Japan hit by 7.1 aftershock; no nuclear damage seen

TOKYO: A magnitude-7.1 aftershock, one of the strongest since the devastating earthquake of March 11, struck Japan on Thursday 215 miles (345 kilometers) northeast of Tokyo, resulting in warnings of a possible tsunami.

The quake was measured at a depth of about 25 miles and struck about 11.32 p.m. local time near the site of last month's quake, the largest on record in Japan, the US Geological Survey reported on its website. Japan issued a tsunami alert for a possible two-meter wave. A tsunami wasn't expected to reach Hawaii, according to the Pacific Tsunami Warning Center.

"What occurred today is an aftershock in the same area and rupture zone to the magnitude-9 main shock that occurred about a month ago," said Don Blakeman, a geophysicist in the US National Earthquake Information Center in Golden, Colorado. "It is tremendously smaller than the main shock. The main shock caused about 80 times more ground movement."

Tokyo Electric Power Co told reporters that the quake caused no new disruption at the Fukushima Dai-Ichi and Dai-Ni nuclear power units. The Fukushima units were crippled by a 9.0 quake and tsunami on March 11 that left more than 27,000 people dead or missing and caused an estimated 25 trillion yen ($295 billion) in damage.

Power Failures Reported

Thursday's quake, initially estimated at a magnitude of 7.4, caused power failures in Sendai, Yamagata and Fukushima City, according to broadcaster NHK. Miyagi Prefecture reported no immediate damage from the quake, which caused the region to close highways, Kyodo said. Bullet trains were also idled.

Two of three external power lines were knocked out to the Onagawa nuclear plant, north of Fukushima, said Japan's Nuclear Industrial Safety Agency. The Onagawa plant shut safely during the March 11 quake. Tohoku Electric Power Co.'s Higashidori nuclear plant lost a power source and is continuing the cooling process for spent fuel with an emergency generator, the Kyodo news service reported.