Volcano World

KVERT da的报道ily thermal anomaly over Bezymianny was identified in satellite images during 20-26 October. Dates are UTC; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Unrest continued at Bogoslof during 25-31 October with numerous daily earthquakes recorded in seismic data. No additional signs of unrest were recorded in satellite data. The Volcano Alert Level remained at Advisory (the second level on a four-level scale) and the Aviation Color Code remained at Yellow (the second color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

PHIVOLCS reported that increased seismicity at Bulusan that began on 14 October continued. The seismic network recorded a total of 121 volcanic earthquakes from 0500 on 14 October to 1500 on 25 October. Out of those, 37 were volcano-tectonic events associated with rock fracturing and were located at depths of 1-9 km beneath the NW and SE flanks of the volcano. Ground deformation data from electronic tiltmeter stations continued to record inflation at the S flank, first detected in February, and at the NE flank since September. The Alert Level was raised to 1 (the second level on a scale of 0-5) and PHIVOLCS reminded the public not to enter the 4-km-radius Permanent Danger Zone (PDZ) and to be vigilant within the 2-km Extended Danger Zone (EDZ) on the SE flank.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

The Tonga Geological Services reported that the eruption at Home Reef was ongoing. A total of nine eruptive events were detected in satellite data during 21-30 October. The Aviation Color Code remained at Yellow (the second level on a four-color scale) and mariners were advised to stay 4 km away from the island.

Source: Tonga Geological Services, Government of Tonga

According to a news source, an eruption at Ioto (Iwo-jima) occurred at a vent located about 1 km off the coast of Okinahama, on the SE side the island. During an overflight on 30 October observers recorded explosions every few minutes that ejected dark material about 20 m above the ocean. Ejecta from the vent built a black-colored island and floating pumice was present around the island.

Source: The Mainichi Daily News

KVERT reported that the Strombolian eruption at Klyuchevskoy continued during 20-29 October and a daily bright thermal anomaly was identified in satellite images. Lava fountains sometimes rose as high as 500 m above the summit and fed lava flows that descended the Apakhonchichsky and Kozyrevsky drainages on the SE and S flanks. Phreatic explosions were sometimes generated from the interaction with lava and glaciers on the flanks and caused collapses of older deposits in the drainages. Plumes of the previously deposited ash generally rose as high as 7 km (23,000 ft) a.s.l. and drifted 280 km NE, E, and SE during 22-29 October, though on 23 and 29 October plumes rose as high as 8 km (26,200 ft) a.s.l. Scientists at the Kamchatka Volcanological Station visited the volcano on 28 October and noted that the cinder cone at the summit had grown. They also observed advancing lava on the E flank that extended about 2 km from the summit to 2,700 m elevation, incandescent material being ejected 500 m above the crater, and avalanches in the Apakhonchichsky drainage. Ash plumes rose more than 2 km. Activity intensified on 31 October. Ash plumes were identified in satellite images rising as high as 10 km (32,800 ft) a.s.l., prompting KVERT to raise the Aviation Color Code to Red (the highest level on a four-color scale). Ash plumes had drifted as far as 1,300 km SSE. Dates and times are in UTC; specific events are in local time where noted.

Sources: Kamchatka Volcanological Station,Kamchatkan Volcanic Eruption Response Team (KVERT)

IMO reported that an intense earthquake swarm on the Reykjanes Peninsula began on 24 October. By 1700 on 26 October more than 4,000 earthquakes had been located at depths of 2-6 km. A total of 14 earthquakes had a magnitude over M 3; the largest event, a M 4.5, was recorded at 0818 on 25 October. Most of the activity occurred between Stra-Skogafell and an area NE of Eldvrp. No ground deformation was recorded, though a single GPS station (FEFC), E of Festarfjall, recorded localized movement to the SE. During 25-26 October the displacement recorded by the FEFC station totaled about 2 cm and movement was also detected at a station in Selatangar. The swarm continued and by 1400 on 27 October more than 5,800 earthquakes had been recorded; a M 4 earthquake occurred at 0402 on 27 October and was located about 2 km N of Grindavk. Seismicity decreased considerably by 1330 on 28 October, though the swarm was ongoing with a total of more than 7,000 earthquakes. Uplift centered around Svartsengi, 1.5 km NW of Mt. Thorbjorn, was clearly evident in satellite radar and GPS data. The uplift had begun at some point the previous day and likely signified a magmatic intrusion at depth. IMO raised the Aviation Color Code for Reykjanes to Yellow (the second level on a four-color scale) at 1518 on 28 October. During 1130 on 29 October to 1130 on 30 October about 1,300 earthquakes occurred at depths of 2-4 km. The largest event was a M 2.7 at 1140 on 29 October. Uplift continued during 28-31 October, though the rates began to decrease. Modeling suggested that magma was accumulating at a depth of about 4 km. An earthquake swarm began at 0840 on 31 October and lasted about two hours. The events were located at depths of 1.5-5 km and indicted that magma was moving.

Source: Icelandic Meteorological Office (IMO)

PVMBG reported that daily white emissions rose 50-100 m above Slamet?s summit and drifted S and W during 25-30 October. The Alert Level was lowered to 1 (on a scale of 1-4) on 30 October and the public was warned to stay 2 km away from the summit crater.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

JMA reported ongoing activity at Minamidake Crater (Aira Caldera?s Sakurajima volcano) during 23-30 October, with incandescence at the crater observed nightly. An eruptive period was recorded during 0346-0430 on 24 October; at 0346 a notable ash plume rose as high as 3.4 km above the crater rim and drifted E and ejected large blocks 1-1.3 km from the crater rim. At 0416 an ash plume rose 2.1 km above the crater rim and drifted E. A large amount of ashfall, likely from those events, was observed in Kurokami Town during a field survey later that day. Sulfur dioxide emissions were high on 25 October, averaging 2,200 tons per day. During an aerial observation on 25 October scientists noted that the N side of Showa Crater had slightly enlarged compared to the previous observations on 8 March. A high-temperature geothermal area on the Minamidake Crater floor was also visible. Periods of inflation were recorded in deformation data during 0000-1400 on 26 October and 0100-1600 on 28 October. An eruptive event at 0116 on 30 October produced an ash plume that rose 1 km above the crater rim and drifted N. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 km away from both craters.

Source: Japan Meteorological Agency (JMA)

瓦努阿图气象和地质灾害(VMGD) reported ongoing volcanic earthquakes and tremors at Ambrym during October. Volcanic activity increased for a few hours during 22-23 October and diffuse gas emissions were detected in satellite data on 23 October. The Alert Level was lowered to 1 (on a scale of 0-5) on 28 April. VMGD warned the public to stay outside of Permanent Danger Zone A, defined as a 1-km radius around Benbow Crater and a 2-km radius around Marum Crater, and additionally to stay 500 m away from the ground cracks created by the December 2018 eruption.

Source: Vanuatu Meteorology and Geo-Hazards Department (VMGD)