A powerful magnitude 8.7 earthquake struck off Russia's far east coast on Tuesday, the US Geological Survey said, triggering a Pacific Ocean tsunami advisory.Hazardous tsunami waves could reach areas along the coasts of Russia and Japan in the next three hours, according to USGS.
The quake's epicentre was initially reported some 85 miles (136 kilometres) east of Petropavlovsk in the country's Kamchatka peninsula, at a depth of 12 miles (19 kilometres), USGS said.
American authorities issued a tsunami advisory for areas that include Alaska.
Japan's weather agency also issued a tsunami advisory of up to one metre (3.3 feet) on its Pacific coasts.
The magnitude of the quake was initially reported at 8.0 and later revised to 8.7.
USGS recommended people in threatened coastal areas stay alert and follow instructions from national and local authorities.
