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Massive Earthquake Rocks Japan, Devastating Tsunami Follows

March 12, 2011

USGS Earthquake map

March 11, 2011 Sendai earthquake and aftershocks. Click to go to the real time map

News reports coming out of Japan are bleak after a massive 8.9 earthquake hit the country at 2:46pm local time on Friday, March 11, 2011.  The epicenter of the earthquake was offshore, about 80 miles (130km) east of the city of Sendai and 231 mi (373km) northeast of Tokyo.  The earthquake was followed by a devastating tsunami which rushed inland in the Fukushima prefecture, causing almost more damage than the earthquake itself in some parts of the country.  For scary footage of the tsunami washing ashore and smart commentary from a scientist at the Pacific Tsunami Early Warning Center, see this report from the BBC.

The earthquake occurred in what the US Geological Survey (USGS) calls the Japan Trench subduction zone, where the North American plate and the Pacific plate meet and the Pacific plate moves west, slipping under the North American and Eurasian plates near Japan.  Having trouble wrapping your head around that geography?  Click here for the USGS map of the world’s tectonic plates.  You’ll see that the North American plate wraps over the top of the Pacific plate, underlying not only North America all the way up through Alaska, but also the Bering Straight and a significant part of Eastern Russia.  Japan sits partially over a small finger of the North American plate and partially over the Eurasian Plate, near the boundaries of those plates and the Pacific and Philippine plates.  As you can imagine, that makes Japan particularly earthquake-prone, and the Japanese well aware of the dangers of earthquakes.

Even so, this earthquake was massive.  It is the largest earthquake to hit Japan in recorded history, and one of the largest ever recorded on earth.  Reports are now that at least a thousand people have been killed, possibly as many as ten thousand.  Thousands more are injured or still missing, particularly in areas hit by the tsunami.  Economically it is unclear what this means for Japan, a country hit hard by the world economic crisis.  A re-building boom could spur recovery in some parts of the economy, but with damages expected to reach the tens to hundreds of millions of dollars, it may take an international effort to rebuild the country.

From → Planet Earth

  1. April permalink

    Yay for Spherical trigonometry making plate boundaries confusing.
    I feel at this point a need to petition the Earth on Japan’t behalf to lay off. I had 24 earthquake notifications today over 4.7. One was a 4.9 in the Gulf of California. The rest were off the coast of Japan and ranged in magnitude from 4.7 to 6.6!
    That area of the world needs to be given a break. Unfortunately all this activity means that in a couple months they’re probably going to have a volcanic event. Hopefully not a big one.

    • Yeah, between the earthquakes, the tsunami and the nuclear reactor crisis, the last thing Japan needs is another disaster. They are at sort of in a perfect storm area for earthquakes though, being near the boundaries of four tectonic plates. Apparently little earthquakes happen almost daily there.

      The best thing that can come out of Japan’s “big one” is that California and other earthquake zones learn something about earthquake and tsunami preparedness and how to handle the aftermath of a massive earthquake.

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