Shishaldin volcano (Fox Islands, USA) - Smithsonian / USGS Weekly Volcanic Activity Report for 23 October-29 October 2019 (New Activity / Unrest)
Pilot and local observations as well as webcam views all indicated that the incandescence at Shishaldin's summit crater was from low-level Strombolian activity during 21-22 October. Seismicity and infrasound signals were consistent with low-level eruptive activity, and a steam plume was persistent. By 23 October lava had filled the crater and during 23-24 October overflowed the N crater rim.
Wed, 23 Oct 2019, 06:0006:00 AM | BY: VN
A 200-m-long lava flow on the N flank melted snow and caused a lahar which traveled 2.9 km and stopped at about 1,230 m elevation. A smaller lava flows caused a 1-km-long lahar to descend the NE flank. Spatter accumulated around the crater rim and melted snow.
On 25 October AVO noted that trace ash deposits had extended at least 8.5 km SE.
Low-level eruptive activity continued during 26-29 October. Seismicity remained elevated, with periods of high-amplitude tremor. Small explosions were recorded during 27-28 October.
A satellite image from 28 October showed a 850-m-long SWIR anomaly on the NW flank from a lava flow. A central spatter cone was visible. Spatter deposits on the snow at the upper flanks was evident, and tephra deposits extended about 2.5 km N.
The lahar on the NW flank branched extensively at lower elevations and was at least 5 km long. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
From: Global Volcanism Program, 2019. Report on Shishaldin. In: Mayberry, G (ed.), Weekly Volcanic Activity Report 23 October-29 October 2019. Smithsonian Institution and US Geological Survey.
Mon, 21 Oct 2019, 17:45
Thu, 17 Oct 2019, 20:32
Renewed lava effusion has been detected and is contained within the crater. AVO raised the status to ORANGE/WATCH. ... Read all