Volcanos

Roundup of Global Volcanic Activity - New Activity for the week 5 October -11 October 2022

Chirinkotan - Kuril Islands (Russia) : SVERT reported that an ash plume from Chirinkotan was identified in satellite images at 1030 on 7 October rising 3.5-4 km (11,500-13,100 ft) a.s.l. and drifting 80 km ESE.

Grimsvotn - Iceland : Icelandic Meteorological Office (IMO) reported that recent GPS measurements indicated that the ice sheet had subsided about 3 m and the lake beneath the glacier at Grímsvötn had begun to drain, though the water had not reached the glacier’s margins. Neither seismicity nor gas emissions were elevated, though activity at the volcano had been increasing over time. Notably, a pulse of seismic tremor was recorded for about an hour during the previous week, and magmatic gases were measured in fumarolic plumes in 2020. By 12 October the outflow of water was about 300 cubic meters per second, with the onset of the jökulhlaup occurring slower than initially calculated, and the ice sheet had subsided a total of 7 m. The flooding was likely going to be equal to that seen during the summer and would likely not impact bridges or structures.

Mauna Loa - Hawaiian Islands (USA) : On 5 October HVO noted recent increases in seismicity and deformation at Mauna Loa. The number of earthquakes increased from 5-10 per day in June to 10-20 per day during July-August. The number of daily earthquakes again intensified, to 40-50 per day, starting at about 0200 on 23 September, and peaks as high as 100 per day were recorded on 23 and 29 September. The small-magnitude (less than M3) earthquakes occurred beneath Moku‘aweoweo, the summit caldera, at depths of 2-3 km. Inflation accompanied the swarm and had also increased during the past two weeks. Daily earthquake counts were relatively unchanged during 6-12 October. Data from Global Positioning System (GPS) instruments at the summit and flanks showed continuing inflation, though data from tiltmeters at the summit did not show significant surface deformation over the past week. Earthquakes were clustered beneath the summit caldera at depths of 3-5 km and below the NW flank at depths of 6-8 km.

Mayon - Luzon (Philippines) : PHIVOLCS reported that since the Alert Level for Mayon was raised to 1 (on a 0-5 scale) on 21 August monitoring data had showed nothing notable. Changes in morphology of the dome and minor aseismic extrusion estimated at about 40,000 cubic meters was detected during 6 June-20 August based on daily visual and camera monitoring data. Based on these observations, the lava dome grew an additional 48,000 cubic meters by 4 October; re-mobilized light-colored ash had been deposited in Miisi Gully (S flank) beginning 2 October, likely derived from lava fragmentation during the extrusion process. Freshly extruded lava at the base of the summit lava dome was seen during an aerial survey conducted on 7 October. Daily white steam plumes were visible drifting down-flank and then to the W, WSW, and SSW during 8-10 October. Electronic Distance Measuring (EDM), precise leveling, continuous GPS, and electronic tilt monitoring data showed that the volcano had been slightly inflated, especially on the NW and SE flanks, since 2020. Short-term inflation on the W to SW flanks and short-term deflation on the E and SE flanks had been detected since August.

Nishinoshima - Izu Islands : JMA reported that the eruption at Nishinoshima continued during 5-11 October. Ash plumes rose 2.2-3.5 km (7,200-11,500 ft) a.s.l. and drifted in multiple directions.

Stromboli - Aeolian Islands (Italy) : INGV reported that activity at Stromboli had been more intense in the past two weeks with a large explosion on 29 September, short-lived lava overflows of the craters during 3-4 October, and collapses with pyroclastic flows and lava flows on 9 October. At 1524 on 29 September an explosion at vent N2 in Area N (North Crater area) generated an ash plume that rose 300 m above the summit and ejected abundant lava fragments, lapilli, and bombs along the Sciara del Fuoco. Activity during 3-9 October generally consisted of ongoing explosions from three vents in Area N and at least two vents in Area C-S (South-Central Crater area). Low-intensity explosions from the N1 vent (Area N) ejected bombs and lapilli 80-150 m high every 10-20 minutes. Explosions ejecting coarse material, along with sometimes intense spattering, occurred at two N2 vents. Explosions from at least two vents in Area C-S, which were not visible due to the camera views, ejected ash and coarse material less than 150 m above the vent at a rate of 1-6 events per hour. At 1108 on 3 October a fissure opened on the outer flank of N2, within the Sciara del Fuoco, and produced a lava flow that traveled to the coast; the flow was cooling by 1800. At 1107 the next morning, 4 October, lava overflowed the N crater (likely N2) and unconsolidated lava rolled down the upper part of the Sciara del Fuoco. Activity again intensified on 9 October beginning at 0921 when lava overflowed from an area in the N part of N2 and lava effused from the fissure that had opened on 3 October. At 0922 the rim of N2 collapsed and generated a pyroclastic flow that traveled down the Sciara del Fuoco, reached the sea within 30 seconds, and advanced over the water for a few hundred meters. Immediately afterwards a large amount of lava flowed down the Sciara del Fuoco in two main branches and reached the coast within a few minutes. Lava continued to flow to the coast during the rest of the day. The Dipartimento della Protezione Civile raised the Alert Level to Orange (the second highest level on a four-color scale). Collapses of material in the Sciara del Fuoco continued overnight, possibly due to erosion of the channels from lava flows. By 0919 on 10 October lava flows were only reaching part way down the Sciara del Fuoco, stopping about 400 m from the coast. Lava flows continued to stop part way down the flank during 10-12 October. Frequent collapses of material in the channel eroded by the lava flow and material from the lava flow itself descended to the coast. Spattering from Area N was visible.

Taal - Luzon (Philippines) : PHIVOLCS reported continuing unrest at Taal during 5-11 October. Upwelling gasses and hot fluids in the lake continued to be visible. A small, three-minute-long phreatomagmatic burst occurred on 5 October; according to the Washington VAAC an ash plume rose to 600 m (2,000 ft) a.s.l. and drifted SW. White steam emissions rose 900 m above the lake, though during 10-11 October plumes rose as high as 2.4 km.