Volcanos

Roundup of Global Volcanic Activity – New Activity for the week 13 April – 19 April 2022

Bezymianny – Central Kamchatka (Russia) : KVERT reported that the effusive eruption at Bezymianny continued during 8-15 April, along with incandescence at the lava dome, avalanches descending the SE flank, and steam-and-ash emissions. A daily thermal anomaly over the dome was identified in satellite images.

Edgecumbe – Southeastern Alaska (USA) : AVO stated that a seismic swarm beneath Kruzof Island near Edgecumbe began at about 0200 on 11 April, and by 15 April several hundred earthquakes had been recorded. The number of events was unusual for that volcano. The magnitudes were generally M 1.7 or smaller, though a M 2.8 was detected on 11 April. The events were located at depths of less than 10 km, though the exact locations were difficult to constrain due to the lack of a local seismic network on the island; the closest station was in Sitka, 25 km E. The source of the swarm was unknown, and related either to tectonic processes or volcanic unrest, or a combination of both.

Karymsky – Eastern Kamchatka (Russia) : KVERT reported that a thermal anomaly over Karymsky was visible in satellite images on 9 and 11-12 April; the volcano was quiet or obscured by clouds on the other days during 8-15 April. Explosions produced ash plumes that rose to 6 km (19,700 ft) a.s.l. and drifted SSW, based on satellite data acquired at 0810 on 20 April, local time. Explosions continued and within an hour produced larger ash plumes that rose 9.8-10 km (32,100-32,800 ft) a.s.l. and drifted almost 30 km NE.

Poas – Costa Rica : OVSICORI-UNA reported that submarine fumaroles in the S part of Poás’s Boca A lake and subaerial fumaroles along the E margins continued to produce low-temperature gas emissions during 13-19 April. The lake water continued to convect, and was light gray in color, since the phreatic explosion that had occurred on 6 April at “Orange Fumarola” located in a fumarolic field along the inner N crater wall. For a period of time on 17 April a gas monitoring station in Coronado measured a higher concentration of sulfur dioxide aerosols, between 8.5 and 17.6 micrograms of gas per cubic meter of ambient air, which was higher than the daily average of 6.7. Some residents reported respiratory discomfort such as sneezing, coughing, and shortness of breath.

Krakatau – Sunda Strait : PVMBG reported that several ash emissions from Anak Krakatau were visible in webcam images and described by observers during 15 and 17-19 April. The ash plumes were variably whitish gray, gray, and black, with all but one characterized as dense. Events at 0327, 1034, and 1837 on 15 April produced ash plumes that rose 0.7-1 km above the summit and drifted SW. Ash plumes at 0925, 1830, and 2215 on 17 April rose 500-800 m above the summit and drifted SW; Strombolian activity produced the ash plume at 1830. On 18 April events at 0358, 0419, 0714, 1246, 1330, and 1558 generated ash plumes that rose as high as 2 km and drifted SW. Ash plumes were visible on 19 April, rising 50-500 m above the summit and drifting SE and NE.

Ruang – Sangihe Islands : PVMBG reported that at least 121 deep volcanic earthquakes at Ruang were recorded during 1-16 April, though the number of those events began to increase on 7 April. No visible changes to the crater were noted, but weather conditions sometimes prevented views. Seismicity significantly changed on 16 April, characterized by 50 deep volcanic earthquakes, two local tectonic earthquakes, and four felt earthquakes.

Ruapehu – North Island (New Zealand) : On 20 April GeoNet reported that elevated unrest at Ruapehu had continued during the previous week. Scientists observed upwelling in the lake over the N vent area and visible sulfur slicks on the lake’s surface during an observation flight. The lake water temperature had stabilized at 37 degrees Celsius and continued to be medium gray in color. The lake observations were within normal ranges for a typical heating cycle. Tremor levels remain elevated, though, representing the longest period of tremor recorded over the previous 20 years.

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