Alaskans were woken up on Tuesday Jan 23, at 12.32 a.m. by a magnitude 7.9 earthquake in the Gulf of Alaska. Shortly after, sirens went off warning of a potential tsunami.
The tsunami warning was not restricted to Alaska. It spread throughout all of British Columbia, from Washington to California, and even Hawaii.
Southern Alaska’s seaside city, Kodiak, went from a quiet night with empty streets to a rush of vehicles evacuating to higher grounds. Local high schools and supermarkets were open for refuge as overnight shelters.
The tsunami was reported 175 miles southeast of the coast of Kodiak with a 15 mile depth.
Although there was widespread concern about areas that could witness potential damage, the tsunami warning was lifted only four hours after its release. San Francisco officials kept caution, however, and advised its residents to stay away from the coastline.
Geophysicist Don Blakemen, with US Geological Survey, explained the phenomenon to The Verge. :
“Earthquakes occur because the Earth’s crust is divided into plates. These plates can move smoothly against each other or become stuck. When they become stuck, they build up strain over time, until one day, the plates unstick, releasing energy that causes an earthquake,” Blakemen said. “Just south of Alaska, the Pacific plate is sliding underneath the North American plate, an area called the subduction zone. That’s why the state is highly seismic.”
The earthquake was reported in the same area as a record-breaking 1964 earthquake. This is an area where the Pacific Ocean is slowly sliding under the North American continent. Although this earthquake took place in the Aleutian Trench, it was a result of a strike-slip fault. Pressure was built up as the Pacific Plate was the only part to move horizontally.
Because the earthquake took place underwater and it was a strike-slip fault, great damage was prevented. There are
due to their highly seismic location.