Tsunami Warning in Alaska Downgraded After a 7.3 Magnitude Earthquake Hits Region

Residents living in coastal communities in southern Alaska were ordered to move to higher ground due to a tsunami threat after a 7.3 magnitude earthquake struck on Wednesday at 12:37 p.m. locl time. Officials quickly downgraded and then canceled the tsunami warning for the region. There were no reports of significant damage. “We have seen other earthquakes in the area that have not generated significant tsunami waves, but we’re treating it seriously and going through our procedures, making sure communities are notified so they can activate their evacuation procedures,” Jeremy Zidek, a spokesperson for Alaska’s emergency management division, said. The quake was felt as far away as Anchorage, almost 600 miles (966 km) to the northeast.

The National Tsunami Warning Center issued a warning for an area stretching from approximately 40 miles (64.4 km) southwest of Homer to Unimak Pass, a distance of roughly 700 miles (1,126 km). The National Weather Service posted on its social media that there was no tsunami threat for other U.S. and Canadian Pacific coasts in North America, including Washington, Oregon and California. Alaska’s southern coast is earthquake-prone, and Wednesday’s was the fifth in roughly the same area since 2020, exceeding magnitude 7, state seismologist Michael West said.

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Scientists are warning that a 1,000-foot-tall “mega tsunami” could potentially destroy parts of the United States if a strong enough earthquake hits a specific active fault line over the next 50 years. Alaska, Hawaii, and parts of the mainland America’s West Coast are at risk if an earthquake erupts along the Cascadia subduction zone, which stretches from Northern Vancouver Island to Cape Mendocino, California.

According to the Geological and Geophysical Surveys, Coastal Alaska faces the most serious tsunami risk in the United States. Historically, tsunamis generated by earthquakes in Alaska have caused damage and loss of life along Alaska coastlines. Alaska is the most seismically active state in the country, has had multiple “great” (Magnitude 8 or larger) historic earthquakes, and has the potential to generate the largest earthquakes in the world. On average, Alaska has had one magnitude 8 or higher earthquake every 13 years.

The largest U.S. earthquake ever recorded and the second largest recorded worldwide occurred in Alaska. The 1964 Prince William Sound earthquake was felt over a large area of Alaska and in parts and British Columbia, Canada. The large area of damage and the 3- to 4-minute duration of the quake were unprecedented. Widespread areas south of the Alaska coastline were raised as much as 18 feet and other regions dropped as much as 6 feet. Portions of the overriding crust moved seaward as much as 50 feet in a matter of minutes. In Valdez Arm, the locally induced tsunami waves were reported to reach a maximum height of 170 feet (52 meters). The earthquake resulted in 15 deaths and approximately $284 million in property damage. The ensuing tsunami that followed caused 124 deaths (106 in Alaska, 13 in California and 5 in Oregon) and $116 million in damage.

A significant amount of effort and resources has been dedicated to predicting and mitigating the risks of tsunamis. Since 1998, the Alaska Earthquake Center has partnered with the Alaska Division of Geological and Geophysical Surveys and the Alaska Division of Homeland Security and Emergency Management to enhance coastal community safety by providing state and local officials with the most accurate information for addressing tsunami hazards in their communities. These agencies offer residents with inundation mapping, maritime response maps, permanent flooding maps, community brochures, and a tsunami hazard mapping tool.

Alaska’s seismic activity poses a significant and ongoing threat to its coastal communities, as evidenced by recent earthquakes, long-term tsunami predictions, and historical disasters, such as the 1964 Prince William Sound earthquake. With its position along active fault lines such as the Cascadia subduction zone, the state faces the highest tsunami risk in the U.S. and regularly experiences powerful quakes capable of triggering devastating waves. Fortunately, decades of scientific research and interagency collaboration have led to meaningful advances in hazard monitoring, public education, and emergency planning. As scientists warn of the potential for future mega tsunamis, continued investment in preparedness will be critical to protecting lives and property across Alaska, the Pacific Coast, and beyond.