A 4.3 magnitude earthquake hit Mount St. Helens at 10:35 a.m. yesterday on the east side of Spirit Lake.
“This one here was a very short one,” said Mike Moss, director of Hoffstadt Bluffs Visitor Center in Toutle, located approximately 15
directional miles from the Johnston Ridge Observatory.
Moss said the earthquake lasted maybe two seconds, shaking the building and windows, “and it was gone.”
A woman at the front desk of the Mount St. Helens National Volcanic Monument Headquarters in Amway, who wished to remain anonymous, also said the earthquake felt very short, yet sharp.
According to Bill Steele, a spokesman at the seismology lab at the University of Washington, today’s earthquake was about 1,200 times more energetic than the 2.5 magnitude earthquake that occurred in late January. Both were of the crustal variety, not magmatic, which includes volcanic activity.
“It’s the largest one we’ve had in a while,” Steele said.
According to the United States Geological Survey’s website, the last three earthquakes of significance in Washington were a 4.5
magnitude Jan. 30, 2009, in the Seattle-Tacoma area; a 3.6 magnitude June 20, 2003 in Carnation; and a 3.7 magnitude May 30, 2003.
Yesterday’s earthquake occurred at a depth of 3.4 miles. It was followed by micro-earthquakes of 2.5 magnitude at 10:37 a.m. and 2.3
magnitude at 12:21 p.m.
“I think it’s pretty normal for this region,” Steele said.
People from as far south as Beaverton, Ore., and as far north as Bremerton reported feeling the earthquake to USGS.
Steele said this Valentine’s Day earthquake should serve as a reminder to residents and municipalities to be prepared for an
earthquake of 6 magnitude — about 1,200 times more energetic than today’s — because “we know these earthquakes are going to be in our future.”