Small tsunami, some measuring several feet high, crashed into Hawaii on Wednesday, slightly injuring one swimmer, as ocean surges buffered a northern California harbor, damaging docks.

The waves hit Hawaii about six hours after a magnitude 8.1 earthquake struck north of Japan, triggering tsunami warnings as far away as Alaska. No one was evacuated.

Thousands of people living along northern Japan’s Pacific coast fled to higher ground, but Japan’s meteorological agency withdrew its tsunami warning after about three hours. Tsunami warnings for Russia and coastal areas of Alaska also were canceled, as were tsunami watches for Hawaii, the Philippines, Taiwan, Indonesia and several Pacific islands.

Stuart Koyanagi, a geophysicist at the Pacific Tsunami Warning Center, said officials canceled their tsunami watch for Hawaii when it became clear the waves were unlikely to top one meter, or about 3.3 feet.

“Usually things around a meter or less are not going to cause problems. It’s not a big enough wave,” Koyanagi said.

Hawaii civil defense authorities warned people to stay out of the water and to exercise caution near harbors given the possibility the earthquake would generate unusual currents around Hawaii.

A woman swimming at Waikiki suffered cuts when she was sucked through an opening in a seawall as the water receded just before the swells arrived. She was otherwise fine, said John Cummings, a spokesman for Oahu Civil Defense.

On Kauai, a 2 1/2-foot swell flooded a parking lot at Nawiliwili Harbor. It was one of a series of waves that struck the island, said Mark Marshall, Kauai County civil defense administrator.

In California, the National Weather Service reported ocean surges from 1 to 6 feet and waves gusting up to 30 mph but did not call an official tsunami warning or watch. Surges were observed from Port San Luis on the Central California coast to the Oregon border.

In Crescent City, about 20 miles south of Oregon’s state line, two docks were destroyed and another was badly damaged when a five-foot surge, believed to be the result of the undersea earthquake, rolled into the city harbor, causing up to $700,000 in damages.

Harbor workers noticed a fast-moving current around mid-afternoon that harbor master Richard Young described as a “river within the ocean.”

Crescent City is familiar with the power of ocean surges.

A 1964 tsunami washed away 11 people — the only tsunami to take lives in the continental United States.