On October 30, 2025, a magnitude 5.4 earthquake struck 43 miles southwest of Seward, Alaska, at 9:33 AM AKDT. The tremor, originating at a depth of 14.6 miles (23 kilometers), was felt widely across the Kenai Peninsula and throughout south-central Alaska.
The earthquake was recorded at coordinates 59.6308°N latitude and 150.2328°W longitude. Seismologists have confirmed the details using regional seismic data, indicating a notable event for the region.
The tremor’s intensity was sufficient to be felt in various communities at significant distances from the epicenter, including 46 miles (74 km) east of Homer, 53 miles (85 km) east of Seldovia, and 56 miles (90 km) east of Anchor Point. Other notable distances include 57 miles (92 km) southeast of Clam Gulch, 58 miles (94 km) southeast of Ninilchik, and 61 miles (98 km) southeast of Kasilof. Additionally, the quake was felt 62 miles (100 km) east of English Bay and 110 miles (178 km) south of Anchorage, reaching as far as 149 miles (241 km) northeast of Kodiak.
Alaska’s seismic activity is rooted in complex tectonic interactions primarily driven by the megathrust fault, where the Pacific Plate is subducted beneath the North American Plate. This geological setting is responsible for generating some of the region’s most powerful earthquakes, including the infamous 1964 M9.2 Great Alaska Earthquake.
Seismic activity in Alaska can be divided into three primary zones: the Megathrust Zone, where the most potent earthquakes occur; the Wadati-Benioff Zone, which is responsible for intermediate-depth seismicity in the southern and central portions of the state; and Crustal Seismicity that is associated with various faults, notably within the Cook Inlet basin.
The historical context of the region shows that Southcentral Alaska is susceptible to significant seismic events, evidenced by the 1933 M6.9 earthquake that caused considerable damage in Anchorage. The Castle Mountain Fault has also demonstrated its potential for generating substantial quakes, as seen with the 1984 M5.6 Sutton Earthquake.
This recent seismic event serves as a stark reminder of Alaska’s dynamic geological landscape and the inherent risks tied to living in such an active region. Residents and local authorities continue to remain vigilant in the face of ongoing seismic threats, emphasizing the importance of preparedness and awareness in mitigating risks associated with future earthquakes.