Mount St. Helens is the only volcano in the Cascade Range that has erupted over the last century.
Does that mean we don’t have to worry about the Cascades as a volcanic hazard anymore? That answer is decidedly “no”
Most of the volcanoes in the Cascade Range show signs of activity – small earthquake swarms, hot and cold springs, fumaroles or the occasional bouts of deformation.
However, only St. Helens has erupted since the 1915 activity at Lassen Peak on May 22, 1915.
This means that although we have thirteen major composite volcanoes plus a multitude of smaller cinder cones and lava domes running from California into Canada, only one has experienced an eruption in the past 100 years. For an entire volcanic arc, that seems quiet.
Seismic activity has recently been reported near Mount St. Helens. Is the area waking up?