In 1980 Mt. St. Helens in Washington State erupted in what is thought to be the most disastrous volcanic eruption in U.S. history.
The 1980 eruption cost 57 lives and caused several billion dollars of damage to areas around the Cascade peak.
Since that major eruption, there have been several less violent episodes at the mountain with the most recent occurring in 2008.
Now, ABC News is reporting that there is an unusual swarm of earthquakes occurring under the mountain.
But a bit out of the ordinary are several small magnitude earthquake swarms in March to May 2016, November 2016 and April 16 to May 5, 2017. During the April 16 to May 5, 2017, swarm, we detected well over 100 earthquakes, all below a magnitude 1.3.
— Liz Westby – USGS
The mountain is thought to be in the process of “recharging,” which will eventually lead to another violent eruption at some unknown point in the future.