In Hawaii, the first signs of the tsunami began to appear, as waves steadily rose over southern beaches on the island of Oahu. The initial waves in Hawaii appeared to have caused no damage.

The massive 8.9 magnitude quake in Japan triggered tsunami warnings for most of the Pacific basin, including northern California and Oregon.

California Gov. Jerry Brown declared a state of emergency on March 11 in four coastal counties, saying the ocean surge from tsunami waves spawned by the earthquake near Japan is imperiling infrastructure and public safety.

In Hawaii, some 3,800 miles (6,200km) from Japan, the main airports on at least three of the major islands - Maui, Kauai and the Big Island of Hawaii - were shut down as a precaution, and the US Navy ordered all warships in Pearl Harbour to remain in port to support rescue missions as needed.

Authorities also ordered evacuations from low-lying areas on the US island territory of Guam in the western Pacific, but the tsunami warning there was lifted several hours later and roads were reopened.

The Pacific Tsunami Warning Center in Honolulu also said the tsunami warning was posted from Mexico down the Pacific coast of South America. The advisory was later extended to a stretch of the US west coast from Point Conception, California, north through Oregon.

US President Barack Obama said he instructed the Federal Emergency Management Agency to be prepared to help Hawaii and other US regions "that could be affected" by the disaster.

Hawaii had a tsunami scare in February 2010 after an 8.9-magnitude earthquake hit Chile but the warning was cancelled about two hours after the first waves came ashore.