Tsunami threat passes after 7.8 Russian quake

A powerful earthquake of magnitude 7.8 off Russia's Kamchatka Peninsula triggered a tsunami warning but the threat has now passed, the US Geological Survey and US Pacific Tsunami Centre said.

"Based on preliminary earthquake parameters...hazardous tsunami waves are possible for coasts located within 300km of the earthquake epicentre," the US Pacific Tsunami Centre wrote in an official message. But it later said that based on all available data the tsunami threat from this earthquake had passed.

The quake struck at 11:34am (12:34am CET) on Tuesday about 200km from the city of Nikolskoye on Bering island off the Kamchatka Peninsula.

The epicentre was west of Attu, the westernmost and largest island in the Near Islands group of Alaska's remote Aleutian Islands.

Tsunami waves, however, were unlikely to reach Kamchatka's eastern coast, some 500 km away. The earthquake was very shallow, only 10 km below the seabed, which would have amplified its effect, but it was far from any mainland and there were no immediate reports of any casualties or damage.

The Kamchatka branch of Russia's emergency situations ministry had warned that waves up to 50 cm high could reach Nikolskoye.

The quake was initially reported as a magnitude 7.7 before being revised down to 7.4 and finally upgraded to 7.8, a major quake normally capable of causing widespread and heavy damage when striking on or near land.

The quake was followed by several aftershocks, including a couple above magnitude 5.