Pacific tremour prompts tsunami warning in Alaska, British Columbia

A major earthquake measuring 7.5 on the Richter scale stuck the Pacific Ocean off the coast of Alaska in the US this morning, prompting authorities to issue a tsunami warning.

The quake had its epicenter 100 km (60 miles) southwest of Port Alexander in southern Alaska, at a depth of about 10km at 0858 GMT, according to the US Geological Survey, which later downgraded the magnitude from 7.7 to 7.5

The tsunami warning, issued for coastal areas of southeast Alaska and the Canadian province of British Columbia, was later extended to include coastal areas from Cape Fairweather in Alaska to the northern tip of Vancouver Island in Canada.

The West Coast and Alaska Tsunami Warning Center in Palmer, Alaska had warned that tsunami waves could hit first in Langara, in British Columbia province, and reach farther north and west, possibly reaching as far as Homer on Alaska's Kenai Peninsula, in the morning.

The centre, which warned of widespread inundation of land and flooding in the coastal areas, however, withdrew the warning later, saying that some changes in sea level were seen in some areas.

"A tsunami was generated during this event but no longer poses a threat," the center said.

There has been no damage from the earthquake even as the tsunami warning was in effect for at least four hours after the earthquake struck.