Tsunami from huge quake off Russia could raise sea level by a foot overnight on San Diego County coast

A magnitude-8.7 earthquake off Russia produced a tsunami that could briefly and modestly raise sea levels along the San Diego County coastline starting around 1:15 a.m. Wednesday, according to the Pacific Tsunami Warning Center in Hawaii.

The center has issued a tsunami advisory for the entire West Coast, which means that it has confirmed the creation of a tsunami.

“I think the rise in sea level would be one foot or less,” said Tom Rockwell, a San Diego State University seismologist who has been studying such systems for more than 40 years. “It appears that the quake ruptured the sea floor. But the seawater rise here wouldn’t be as big as it was when a 9.2 earthquake in Alaska produced a tsunami on the West Coast.”

That Alaskan quake on March 27, 1964, briefly raised sea levels by 6 1/2 feet along parts of the San Diego County coast, damaging boats in many areas. It also damaged beach front property, especially in Pacific Beach.

The new 8.7 quake off Kamchatka, Russia, west of the Aleutian Islands, originated 46 miles beneath the sea floor. Many quakes that deep don’t cause big waves at the surface. But the Pacific Tsunami Warning Center registered the tsunami, leading to the advisory. The quake occurred at 4:25 p.m. Pacific time Tuesday.

The center said Tuesday evening that the elevated waves hitting the West Coast could be strong enough, in some areas, to damage docks, especially in harbors.

“This is definitely a mega-thrust quake that occurred on a subduction zone, where one tectonic plate was moving down and under another,” Rockwell said. “This is the zone that’s producing damaging tsunamis in Japan.”