There has been a spike in seismic activity under Mount St. Helens.
There were around 400 earthquakes since mid-July, according the United States Geological Survey. But most were small and not of concern.
Mount St. Helens has had a slight uptick in earthquakes, have you noticed? Most are small (less than M1.0) & not felt at the surface. No cause for concern right now - no significant changes in ground deformation or gases. Volcano remains at normal (green) background levels. pic.twitter.com/Cvor7ow61X
— USGS Volcanoes🌋 (@USGSVolcanoes) October 30, 2023
According to seismologists, it’s because of magma flowing through cracks deep underground.
Scientists observed 40 to 50 earthquakes a week between August and September.
To compare, the mountain averaged around 11 quakes a month since it stopped erupting in 2008.
Comparison shows EQs density during non-eruptive periods (1987-2004) plotted as heatmap (colors). Areas with lots of EQs are blue. EQs from current episode are orange circles. Check out graphic at bottom for depths. pic.twitter.com/ULu1W7JPPm
— USGS Volcanoes🌋 (@USGSVolcanoes) October 30, 2023
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