Mount St. Helens "recharging" after USGS records earthquake increase in 2024

PORTLAND, Ore. (KOIN) -- Earthquake activity around Mount St. Helens spiked to nearly 350 quakes between February 1, 2024 to June 18, 2024.

The increase in earthquake activity has only been small magnitude quakes, but an increase nonetheless. The Cascades Volcano Observatory said, "Over the past several months, small magnitude earthquakes have been located at Mount St. Helens. The seismicity is similar to what was observed at this volcano from July to December 2023. No significant changes have been observed in other monitoring parameters and there is no change in alert levels at this time. Mount St. Helens remains at normal, background levels of activity."

In an X (Twitter) post from the USGS Volcanoes, the seismic activity seen recently could mean the arrival of additional magma known as a process called 'recharge'.

"Small magnitude earthquakes located beneath Mount St. Helens at depths well below sea level are generally thought to be associated with pressurization of the magma transport system. One cause for this pressurization is the arrival of additional magma, a process called recharge." The Cascades Volcano Observatory went on to explain that, "magma slowly rises through the lower crust and accumulates in a reservoir about 2.5 to 6 miles (4‒10 km) below sea level. Recharge events can occur when magma enters this upper reservoir and increases stresses that lead to earthquakes."

The USGS Cascades Volcano Observatory says they will continue to monitor this activity and will provide any updates or warnings if warranted.