A powerful earthquake of magnitude 7.8 hit off Russia's Kamchatka Peninsula and triggered a tsunami warning, but the threat soon passed, the U.S. earthquake monitoring agencies said early on July 18.
The quake struck about 200 kilometers from the city of Nikolskoye on Bering Island off the Kamchatka Peninsula. The epicenter was west of Attu, an island in Alaska's Aleutian chain.
The earthquake was very shallow, only 10 kilometers below the seabed, which amplified its effect, but it was far from any inhabited areas and there were no immediate reports of any casualties or damage.
The Kamchatka Emergencies Ministry warned that waves up to 50 centimenters high could reach Nikolskoye. But the tsunami threat quickly passed.
A 7.8 magnitude temblor is a major quake capable of causing widespread and heavy damage when striking on or near land.
The quake was followed by numerous aftershocks, including several above magnitude 5.0.