SAN FRANCISCO/QUITO - Thousands of people fled their homes along the Pacific coast of North and South America on Friday as a tsunami triggered by Japan's massive earthquake reached the region but appeared to spare it from major damage.

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The giant wall of water lost much of its energy as it roared thousands of miles across the Pacific Ocean, but many governments took no chances, ordering large-scale evacuations of coastal areas, ports and refineries.

The West Coast and Alaska Tsunami Warning Center downgraded the situation in California from a tsunami "warning" to an "advisory," said California Emergency Management Agency spokesman Jordan Scott.

"Things seem to be settling down at the moment," he said.

Scott added some areas were still experiencing surge activity and that residents should stay out of places deemed off limits by emergency personnel.

With the tsunami still poised to strike South America's coastline, Chile evacuated thousands from flood-prone areas and Peru took similar measures, also closing beaches. Chile was hit by a magnitude 8.8 quake and ensuing tsunamis a year ago that killed more than 500 people.

The waves are expected to reach mainland Chile around midnight local time (0300 GMT on Saturday). The government also upgraded the tsunami alert for Chile's remote Easter Island. But an hour after the high waves were due to roll in, there was still no sign of them, the island's governor said.

Earlier in the day, waves crashing ashore were larger than normal in California and Mexico, but only the town of Crescent City, near the California border with Oregon, and Santa Cruz south of San Francisco suffered any real damage.

Sirens Blare in Hawaii

In Hawaii, 3,800 miles (6,200 km) 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 Harbor to remain in port to support rescue missions as needed.

Civil defense sirens blared statewide, starting shortly before 10 pm local time, and police with bullhorns urged residents near shore to higher ground.

No injuries or property damage were reported after a series of four tsunami waves hit the Hawaiian island of Oahu, said John Cummings, a spokesman for emergency management in Honolulu. The tsunami warning for Hawaii was later downgraded.

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 help affected US states and territories, the White House said.

Chile Residents Alert

Ecuador took extreme precautions after President Rafael Correa declared a state of emergency across the Andean nation on national television and urged residents to move inland.

The area at risk includes the Galapagos Islands - a popular tourist destination known for its wildlife, including endangered species, that inspired British naturalist Charles Darwin's evolution theory in the 19th century.

Oil firm Petroecuador halted production.

Many ports along Mexico's western coast were closed, including Los Cabos and Salina Cruz in southern Oaxaca, the only oil-exporting terminal on the country's Pacific side.

Mexican officials said high waves had hit the northwestern Pacific coast but there were no reports of damage.

Authorities in Canada's British Columbia advised residents to evacuate marinas, beaches and other low-lying areas, but officials there said the waves were minimal.