A powerful 7.3 magnitude earthquake hit just off the coast of the Fukushima prefecture in northern Japan on Wednesday evening, leaving two dead and nearly 100 injured, the Associated Press reported, citing the Japanese Fire and Disaster Management Agency.
More than two million households are without power, according to the Tokyo Electric Power Co., or TEPCO. The Japan Meteorological Agency (JMA) issued a brief tsunami advisory, with waves of less than three feet expected. The US National Weather Service reported no expected tsunami for the West Coast, Alaska, Hawaii or Guam.
The main quake, which was estimated to have been centred about 37 miles below the sea floor, was preceded by a lesser-magnitude 6.4 earthquake two minutes earlier. Ordinarily, a 6.4 would be considered a big event, but it was quickly revealed to be a “foreshock”.
Large aftershocks are likely for days, and there's still a very slight chance — perhaps 1 in 20 or so — that the 7.3 might be a foreshock to a larger quake in the next three days.
The Fire and Disaster Management Agency said two people were killed and 94 others were injured, including four seriously, the AP reported.
The main shock took place around 11:36pm local time Wednesday. The JMA maintains an extremely dense network of seismometers; moments after shaking began, the agency issued an Earthquake Early Warning that broadcast to computers, phones and television sets. Such warnings are transmitted at the speed of light, making it possible for an alert to reach distant communities before damaging surface waves crawling along Earth's crust arrive.
Shaking in the high Intensity six range was recorded in Fukushima and parts of Miyagi prefectures, with lower six in central Miyagi and high five across much of Iwate and Yamagata prefectures. Surrounding areas saw lower-five shaking, with levels around a four in the Tokyo metropolitan area.
The JMA warned people to pay close attention to seismic activity and rain because of the increased risk of home collapses and sediment-related disasters.
The agency said that the ground may have loosened and that snow covers may have become unstable after the earthquake, increasing the chances of sediment disasters and avalanches.
TEPCO confirmed that there was a fire alarm at its Fukushima Daiichi plant after the quake, but no fire was located. Electricity was out briefly at pools that store spent fuel from nuclear reactors, the agency announced.
The March 11, 2011, earthquake in Japan registered more than a nine on the moment magnitude scale — meaning it released about 355 times as much energy as Thursday's quake.
The Washington Post