Forty years ago Monday, Mount Saint Helens erupted in western Washington, commencing the most destructive eruption in U.S. history.
Fifty-seven people died from the eruption, including a noted United States Geologic Survey (USGS) scientist. The USGS refers to the event as the “worst volcanic disaster in the recorded history of the conterminous United States”.
For approximately two months, a series of earthquakes gradually weakened the volcano’s northern flank, until it finally collapsed on May 18th, 1980. On that morning, a 5.1 magnitude earthquake just below the north side of the volcano triggered a huge high-speed landslide that led to the majority of the destruction.
The slide unleashed magma that exploded with about 500 times the force of the Hiroshima atomic bomb, according to The Los Angeles Times.
A nine-hour-long ash cloud hovered over the Northwest most of that day, traveling “hundreds” of miles away. Here’s what the eruption-induced crater looked like in 2007 (photo credit: Jon Major, USGS):
Because this was the first major volcanic explosion in the United States, however, USGS scientists credit it with helping prompt key studies and research. It was the “ideal laboratory to study volcanic activity”, according to the USGS.
“But the truth is the eruption of Mount St. Helens sparked the advances in cutting-edge volcano science and monitoring that exist today,” the USGS summarized in its 40-year look-back on the eruption last week. “The eruption also led to a new era of volcanic monitoring. During studies at Mount St. Helens, scientists refined their interpretations of monitoring data in order to better forecast future eruptions.”
For more on the Mount Saint Helens eruption, the USGS has more detailed information here.
Featured photo courtesy: Robert Kimmel, USGS