Portland, OR – A magnitude 4.0 earthquake was recorded off the coast of Oregon early Monday, September 29, according to the U.S. Geological Survey (USGS).
The tremor struck at 1:31 a.m. local time (08:31 UTC) about 10 kilometers below the seafloor. The epicenter was located at 43.331°N, 128.143°W, placing it offshore west of the Oregon coastline.
According to USGS data, the earthquake was reviewed and confirmed as a moderate seismic event. At this time, no damage or injuries have been reported, and only one citizen intensity report has been filed through the “Did You Feel It?” system.
USGS forecasts indicate a very low likelihood of significant aftershocks. The agency estimates just a 1% chance of a magnitude 4.0 or stronger aftershock within the next week. The probability of smaller quakes (magnitude 3.0+) remains around 9%.
Earthquakes of this size are not uncommon along the Cascadia Subduction Zone, where the Juan de Fuca and North American tectonic plates meet. Seismologists continue to monitor the area closely due to its potential for larger seismic activity.
Residents who felt shaking are encouraged to submit a report to USGS to help improve earthquake response and research.
