Powerful Japanese earthquake sparked Tsunami warnings

A powerful 8.1 magnitude earthquake shook northern Japan yesterday but thankfully there were no reports of tsunami but only small waves in Japan. Thousands were evacuated. From Christian Science Monitor:

The emergency began after a magnitude-8.1 earthquake struck in the Kuril Islands some 110 miles northeast of Hokkaido. The area where the earthquake occurred has seen temblors over a magnitude of 8.0 occurring in 1994 and 2003...

Still, 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 JMA 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.

Countries like Russia, Alaska, Hawaii were given Tsunami warnings while Philippines, Taiwan, Indonesia and several Pacific islands were on Tsunami watch. Hawaii did encounter small tsunami with waves of several meters high, 6 hours after the earthquake struck. From MSN:

The Pacific Tsunami Warning Centre cancelled a tsunami watch initially issued for Hawaii when it became clear the waves would not be large enough to inflict serious damage.

But local civil defence authorities still warned people to stay out of the water and to exercise caution near harbours 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.

On Kauai, a swell of almost one metre flooded a parking lot at Nawiliwili Harbour.