Roundup of Global Volcanic Activity – New Activity for the Week 7 July – 13 July 2021
Bagana – Bougainville (Papua New Guinea) : Based on satellite and wind model data, the Darwin VAAC reported that on 9 July an ash plume from Bagana rose to 1.8 km (6,000 ft) a.s.l. and drifted W.
Krakatau – Indonesia : The Darwin VAAC reported that on 7 July ash plumes from Anak Krakatau rose to 1.5 km (5,000 ft) a.s.l. and drifted NW.
Pavlof – United States : At 1140 on 9 July AVO raised the Volcano Alert Level and Aviation colour Code at Pavlof to Advisory and Yellow, respectively, noting that seismicity had increased during the previous 16 hours and was characterized by near-continuous tremor. Seismicity decreased and was more periodic during 10-13 July, but remained above background levels.
Sarychev Peak – Matua Island (Russia) : SVERT reported that on 29 June and 1 July brief ash emissions from Sarychev Peak rose to 3 km (10,000 ft) a.s.l. A weak thermal anomaly identified in satellite data persisted through 12 July; SVERT lowered the Alert Level to Green (the lowest level on a four-colour scale).
Suwanosejima – Ryukyu Islands (Japan) : JMA reported that 96 explosions at Suwanosejima’s Ontake Crater produced eruption plumes that generally rose 2-2.4 km above the crater rim during 5-12 July. Large volcanic bombs were ejected mainly 400 m from the crater and crater incandescence was visible nightly. Eruption sounds were sometimes heard in Toshima village (4 km SSW). An explosion at 0439 on 8 July ejected large bombs 800 m NW and an explosion at 1319 on 12 July produced an ash plume that rose 3 km. The Alert Level remained at 3 and the public was warned to stay 2 km away from the crater.
Taal – Luzon (Philippines) : PHIVOLCS reported that an eruption at Taal continued during 7-13 July. A series of short-lived phreatomagmatic explosions were recorded at 0518, 0847, 0915, 0926, 1156, and 2141 on 7 July and jetted ash plumes as high has 700 m. Another series was recorded at 0647, 1806, 2121, 2150 on 8 July and 0259 on 9 July, jetting ash 200 m high. During 7-13 July daily plumes of steam and sulfur dioxide gas rose 1-1.5 km from the lake and drifted NW, W, and SW. Sulfur dioxide emissions averaged 4,149-11,397 tonnes/day. Low-level background tremor continued with as many as 185 volcanic earthquakes and 44 low-frequency volcanic earthquakes recorded per day. There were also 5-176 daily episodes of volcanic tremor, each lasting between 1 and 97 minutes. The network also detected 2-10 daily hybrid earthquakes during 6-9 July. The DROMIC report stated that 10,408 people were in evacuation centers or private residences by 12 July. The Alert Level remained at 3 (on a scale of 0-5) and PHIVOLCS reminded the public that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ) and to not enter the high-risk barangays of Agoncillo and Laurel. Activities on Taal Lake were strictly prohibited.
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