Volcanos

Roundup of Global Volcanic Activity – Ongoing Activity for the week of 4 April - 10 April 2018

Agung | Bali (Indonesia) : PVMBG reported that an event at Agung at 1737 on 5 April generated an ash plume that rose 500 m above the crater rim and drifted W. Seismicity was dominated by high- and low-frequency earthquakes. The Alert Level remained at 3 (on a scale of 1-4) and the exclusion zone continued at a 4-km radius.

Aira | Kyushu (Japan) : JMA reported that there were two events and 10 explosions at Minamidake crater (at Aira Caldera’s Sakurajima volcano) during 2-9 April. Tephra was ejected as far as 1.1 km from the crater, and plumes rose as high as 3.4 km above the crater rim. An event at Showa Crater generated a plume that rose 1.3 km. An explosion at 0909 on 9 April at Minamidake crater ejected large boulders 1.3 km, and produced a plume that rose 1 km. The Alert Level remained at 3 (on a 5-level scale).

Bezymianny | Central Kamchatka (Russia) : KVERT reported that a thermal anomaly over Bezymianny was identified in satellite images during 29-30 March and 2-3 April. The Aviation colour Code remained at Yellow.

Cleveland | Chuginadak Island (USA) : AVO reported that seismic and infrasound sensors recorded a small explosion at Cleveland at 0355 on 4 April. A subsequent satellite image indicated that hot material ejected from the event was deposited on the W flank, possibly reaching the coastline. A small ash cloud drifted SW at or below 4.6 km (15,000 ft) a.s.l. The Aviation colour Code was raised to Orange and the Volcano Alert Level was raised to Watch. Hours later, a small, short-duration seismic event coupled with satellite data suggested a small ash emission. The Alert level was lowered back to Yellow/Advisory on 6 April due to no further signs of activity.

Copahue | Central Chile-Argentina border : According to ONEMI, OVDAS-SERNAGEOMIN reported that during 1-31 March there were 83 volcano-tectonic events recorded at Copahue, and 204 earthquakes indicting fluid movement. Tremor levels increased on 24 March, the same day as the phreatic explosion, though by the next day decreased to baseline levels. Webcams recorded gas plumes rising from El Agrio crater as high as 1 km. During an overflight on 3 April scientists observed the crater lake, and continuous white gas plumes rising almost 400 m. The Alert Level remained at Yellow (second highest level on a four-colour scale); SERNAGEOMIN recommended no entry into a restricted area within 1 km of the crater. ONEMI maintained an Alert Level Yellow (the middle level on a three-colour scale) for the municipality of Alto Biobío.

Dukono | Halmahera (Indonesia) : Based on analyses of satellite imagery, wind model data, and notices from PVMBG, the Darwin VAAC reported that during 4-10 April 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.

Ebeko | Paramushir Island (Russia) : Based on observations by volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 31 March-6 April generated ash plumes that rose as high as 2.7 km (8,900 ft) a.s.l. The Aviation colour Code remained at Orange (the second highest level on a four-colour scale).

Fuego | Guatemala : INSIVUMEH reported that during 7-10 April explosions at Fuego generated ash plumes that rose as high as 1.1 km and drifted 10-15 km SW and S. Sometimes the explosions were accompanied by weak shock waves. Incandescent material was ejected as high as 200 m above the crater rim, and generated avalanches of material in the Seca (Santa Teresa, W), Cenizas (SSW), Las Lajas (SE), and Trinidad (S) ravines. During 9-10 April ash fell in areas downwind including in Santa Sofía (12 km SW), Morelia (9 km SW), Panimaché (8 km SW), Sangre de Cristo (8 km WSW), and San Pedro Yepocapa (8 km NW).

Kilauea | Hawaiian Islands (USA) : During 4-10 April HVO reported that the lava lake continued to rise, fall, and spatter in Kilauea’s Overlook crater. Surface lava flows were active above Pulama pali. Webcams recorded spattering from a small lava pond in a pit on the W side of Pu'u 'O'o Crater. The lava flow from a vent on the SE part of the crater floor continued to expand through 6 April. A rockfall at 1028 on 6 April triggered an explosion in the lava lake, damaging the webcam power system on the crater rim.

Mayon | Luzon (Philippines) : PHIVOLCS reported that during 4-10 April white steam plumes from Mayon drifted WNW, WSW, and SW. Crater incandescence was visible at night. The sulfur dioxide flux was 899 tonnes/day on 5 April. Tiltmeter data recorded deflation since 20 February despite short-term episodes of inflation at the lower and middle flanks. Precise leveling data showed deflation during 22-29 March relative to surveys conducted during 10-19 March. Overall ground deformation data suggested inflation compared to baseline levels. The Alert Level remained at 2 (on a 0-5 scale) and PHIVOLCS reminded residents to stay away from the 6-km-radius Permanent Danger Zone and the 7-km Extended Danger Zone on the SSW and ENE flanks.

Pacaya | Guatemala : INSIVUMEH reported that during 7-10 April Strombolian explosions at Pacaya’s Mackenney Crater ejected material as high as 40 m above the crater rim. Lava flows had traveled 250 m down the NW flank, 200 m down the W flank, and 150 m down the SW flank.

Sabancaya | Peru : Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that explosive activity at Sabancaya was similar compared to the previous week; explosions averaged 15 per day during 2-8 April. Seismicity was dominated by long-period events, with signals indicating emissions. Gas-and-ash plumes rose as high as 3.2 km above the crater rim and drifted 30 km NE, SE, and S. Ashfall was reported in Achoma (25 km NE), Chivay (36 km NE), and Huanca. The MIROVA system detected three thermal anomalies. The report noted that the public should not to approach the crater within a 12-km radius.

Suwanosejima | Ryukyu Islands (Japan) : Based on JMA notices and satellite data, the Tokyo VAAC reported that during 4-6 and 9 April explosions at Suwanosejima produced plumes that rose 1.2-2.4 km (4,000-8,000 ft) a.s.l. and drifted N, NE, and E.

Turrialba | Costa Rica : OVSICORI-UNA reported that events at Turrialba at 1230 on 5 April and 0609 on 9 April generated plumes that rose 500 and 300 m above the crater rim, and drifted S and W, respectively.