Trident volcano (Alaska) - Smithsonian / USGS Weekly Volcanic Activity Report for 28 September-4 October 2022 (New Activity / Unrest)

AVO raised the Aviation Color Code for Trident to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) on 29 September due to an ongoing seismic swarm. The swarm began on 24 August and within about four days the seismic network began detecting episodes of weak seismic tremor and low frequency earthquakes. The events were initially located at depths around 25 km, but then they progressively shallowed to around 5 km by 28 August.
Earthquakes were located 3-6 km deep since then, though some deeper events were recorded. AVO attributed the swarm to moving magma or magmatic fluids and noted that seismic swarms had previously been recorded with no subsequent eruptions.

Source: US Geological Survey Alaska Volcano Observatory (AVO)
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From: Global Volcanism Program, 2022. Report on Trident. In: Mayberry, G (ed.), Weekly Volcanic Activity Report 21 September-27 September 2022. Smithsonian Institution and US Geological Survey.