In the area of Castle Rock, Washington State (USA), an earthquake with a magnitude of 3.8 was recorded on September 5, 2026. According to the U.S. Geological Survey (USGS), the epicenter was located approximately 20 km east of the city, at coordinates 46.247° north latitude and 122.642° west longitude. The depth of the focus was approximately 17.67 km (10.98 miles). According to ShakeMap data, the maximum estimated intensity of the shaking was IV on the Mercalli scale, which corresponds to moderate tremors felt by most people indoors. Data from the Did You Feel It? (DYFI) service, which collects eyewitness reports, also recorded an intensity of IV—over 1,025 people reported experiencing the ground tremors. The earthquake occurred in the seismically active Pacific Northwest region of the USA, where seismic activity regularly occurs due to the interaction of tectonic plates. No reports of casualties or significant damage have been received at this time. The U.S. Geological Survey continues to monitor possible aftershocks in the area.