Magnitude 8.7 earthquake off Russia triggers tsunami alert for Japan, Alaska

The Herald Scotland

30-07-2025

The earthquake prompted Japan and the U.S. Tsunami Warning Center to issue tsunami warnings. A tsunami alert was also issued for the Pacific islands and the USGS said there was a threat to the Northern Mariana islands of Guam, Rota, Tinian, and Saipan.
The Japan Weather Agency said it expected a tsunami of approximately 3.28 feet to reach large coastal areas starting around 9 p.m. ET. The U.S. Tsunami Warning System issued a warning of "hazardous tsunami waves" within the next three hours along some coasts of Russia and Japan.
Emergency management officials in Hawaii issued a tsunami watch for the state. The agency noted that if tsunami waves were to impact the state, the earliest estimated time of arrival would be 1:17 a.m. ET.
"Based on all available data, a tsunami may have been generated by this earthquake that could be destructive on coastal areas even far from the epicenter," the Hawaii Emergency Management Agency said in a statement. "An investigation is underway to determine whether there is a threat to Hawaii."
What do tsunami alerts mean?
The National Weather Service said tsunami messages are issued by the tsunami warning centers to alert local authorities and the public of a possible tsunami. There are four levels of tsunami alerts, according to the weather service:
Tsunami Warning : "Take Action--Danger! A tsunami that may cause widespread flooding is expected or occurring. Dangerous coastal flooding and powerful currents are possible and may continue for several hours or days after initial arrival."
: "Take Action--Danger! A tsunami that may cause widespread flooding is expected or occurring. Dangerous coastal flooding and powerful currents are possible and may continue for several hours or days after initial arrival." Tsunami Advisory : "Take Action--A tsunami with potential for strong currents or waves dangerous to those in or very near the water is expected or occurring. There may be flooding of beach and harbor areas."
: "Take Action--A tsunami with potential for strong currents or waves dangerous to those in or very near the water is expected or occurring. There may be flooding of beach and harbor areas." Tsunami Watch : "Be Prepared--A distant earthquake has occurred. A tsunami is possible."
: "Be Prepared--A distant earthquake has occurred. A tsunami is possible." Tsunami Information Statement: "Relax--An earthquake has occurred, but there is no threat or it was very far away and the threat has not been determined. In most cases, there is no threat of a destructive tsunami."
Contributing: Reuters