A small flurry of earthquakes occurred beneath Mount St. Helens yesterday (Wednesday, February 21). At 4:51 p.m. local time, a magnitude 2.3 earthquake occurred about 4 km beneath the crater floor. It was followed by 2 smaller earthquakes at 5:00 p.m. and 5:06 p.m. During the next hour, several small, surficial events occurred in the crater. These may have been rockfalls, snow avalanches, or small releases of steam from the dome. No flows occurred outside the crater. Activity returned to normal levels by 6 p.m. local time. |
The U.S. Geological Survey and University of Washington monitor earthquakes and other activity at Mount St. Helens as part of the USGS Volcano Hazards Program. Information updates will be posted here during the first week of each month, or more often if conditions warrant.