Volcano World

On 9 September IMO raised the Aviation Color Code for Askja to Yellow, noting that inflation that began in early August was ongoing and notably rapid. The uplift was centered at the W edge of Oskjuvatn caldera, which rose a total of 7 cm. The data suggested that magma was accumulating at 2-3.5 km depth.

Source: Icelandic Meteorological Office (IMO)

The Japan Coast Guard reported that during a 12 September overflight of Fukutoku-Oka-no-Ba, observers noted that the W island was unchanged while the E side had been completely eroded and submerged. Yellow-green to yellow-brown discolored water extended from the vent area to the SW, S, and SE, suggesting continuing eruptive activity. Another area of discolored water had an approximate diameter of 2 km and was about 2 km ENE of the volcano. The discolored water prompted JMA to issue a navigation warning to nearby vessels.

Source: Japan Coast Guard

Instituto Volcanolgico de Canarias (INVOLCAN) reported that a seismic swarm beneath Cumbre Vieja at the S part of La Palma began at 1618 on 11 September and was likely associated with a magmatic intrusion. The swarm intensified in number of events and magnitude, and by 1600 on 12 September a total of 315 earthquakes had been recorded and ranged 8-13 km in depth. The largest event was a M 2.8 (on the Mb_lg scale). On 13 September a scientific committee comprised of representatives from multiple agencies and institutions raised the Alert Level to Yellow (the second lowest level on a four-color scale) for the municipalities of El Paso, Los Llanos de Aridane, Mazo, and Fuencaliente de la Palma. By 0800 on 14 September 2,935 earthquakes had been detected. Larger events were felt by residents during 13-14 September; the largest earthquake was a M 3.9, recorded at 0600 on 14 September. Overall, the events were becoming shallower (8-10 km) and hypocenters migrated slightly to the W. GPS and tiltmeter networks showed deformation totaling 1.5 cm centered over the clusters of epicenters. INVOLCAN noted that 10 seismic swarms have been detected at La Palma since 2017; one in 2017, one in 2018, five in 2020, and three in 2021. The earthquakes in the previous swarms were deeper, between 20 and 30 km, and were less intense than the current swarm.

Sources: Gobierno de Canarias,Instituto Volcanolgico de Canarias (INVOLCAN)

The U.S. Geological Survey reported that emissions of ash and sulfur dioxide from Pagan were last detected on 6 September, though robust steam plumes occasionally continued to be visible at least through 14 September. The Aviation Color Code and the Volcano Alert Level were lowered to Yellow and Advisory, respectively, on 10 September.

Source: US Geological Survey

On 14 September GeoNet reported that intermittent ash emissions at Whakaari/White Island continued to be visible during the previous week. Vigorous fumarolic plumes from the active vent area sometimes carried minor amounts of ash downwind at low altitudes and occasionally deposited ash on the island. Periods where ash was visible in the emissions did not correspond to explosive seismic or acoustic signals, suggesting that the ash was produced by weak wall fragments falling into the gas stream through the active vents and not from eruptive activity. Seismicity was characterized by low levels of volcanic tremor and occasional volcanic earthquakes. The Volcanic Alert Level remained at 2 and the Aviation Color Code remained at Yellow.

Source: GeoNet

JMA reported that incandescence from Minamidake Crater (at Aira Caldera?s Sakurajima volcano) was visible at night during 6-10 September. Deformation data showed inflation beginning at around 0300 on 13 September. The Alert Level remained at 3 (on a 5-level scale), and residents were warned to stay 2 km away from the crater.

Source: Japan Meteorological Agency (JMA)

SERNAGEOMIN lowered the Alert Level for Cerro Hudson to Green (the lowest level on a four-color scale) on 7 September, based on decreased activity. Neither morphological changes nor thermal anomalies were visible in satellite images or webcam views during 16-31 August. Seismicity remained low and sulfur dioxide emissions were not recorded.

Source: Servicio Nacional de Geologa y Minera (SERNAGEOMIN)

According to volcanologists in Severo-Kurilsk (Paramushir Island), about 7 km E of Ebeko, explosions during 4 and 6-8 September produced ash plumes that rose as high as 2 km (6,600 ft) a.s.l. and drifted N, S, and E. Ash fell in Severo-Kurilsk on 6 and 8 September. The Aviation Color Code remained at Orange (the second highest level on a four-color scale).

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

AVO reported that lava effusion continued at Great Sitkin during 7-14 September, though weather clouds often prevented webcam and satellite views. Seismicity remained elevated and was characterized by small earthquakes consistent with lava effusion. A radar image from 9 September indicated that the lava dome had grown to 1,100 m E to W and 860 m N to S, and was 25-30 m thick. Lava began to advance though a gap in the S rim of the summit crater. Elevated surface temperatures were visible in satellite data on 14 September. The Aviation Color Code and the Volcano Alert Level remained at Orange and Watch, respectively.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Icelandic Meteorological Office (IMO) reported that the jkulhlaup from the eastern and western parts of Grmsvtn's caldera that began on 1 September had decreased during 8-10 September. IMO warned of continuing flood conditions in the downstream parts of the Skaft river.

Source: Icelandic Meteorological Office (IMO)