HONOLULU – One of the strongest earthquakes ever measured struck off the eastern coast of Russia on Tuesday evening, triggering fears of a tsunami across much of the Pacific Ocean basin, including Hawaii, Alaska and the entire U.S. West Coast.

Tsunami Warnings are in effect for Hawaii and parts of Alaska, while the entire U.S. West Coast is under a Tsunami Watch after a monster magnitude 8.7 earthquake struck just east of Petropavlovsk, Russia.

“A tsunami has been generated that could cause damage along coastlines of all islands in the state of Hawaii,” the Pacific Tsunami Warning Center said. “Urgent action could be taken to protect lives and property.”

Initial data from the quake suggest tsunami waves reaching more than 9 feet above the tide level are possible along some coasts of the Northwestern Hawaiian Islands and Russia, according to the PTWC. Waves of 3-9 feet (1-3 meters) are possible along some coasts of Hawaii, Japan, and Guam. 

The first waves would reach Hawaii around 7:17 p.m. Hawaiian Time (1 a.m. ET), the PWTC says.

The threat to the U.S. West Coast is still under evaluation. But the PWTC says any first waves wouldn’t reach the Washington and Oregon coasts until 11:40 p.m. PT (2:40 a.m. ET), around San Francisco around 12:40 a.m. PT Wednesday, and around the Los Angeles coast around 1:05 a.m. PT. Waves are expected to reach Shemya at 4:46 p.m. Alaska Daylight time, and 5:46 p.m. AKDT in Adak.

“For other US and Canadian Pacific coasts in North America, the level of tsunami danger is being evaluated,” the PTWC said. “Further information will be provided in supplementary messages.

According to the USGS, an 8.7 magnitude quake would tie for the 8th-strongest quake on record.