Mount St. Helens is most infamous for her 1980 eruption, which caused a incredible level of devastation, and very recently, hikers have noticed something going on.
Anyone hiking near Mount St. Helens today may have felt a swarm of minor earthquakes that have recently rumbled the area.
The largest of the quakes hit Tuesday night, a magnitude 3.9 tremor that was felt from as far north as Tacoma and as far south as Portland. It is the second largest earthquake to hit the area since 1981.
Swarms of quakes around the Mount St. Helens are relatively common and do not always suggest a sign of impending eruption. Still, there have been a few instances in recent memory that have led the uptick in seismic activity to cause alarm.
Presently, there seems to be no immediate danger of an eruption, according to geologist Trevor Nace, but scientists are continuing to monitor the situation. “While we can’t be certain,” Nace wrote in Forbes, “chances are the next time Mount St. Helen erupts, we will be significantly better prepared.”
The on Sunday, May 18, 1980 eruption was preceded by a two-month series of earthquakes and steam-venting episodes, caused by an injection of magma at shallow depth below the volcano that created a large bulge and a fracture system on the mountain’s north slope.
An earthquake at 8:32:17 a.m. PDT caused the entire weakened north face to slide away, creating the largest landslide ever recorded. This allowed the partly molten, high-pressure gas- and steam-rich rock in the volcano to suddenly explode northwards toward Spirit Lake in a hot mix of lava and pulverized older rock, overtaking the avalanching face.
Approximately 57 people were killed directly, including innkeeper Harry R. Truman, photographers Reid Blackburn and Robert Landsburg, and geologist David A. Johnston. Hundreds of square miles were reduced to wasteland. It caused over a billion U.S. dollars in damage ($3.03 billion in 2017 dollars). Thousands of animals were killed. Mount St. Helens was left with a crater on its north side.