Tsunami false alarm showcases alert system

TOKYO — A powerful undersea earthquake prompted tsunami warnings Wednesday for Japan, Russia and Alaska, but the danger passed after a series of tiny waves hit the northern Japanese coast.

Still, the event served as a useful test of Japan's sophisticated early-warning system and of its civil-defense emergency procedures designed to speedily remove people from low-lying coastal areas.

Japan issued a major tsunami alert for the northern coast of Hokkaido and some parts of northern Honshu on Wednesday evening local time, sparking the evacuation of hundreds of thousands of people in some of the most remote and inaccessible parts of the nation.

Several thousand people fled to higher ground on Japan's northernmost island of Hokkaido. The waves, however, did not swell higher than 16 inches and rapidly diminished in size.

A tsunami warning posted for coastal areas of Alaska was later canceled, as were watches for Hawaii and the northern tip of British Columbia and precautionary advisories for the states of Washington, Oregon and California.

Small tsunami, some measuring several feet high, crashed into Hawaii on Wednesday, and ocean surges damaged docks in Crescent City, Calif., about 20 miles south of Oregon's state line.

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.

A 1964 tsunami washed away 11 people in Crescent City — the most ever killed by a tsunami in the continental United States.

The emergency began after a magnitude-8.1 earthquake struck in the Kuril Islands some 110 miles northeast of Hokkaido.

Japan is perhaps the best-prepared country in the world for these events. It boasts an extensive system of more than 300 round-the-clock earthquake sensors distributed in the waters surrounding the island nation that relay real-time information to six regional centers. The system has a reputation for being able to predict within five minutes of a quake's occurrence whether a tsunami will strike.

The Japan Meteorological Agency issued the alert some 14 minutes after the temblor, much slower than is typical for the many minor tsunami warnings that periodically occur in the country. Still, that was enough time for most of the small towns along the bleak Sea of Okhotsk coast to usher people to safety.

The town of Sarufutsu, for example, was able to get its entire population of 2,904 people to higher ground within one hour.

Tsunami escape routes and towers were built along most populated parts of the Hokkaido coast after waves of up to 100 feet tall killed 202 and devastated the town of Okushiri there in 1993. That disaster prompted Japan to improve its early warning system.

The government has since periodically commissioned studies into the probable effects of a major tsunami.

One such study conducted in 2003 — showing that a tsunami resulting from a magnitude-8.6 quake in the Pacific south of Japan could kill up to 8,600 people if evacuations were slow — prompted municipalities to improve escape routes.