Quiet can mean locked
Cascadia looks calm - and that is exactly the worry.
Compared with California, the Pacific Northwest feels seismically quiet. But much of the Cascadia megathrust is locked offshore, silently storing strain for a magnitude 9 earthquake. The last one, in 1700, sent a tsunami all the way to Japan.
What is happening at Cascadia Subduction Zone
Off the coast of Oregon, Washington and British Columbia, the Juan de Fuca Plate is sliding under North America. Where the fault is locked, the upper plate is being squeezed and lifted with no small quakes to relieve it.
That silence is not safety - it is strain accumulating. When Cascadia last ruptured in January 1700, it produced an estimated magnitude 9 quake and a tsunami recorded in Japanese records that same night.
The hazard record here
THE RECORD HERE
A magnitude 9.0 earthquake struck here in 1700.
It sent a tsunami across the Pacific that was recorded in Japan.
Live figures from the QuakeMate hazard API - USGS earthquake catalog, NOAA tsunami database and published recurrence estimates. Some fields are blank where there is no record.
Recent earthquakes at Cascadia Subduction Zone
- 1.23 km WNW of Oceanside, Oregon2 weeks ago · 13/07/2026, 20:38:01 · -0 km deep
- 1.412 km WNW of Neskowin, Oregon2 weeks ago · 16/07/2026, 19:35:43 · -0 km deep
- 2.63 km SE of Rose Lodge, Oregon3 weeks ago · 10/07/2026, 20:24:39 · 44 km deep
- 2.5OREGON3 weeks ago · 10/07/2026, 20:24:39 · 44 km deep
- 1.93 km S of Fort Hill, Oregon2 weeks ago · 14/07/2026, 20:12:31 · -0 km deep
- 1.921 km W of Forest Grove, Oregon3 weeks ago · 09/07/2026, 20:02:48 · -1 km deep
94 more earthquakes at Cascadia Subduction Zone
Open the QuakeMate app to see every quake here, sorted and mapped - plus real-time alerts when a new one strikes.
Notable events
1700
A magnitude ~9 rupture sent a tsunami across the Pacific to Japan.
2011
Japan’s Tohoku disaster reset how the Northwest prepares for its own megathrust.
What scientists watch
Researchers map the locked patches with GPS and study "slow slip" events, plus the offshore turbidite record that dates past great quakes.
Staying ahead of it
A great Cascadia quake means long, strong shaking and a fast tsunami - the first seconds of warning are the most valuable.
Get QuakeMate freeGet warned before the next one at Cascadia Subduction Zone.
QuakeMate sends a push the instant the ground moves - plus tsunami and volcano alerts. Free to download.
Cascadia Subduction Zone: common questions
Is the Pacific Northwest overdue for a big earthquake?
Cascadia produces great quakes every few hundred years on average, and the last was in 1700. "Overdue" is not quite right, but the probability over the coming decades is significant, which is why the region is investing in early warning.
Why are there so few earthquakes if the risk is high?
Because the offshore megathrust is largely locked. It stores strain quietly instead of releasing it in small quakes - so the calm record is a sign of loading, not of safety.
Related hazard zones
Earthquake data via the QuakeMate API (USGS, EMSC and regional agencies). Historical notes summarise well-established events; magnitudes and dates follow the published record. Live figures may be revised.