(NewsReady.com) – Mount St. Helens in Washington erupted in 1980 and is known as the most disastrous volcanic eruption in American history. It killed 57 people and left over $1 billion in property damage. There’s been a significant amount of seismic activity at the volcano again.
On June 18, the US Geological Survey (USGS) reported that there have been roughly 350 earthquakes at Mt. St. Helens since February. The seismic events have been relatively small, with 95% of them measuring at a magnitude of less than 1.0.
The earthquakes have been so small that people can’t feel them on the surface, but things have escalated. On May 31, there was a magnitude 2.0 earthquake. Then, in early June, the number of quakes shot up, reaching 38 in one week. They are taking place about four miles below the crater floor.
According to the USGS, the activity at Mt. St. Helens isn’t unusual. The small, short-term increases are considered part of the volcano’s seismic activity. Geologists believe the earthquakes are “associated with pressurization of the magma transport system.” It can happen when new magma arrives, a process known as recharge, which causes stress and leads to earthquakes. It’s not expected to cause any significant events in the near future.
The organization explained that activity can occur over many years before an eruption occurs. For example, the 1980 eruption happened after two months of earthquakes and steam-venting episodes. It caused an 80,000-foot column to shoot into the atmosphere, and 11 states saw ash from the event. From 2004 to 2008, there was also volcanic activity. It was documented as a continuous eruption but never rose over the rim of the crater that the 1980 eruption created.
There were also seismic events from 1988 to 1992, 1995 to 1996, and 1997 to 1999. None of those periods of activity led to eruptions. The USGS also reported that the recent activity is similar to what experts observed from July to December 2023.
While there’s no indication of an eruption in the near future, the USGS will continue monitoring as it has historically done.
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