Dhaka, July 30 -- magnitude earthquake struck Russia's Far East on Wednesday, triggering tsunami waves that reached Japan's northern coastline and parts of the Kuril Islands, prompting widespread alerts across the Pacific including Alaska and Hawaii.

The tremor, which occurred at 8:25 a.m. Japan time, was initially recorded at magnitude 8.0 by Japanese and U.S. authorities, but was later upgraded to 8.7. The U.S. Geological Survey reported the quake struck at a depth of 19.3 kilometers (12 miles), about 250 kilometers (160 miles) from Japan's Hokkaido island.

Shortly after the quake, tsunami waves began hitting coastal areas. Japan's Meteorological Agency confirmed that a wave about 30 centimeters (1 foot) high reached Nemuro, on Hokkai...