Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 24 October - 30 October 2018

Aira | Kyushu (Japan) : JMA reported that during 22-26 October seven events at Minamidake crater (at Aira Caldera’s Sakurajima volcano) produced eruption plumes that rose as high as 1.6 km above the crater rim. Small scale events were occasionally detected through 29 October. The Alert Level remained at 3 (on a scale of 1-5).

Bezymianny | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Bezymianny was identified in satellite images during 20 and 22-25 October. Gas-and-steam emissions continued to rise from the crater. The Aviation colour Code remained at Yellow (the second lowest level on a four-colour scale).

Dukono | Halmahera (Indonesia) : Based on satellite data, wind model data, and notices from PVMBG, the Darwin VAAC reported that during 24-28 October ash plumes from Dukono rose to altitudes of 1.5-1.8 km (5,000-6,000 ft) a.s.l. and drifted E and NE.

Ebeko | Paramushir Island (Russia) : Volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, observed explosions during 19-26 October that sent ash plumes to 4.7 km (15,400 ft) a.s.l. Ash plumes drifted eastward, and caused ashfall in Severo-Kurilsk during 19-20 and 23-24 October; ash plumes drifted about 80 km E on 20 October. A thermal anomaly was visible in satellite images on 24 October. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Kadovar | Papua New Guinea : The Darwin VAAC reported that during 29-30 October intermittent ash plumes from Kadovar rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted SW, S, and SE.

Karymsky | Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was last identified in satellite images on 28 September, and an ash plume was last visible on 30 September. The volcano was either quiet or obscured by weather clouds during 1-25 October. On 26 October the Aviation colour Code was lowered to Yellow (the second lowest level on a four-colour scale).

Krakatau | Indonesia : Based on satellite data, the Darwin VAAC reported that during 24-28 October ash plumes from Anak Krakatau rose to altitudes of 0.9-2.1 km (3,000-7,000 ft) a.s.l. and drifted SW, NW, and N. The Alert Level remained at 2 (on a scale of 1-4); residents and visitors were warned not to approach within 2 km of the crater.

Merapi | Central Java (Indonesia) : PVMBG reported that during 19-25 October the lava dome in Merapi’s summit crater grew slowly at a rate of 6,100 cubic meters per day, similar to the previous week. By 21 October the volume of the dome, based on photos from the SE sector, was an estimated 219,000 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.

Nevado del Ruiz | Colombia : Servicio Geológico Colombiano’s (SGC) Observatorio Vulcanológico y Sismológico de Manizales reported that during 24-30 October seismicity at Nevado del Ruiz continued to indicate unrest. Seismicity increased during 26-27 October, with signals concentrated in an area 4.6 km WSW of Arenas Crater at depths of 4-6 km. Plumes of water vapor, ash, and gas continued to rise from the volcano, and on 26 October a plume rose as high as 1.5 km above the crater rim. A weak thermal anomaly was identified in satellite data. The Alert Level remained at 3 (Yellow; the second lowest level on a four-colour scale).

Piton de la Fournaise | Reunion Island (France) : OVPF reported that on 24 October satellite observations of Piton de la Fournaise suggested minimal change to the lava-flow field. During 25-26 October a breakout from the main tube emerged about 1 km downstream from the vent and remained visible through 28 October. Weather conditions prevented views on 29 October.

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 22-28 October. Hybrid earthquakes were infrequent and of low magnitude, and long-period events were detected. Gas-and-ash plumes rose as high as 3.4 km above the crater rim and drifted 40 km SE, E, and NE. MIROVA detected five thermal anomalies, and on 27 October the sulfur-dioxide gas flux was high at 2,671 tons per day. The report noted that the public should not approach the crater within a 12-km radius.

Semisopochnoi | United States : AVO reported that an eruptive event at Semisopochnoi began at 2047 on 25 October based on seismic data; strong volcanic tremor lasted about 20 minutes and was followed by 40 minutes of weak tremor pulses. A weak infrasound signal was detected by instruments on Adak Island (260 km SE). The Aviation colour Code was raised to Orange (the second highest level on a four-colour scale) and Volcano Alert Level was raised to Watch (the second highest level on a four-level scale). A dense meteorological cloud deck prevented observations below 3 km (10,000 ft) a.s.l.; a diffuse cloud was observed in satellite data rising briefly above the cloud deck, though it was unclear if it was related to eruptive activity. Tremor ended after the event, and seismicity returned to low levels. Small explosions were detected by the seismic network at 2110 and 2246 on 26 October and 0057 and 0603 on 27 October. No ash clouds were identified in satellite data, but the volcano was obscured by high meteorological clouds. Additional small explosions were detected in seismic and infrasound data during 28-29 October; no ash clouds were observed in partly-cloudy-to-cloudy satellite images.

Sheveluch | Central Kamchatka (Russia) : KVERT reported that a weak thermal anomaly over Sheveluch was identified in satellite data on 20, 22, and 25 October; weather clouds prevented views on the other days during 19-26 October. Moderate levels of gas-and-steam emissions rose from the volcano. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Turrialba | Costa Rica : OVSICORI-UNA reported that when weather conditions allowed for observations gas and periodic ash emissions rising from Turrialba were recorded by the webcam during 25-30 October. An event at 0134 on 26 October produced an ash plume that rose 500 m above the crater rim and drifted NE, causing ashfall in the neighborhoods of Coronado (San José, 35 km WSW) and San Isidro de Heredia (Heredia, 38 km W). Events at 0231 on 29 October and 1406 on 30 October produced plumes that rose 500 m and drifted NW and W respectively.

Veniaminof | United States : AVO reported that the eruption from the cone in Veniaminof’s ice-filled summit caldera, continued during 24-30 October. Satellite data showed elevated surface temperatures from minor lava fountaining and flows. Low-amplitude continuous tremor was detected. The webcam in Perryville, 35 km SE, periodically recorded diffuse ash emissions that often rapidly dissipated; minor ashfall was recorded in Perryville on 25 October. Based on satellite data acquired on 25 October the lava flows had traveled as far as 1.2 km from the vent, and the area of the flow field had doubled in the past month. Fractures in the ice sheet adjacent to the lava flow continued to grow due to meltwater flowing beneath the ice sheet. 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).