Giant 7.8-magnitude quake triggers tsunami alerts across Pacific, threatening US coasts
NOAA issues advisories for Alaska and Hawaii as authorities warn of potential waves after quake near Kamchatka
An offshore magnitude-7.8 earthquake near Russia's east coast triggered tsunami alerts across the Pacific, including Alaska and Hawaii. The quake struck the Petropavlovsk-Kamchatsky region, off Russia's eastern coast, at 2:58 p.m. ET Thursday, prompting the National Oceanic and Atmospheric Administration's tsunami warning system to issue an alert for Hawaii and to place parts of Alaska under a tsunami watch.
In Hawaii, authorities warned that waves of about one to three feet could arrive, and NOAA characterized the situation as advisory rather than a full warning. An advisory-level alert means minor waves or strong currents are possible, but widespread coastal flooding is unlikely.
In Russia, officials warned that the Kamchatka coast could see three to ten-foot waves, raising the risk of coastal flooding in low-lying areas near the peninsula. The Kamchatka Peninsula has experienced several large earthquakes this summer, including a magnitude-7.4 quake on Sept. 13 and a magnitude-8.8 quake on July 29. The quake is being treated as a giant aftershock of that July event by researchers and authorities.
Two tsunami watches were issued for Alaska's Aleutian Islands, covering a swath from Attu to the Amchitka Pass, about 125 miles west of Adak. In the United States, the USGS described Thursday's 7.8 quake as a giant aftershock of the magnitude-8.8 event that struck July 29.
Officials also noted that millions were under tsunami advisories during the earlier July quake, including residents in Japan, Hawaii, and the U.S. West Coast, underscoring the Pacific region's vulnerability to large sea-level disturbances. Authorities urged residents and travelers along the affected coastlines to monitor updates from NOAA, to avoid beaches, harbors and low-lying areas, and to follow local authorities' instructions as the situation evolves.
Geologists say the North Pacific region remains seismically active, particularly around the Kamchatka area, where a string of large shocks has compounded the risk of additional tsunamis. Agencies will continue to monitor sea level changes and weather conditions, issuing updates as new data comes in.