Earthquake hits eastern Russia

Nature : Perhaps the biggest earthquake ever recorded struck off the coast of Russia on Friday. Although its magnitude was calculated to be 8.3, it caused minimal damage because of its great depthâmdash;some 610 km beneath Earth’s surface. The quake originated at the junction of the Pacific and Eurasian lithospheric plates, beneath the floor of the Sea of Okhotsk. Minor tremors were felt as far away as Moscow and northern Japan. Several smaller quakes struck before the large one, but whether they are related has yet to be determined. Geologists began to rethink their theory of deep earthquakes in 1994 when a 636-km-deep quake struck Bolivia; until then, geologists thought earthquakes could not occur so far down because the rock was too hot to rupture quickly.