Thursday, April 07, 2011

Major 7.4 Aftershock Renews Concerns In Japan

A major 7.4 aftershock rocked Japan just minutes ago:

Japan was rattled by a strong aftershock and tsunami warning Thursday night nearly a month after a devastating earthquake and tsunami flattened the northeastern coast.

The Japan meteorological agency issued a tsunami warning for a wave of up to 6 feet (two meters). The warning was issued for a coastal area already torn apart by last month's tsunami, which is believed to have killed some 25,000 people and has sparked an ongoing crisis at a nuclear power plant.

Officials say Thursday's aftershock was a 7.4-magnitude and hit 25 miles (40 kilometers) under the water and off the coast of Miyagi prefecture. The quake that preceded last month's tsunami was a 9.0-magnitude.

Buildings as far away as Tokyo shook for about a minute.
The USGS is actually reporting this as two separate and distinct 7.4 aftershocks spaced about 2 minutes apart:
MAP     7.4      2011/04/07 14:32:42       38.253       141.640     25.6      NEAR THE EAST COAST OF HONSHU, JAPAN
MAP     7.4      2011/04/07 14:32:00       38.200       142.000     40.0      NEAR THE EAST COAST OF HONSHU, JAPAN

The quakes occurred at slightly different depths and locations, and while each, by themselves, could have serious consequences, together they add to the woes facing the Japanese in their ongoing struggle to recover the remains of those killed in the tsunami and to regain control over the four damaged nuclear reactors at Fukushima. Shake maps show moderate intensity for the region most heavily affected by the 9.1 monster quake.

By itself, a quake this size could cause tremendous damage in a country that doesn't have strict or adequate building codes. Thus far, the initial reports indicate that the quake didn't add to Japan's misery - though there are tsunami warnings and alerts. 

No such alert is issued for Hawaii, Alaska or the West Coast though.

Meanwhile, TEPCO has evacuated Fukushima in the wake of the latest quake and potential for tsunami.
Public broadcaster NHK reported a tsunami warning for Miyagi prefecture, saying people in that area should evacuate away from the shore to a safe place.

NHK also reported a tsunami advisory for Iwate prefecture, saying a tsunami is expected to arrive in coastal regions there as well.

The Pacific Tsunami Warning Center said based on all available data, "a destructive Pacific-wide tsunami is not expected and there is not a tsunami threat to Hawaii."

The U.S. Geological Survey said the quake was centered 41 miles (66 kilomemeters) from Sendai -- one of the areas worst hit by last month's 9.0-magnitude quake -- and 73 miles (118 kilometers) from Fukushima, where a crisis has been under way at a nuclear plant since last month's tsunami.

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