Volcano World

JMA lowered the Alert Level for Aira Caldera?s Sakurajima volcano to 3 (on a 5-level scale) on 27 July, noting that after the larger eruption on 24 July material had not been ejected more than 2 km from the crater; residents were warned to stay 2 km away from the crater. During 25 July-1 August the seismic network recorded about 11 explosions and 19 eruptive events, producing plumes that rose as high as 2.2 km above the summit and ejected material far as 1.1 km. Crater incandescence was visible nightly. No deformation was detected.

Source: Japan Meteorological Agency (JMA)

On 27 July IMO stated that uplift at Askja began in August 2021 and since then had totaled 35 cm, centered in the W part of Askja lake. The uplift was rapid, compared to similar volcanoes around the world, and likely caused by a magmatic intrusion at an estimated depth of 2 km. Seismicity remained low.

Source: Icelandic Meteorological Office (IMO)

Satellite images of Ioto (Iwo-jima) acquired on 15 July showed a darker area in the water along the SE coast, possibly above or near the 2001 vent, and a plume of discolored water drifting NE. Video taken on or around 25 July showed a white plume rising from the same area. Satellite images during 30-31 July showed small rounded gray zones at the water surface.

Sources: Planet Labs,Sentinel Hub

Icelandic Meteorological Office (IMO) reported that an intense earthquake swarm began around noon on 30 July within the Krsuvk-Trlladyngja volcanic system. The earthquakes were located in an area just NE of lava field in Geldingadalir, along the dike intrusion that preceded the March-September 2021 eruption. The swarm was likely caused by a magmatic intrusion at depths of 5-7 km. Earthquakes were reportedly felt in SW Iceland, in Reykjanesbr, Grindavk, the Capital region, and as far as Borgarnes. Several earthquakes were above M 3; a larger M 4 event was recorded at 1403. IMO raised the Aviation Color Code to Yellow, based on above-background seismic levels. At around 1800 the epicenters shallowed to depths of 2-5 km. By 1527 on 31 July almost 3,000 earthquakes had been detected, with four of the events larger than an M 4. A larger M 5.4 earthquake was detected at 1748. IMO reported at 1749 on 2 August that deformation models indicated magma around 1 km below the surface. The intrusion rate was close to double that recorded prior to the 2021 eruption, though by the reporting time the intrusion and seismicity rates had slowed. IMO noted that a similar pattern of events took place prior to the last eruption and stated that the likelihood of an eruption had increased. An effusive eruption began at 1315 on 3 August in Meradalir, near the border of the previous flow field N of Fagradalsfjall. Webcam video showed lava fountains rising along a 300-m-long fissure. As a result, IMO raised the Aviation Color Code to Orange at 1536. Gas-and-steam plumes rose 500-1,000 m high, but no ash was detected.

Source: Icelandic Meteorological Office (IMO)

JMA reported that the number of volcanic earthquakes with hypocenters near Kuchinoerabujima?s crater began increasing around 1000 on 30 July and remained elevated. The Alert level was raised to 2 (on a scale of 1-5) on 31 July. Around 40 volcanic earthquakes were recorded by 1500 on 1 August. JMA noted that daily emissions of sulfur dioxide gas remained low, with a rate less than 50 tons per day. No deformation was detected.

Source: Japan Meteorological Agency (JMA)

According to PVMBG an eruption at Raung at 1719 on 27 July produced a gray ash plume that rose 1-1.5 km above the summit and drifted W and NW. On 28 July a thermal anomaly in the crater was identified in satellite images and data from the GPS network indicated inflation, likely from an intrusion of magma. Seismicity on 29 July was dominated by continuous tremor. The Alert Level was raised to 2 (on a scale of 1-4) that same day, and the public was warned to stay 3 km away from the crater.

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

KVERT reported that moderate activity at Ebeko was ongoing during 21-28 July. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E) explosions generated ash plumes that rose up to 4 km (13,100 ft) a.s.l. and drifted in multiple directions. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

AVO reported that slow lava effusion at Great Sitkin continued during 26 July-2 August. Weather clouds obscured satellite and webcam views during most of the week, though satellite radar data confirmed ongoing effusion; flows thickened but did not advance. Seismicity was low, and occasional local earthquakes were recorded. Steam emissions were visible in satellite and webcam images during 29-30 July. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

The Icelandic Meteorological Office (IMO) reported that increased seismicity, characterized by several earthquakes with magnitudes over 1, began at Grmsvtn during the afternoon of 2 August and continued through the afternoon of 3 August. The largest event was a M 3.6 detected at 1424. IMO raised the Aviation Color Code to Yellow.

Source: Icelandic Meteorological Office (IMO)

KVERT reported that a thermal anomaly over Karymsky was identified in satellite images during 21-23 and 27-28 July. Ash plumes were identified in satellite images drifting 46 km ESE on 27 July. The Aviation Color Code remained at Orange (the second highest level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)