New Southeast Crater (NSEC). Strombolian explosions at NSEC were interspersed with long pauses from a few minutes to a few hours. The explosions sometimes produced ash emissions that quickly dispersed; ashfall was deposited around the crater and in the Valle del Bove. Strombolian activity and gas emissions were characteristic of the N vent in the W part of Bocca Nuova’s (BN-1) crater floor. Spattering from the southernmost vent was also visible, as well as gas emissions. Gas emissions at Voragine Crater from a vent on the E rim of the crater were less intense compared to previous months. NEC activity was characterized by Strombolian explosions sometimes accompanied by minor ash emissions.

Fuego | Guatemala : INSIVUMEH and CONRED reported an increase in seismicity and in the number of explosions at Fuego on 31 October. Ash plumes during 31 October-5 November rose 1 km above the summit and drifted 15 km W and SW. Ashfall was reported in areas downwind including Morelia (9 km SW), Santa Sofia (12 km SW), Sangre de Cristo (8 km WSW), Panimaché (8 km SW), and San Pedro Yepocapa (8 km NW). By 2 November a lava flow had traveled 300 m down the Ceniza (SSW) drainage, and by 4 November lava flows 600 m long descended the Ceniza and Taniluyá (SW) drainages. Explosions on 4 November produced shock waves that rattled nearby structures, and on 5 November ejected incandescent material 200 m high. INSIVUMEH reported another increase of activity on 6 November characterized by a period of constant explosions, and ash plumes rising over 1 km and drifting 20 km W and SW. Ashfall was reported in multiple areas including Panimaché, El Porvenir, Morelia, Santa Sofia, Sangre de Cristo, Finca Palo Verde, and San Pedro Yepocapa. Incandescent material was ejected 200-300 m high and caused avalanches that reached vegetated areas in the Seca and Taniluyá drainages. A 1-km-long lava flow was active in the Ceniza drainage. Shock waves from explosions vibrated local houses.

Krakatau | Indonesia : PVMBG reported that a 37-second-long event at Anak Krakatau at 0223 on 6 November generated an ash plume that, based on a ground observation, rose 500 m and drifted N. At 1000 a dense ash plume rose 600 m above the summit and drifted N. The Alert Level remained at 2 (on a scale of 1-4); residents and visitors were warned not to approach the volcano within 2 km of the crater.

Merapi | Central Java (Indonesia) : PVMBG reported that during 26 October-1 November the lava dome in Merapi’s summit crater grew slowly at a rate of 2,900 cubic meters per day, slower than the previous week. By 31 October the volume of the dome, based on photos from the SE sector, was an estimated 248,000 cubic meters. White emissions of variable density rose a maximum of 50 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.

Nevados de Chillan | Chile : Servicio Nacional de Geología and Minería (SERNAGEOMIN) Observatorio Volcanológico de Los Andes del Sur (OVDAS) and ONEMI reported the continuing, slow growth of the lava dome in Nevados de Chillán’s Nicanor Crater during 30 October-6 November. Seismicity was characterized by moderate levels of long-period and tremor events, often associated with explosion signals. Gas emissions persisted, and sometimes contained ash. Periodic explosions sometimes ejected material that was deposited around the crater. At night incandescence emanated from the lava dome as well as from ejected ballistics. 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.

Piton de la Fournaise | Reunion Island (France) : OVPF reported that seismicity associated with the eruption at Piton de la Fournaise that began on 15 September had ceased by 1 November and no further signs of activity were recorded.

Popocatepetl | Mexico : CENAPRED reported that each day during 31 October-6 November there were 89-192 steam-and-gas emissions from Popocatépetl, some of which contained minor amounts of ash. Periods of volcanic tremor were detected almost daily. Explosions at 1638 and 1727 on 3 November ejected material NE and generated plumes that rose 1.5 and 1.6 km above the crater rim, respectively. The Alert Level remained at Yellow, Phase Two (middle level on a three-colour scale).

Rincon de la Vieja | Costa Rica : OVSICORI-UNA reported that an eruptive sequence at Rincón de la Vieja began at 1945 on 4 November and consisted of at least three two-minute-long episodes. Weather conditions prevented webcam views and estimates of plume heights. The next day at 1511 a plume of water vapor and diffuse gas, recorded by a webcam and visible to residents to the N, rose about 100 m above the crater rim and drifted W.

Sabancaya | Peru : Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that an average of 30 explosions per day occurred at Sabancaya during 29 October-4 November. Hybrid earthquakes were infrequent and of low magnitude. Gas-and-ash plumes rose as high as 3.4 km above the crater rim and drifted 40 km W, SW, and S. MIROVA detected seven thermal anomalies, and on 2 November the sulfur-dioxide gas flux was high at 2,300 tons per day. The report noted that the public should not approach the crater within a 12-km radius.

Santa Maria | Guatemala : CONRED and INSIVUMEH reported that the number of avalanches at Santa María’s Santiaguito lava-dome complex increased on 2 November. The avalanches traveled long distances from the crater, down the S and SE flanks, to the volcano’s base. Some avalanches generated ash plumes. Explosions during 2-6 November produced ash plumes that rose 500-800 m above the crater rim and drifted SW, causing local ashfall. Avalanches descended the SE and NE flanks during 4-5 November.

Semisopochnoi | United States : AVO reported that two small explosions at Semisopochnoi were detected in seismic and infrasound data on 31 October. Intermittent seismic tremor was recorded on 1 November but later that day the satellite link that transmits seismic data failed. Weather clouds obscured views of the volcano during 31 October-4 November. Nothing was observed in satellite data during 5-6 November. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale) and Volcano Alert Level remained at Watch (the second highest level on a four-level scale).

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Sheveluch was identified in satellite data during 31 October-2 November. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Turrialba | Costa Rica : On 1 November OVSICORI-UNA reported that since 24 October emissions at Turrialba were continuous with plumes rising 500 m above the crater rim. In addition, seismicity was characterized by banded volcanic tremor, long-period earthquakes, and low-amplitude volcano-tectonic earthquakes. Passive ash emissions were visible during 1-6 November. A 70-minute-long event began at 0530 and generated plumes that rose 500 m and drifted SW. Several short-duration (2-3 minutes) events were recorded at 1523 and 1703 on 2 November and at 0109 on 3 November; they generated ash plumes that rose 500 m. Ashfall was reported in Coronado. Seismic activity remained high, with moderate-to-high amplitude banded tremor. At 0620 on 5 November a plume rose 600 m and drifted NW.

Veniaminof | United States : AVO reported that the eruption from the cone in Veniaminof’s ice-filled summit caldera, continued during 31 October-6 November. Satellite data showed elevated surface temperatures from minor lava spattering and flows. Low-amplitude continuous tremor was recorded. The webcam in Perryville, 35 km SE, periodically recorded diffuse ash emissions and incandescence from the cone. Based on a pilot observation and satellite data, a diffuse ash plume rose to 4.3 km (14,000 ft) a.s.l. and drifted E on 5 November. 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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