A magnitude 7.9 earthquake near Kodiak Island triggered wide tsunami warnings across the Pacific coast but produced waves under 21 cm.
Key Facts
- Magnitude
- 7.9 Mw
- Depth
- 25 km (16 mi)
- Distance from Kodiak
- 280 km (170 mi) southeast
- Max wave height recorded
- Under 8.3 inches (21 cm) above tide level
- Tsunami warnings cancelled
- Within 4 hours of the earthquake
By the Numbers
Location
Cause → Event → Consequence
A seismic rupture occurred in the Gulf of Alaska approximately 280 kilometers southeast of Kodiak Island at a depth of 25 kilometers. The event was initially assessed as magnitude 8.2 before the USGS revised it downward to 7.9 on the moment magnitude scale.
On January 23, 2018, at 00:31 AKST, the earthquake struck the Gulf of Alaska and was felt across most of southern Alaska, including Anchorage and Fairbanks, as well as parts of neighboring British Columbia. It prompted tsunami warnings and advisories for Alaska, British Columbia, Washington, Oregon, California, and Hawaii.
Residents in low-lying coastal areas were evacuated to shelters and higher ground. The Pacific Tsunami Warning Center cancelled most alerts within four hours after the anticipated tsunami did not materialize; the highest waves recorded on Kodiak Island measured under 21 centimeters above tide level, and no significant damage or casualties were reported.