The Blanco Fracture Zone earthquake cluster off the coast of Oregon is a part of a wider active system of faults, underwater volcanoes, and actively expanding ridges that increases the likelihood of a significant earthquake along the Pacific Northwest coast.

https://www.king5.com/article/weather/earthquakes/swarm-of-more-than-50-earthquakes-off-oregons-coast-an-indicator-of-previous-activity/281-e60a9401-93ff-450d-8f11-775b50697507