By Suzanne Roig and Jorene Barut
HONOLULU (Reuters) - Hawaii ordered evacuations of its coastal areas and braced for a possible tidal wave set off by Friday's earthquake in Japan as a tsunami warning was extended to most of the Pacific basin, including northern California and Oregon.
Some 3,800 miles from Japan, the main airports on at least three of the major Hawaiian islands -- Maui, Kauai and the Big Island of Hawaii -- were shut down as a precaution, and the U.S. Navy ordered all warships in Pearl Harbor to remain in port to support rescue missions as needed.
Civil defense officials ordered all Hawaiian coastal areas evacuated by 2 a.m. local time, about an hour before the first wave was expected to hit the islands at 8 a.m. EST/1300 GMT.
Authorities also ordered evacuations from low-lying areas on the U.S. island territory of Guam in the western Pacific, where residents there were urged to move at least 50 feet above sea level and 100 feet inland.
Guam initially appeared to have emerged unscathed.
"So far no waves," Lorilee Crisostomo told Reuters by telephone from Guam, roughly an hour after the tsunami was first due. Two hours later, Guam Police Department Officer A.J. Alajadia said there was still no sign of trouble.
The Pacific Tsunami Warning Center reported a tsunami more than 5 feet above sea level on the Midway Atoll between Japan and Hawaii, but there were no reports of damage.
The agency 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 U.S. West Coast from Point Conception, California, north through Oregon.
President Barack Obama, a native of Hawaii, was notified of the massive Japanese quake at 4 a.m./0900 GMT and instructed the Federal Emergency Management Agency to be prepared to affected U.S. states and territories, the White House said.
"We will continue to closely monitor tsunamis around Japan and the Pacific going forward, and we are asking all our citizens in the affected region to listen to their state and local officials," Obama said in a statement.
The quake off Japan's northeast coast was the biggest in 140 years and triggered tsunami waves of up to 30 feet that swept across farmland, carrying away homes, crops, vehicles and triggering fires.
On Easter Island, a Chilean territory in the South Pacific, authorities planned to move residents to higher ground hours before a possible tsunami was expected to reach the volcanic isle on Friday afternoon.
Chilean President Sebastian Pinera, whose country was hit by a devastating 8.8 magnitude quake and ensuing tsunamis that killed more than 500 people a year ago, called on Chileans to remain alert, but to continue with their daily routines.
GAS LINES, ALARMED TOURISTS
The Hawaii evacuation zone included the famous Waikiki Beach, the main hotel and tourist hub in Honolulu on the island of Oahu.
Civil defense sirens blared statewide starting shortly before 10 p.m. local time, and police with bullhorns urged residents near shore to higher ground. Authorities also walked the beaches to awaken homeless people.
Lines for gasoline stretched for blocks, and people rushed to stores to stock up on emergency supplies and water. Downtown Honolulu and Waikiki were packed with motorists trying to leave for higher ground and for shelters set up by the state.
As Hawaiians braced for a tsunami, government geologists reported that a 4.6 magnitude earthquake was unleashed at about 11 p.m. by the restive Kilauea Volcano on the Big Island, which has been spewing lava and triggering small seismic tremors since it rumbled back to life last Saturday.
The island of Kauai was expected to be the first hit in Hawaii because the tsunami would take up to 30 minutes to cross the state, said Chip McCreary, a spokesman for the Pacific Tsunami Warning Center.
(Additional reporting by Peter Henderson in San Francisco and Simon Gardner in Santiago; writing by Steve Gorman; editing by Anthony Boadle and Doina Chiacu)