Tectonic earthquake detected near Mount St. Helens.

Release Date:

There is no sign that this is connected to volcanic activity.

A Magnitude 3.9 earthquake occurred at 12:36 a.m. on January 3, 2018, about 12 km (7.5 mi) NE of Mount St. Helens at a depth of 10 km (6 mi). The earthquake is a tectonic earthquake aligned with regional stress and faulting in the area. There is no sign that this is connected to volcanic activity.

The M 3.9 was followed by a fairly vigorous earthquake aftershock sequence, with at least 15 events located by the Pacific Northwest Seismic Network. Aftershocks tailed off significantly within several hours.

Follow the link to view Mount St. Helens monitoring data online.