The Japan Earthquake, 11th March 2011

11 03 2011


Tsunami near Sendai, Japan

Tsunami near Sendai, Japan (Image: Kyodo News/AP/PA)

This blog focuses on the details behind the earthquake. I will add more information when it becomes available.

At 1446 local time (0546 GMT), a massive earthquake with a magnitude 8.9, hit the north-east coast of Japan, near Sendai, Honshu. The epicentre was located some 130 km (80 miles) off the coast of Honshu and triggered 10 metre high tsunamis that has devastated the low lying countryside.


Footage from Japanese television have shown wide spread destruction as the tsunami swept through farmland, carrying away vehicles, ships and even buildings. Seismologists say it is one of the largest earthquakes to hit Japan since records began some 140 years ago and was of similar magnitude to the Chilean earthquake of February 27, 2010. To put it into context it is also over 8,000 times the Christchurch earthquake last month (February 22 2010).


Coastal areas of the Philippines, Hawaii and many of the small Pacific islands have been evacuated as tsunami warnings have been triggered over much of the Pacific region, with alerts as far as Russia, Alaska and South America. In the last few hours, New Zealand and Taiwan have both downgraded their tsunami warnings. It is hoped that this is an indication that the wave will not be as damaging as previously feared, although low lying Pacific islands are still thought to be at risk, according to the Red Cross.


As of this blog entry, the death toll stands at 60, with many more missing.

Edit (1658 GMT): 200-300 bodies have been in Sendai, the city closest to the epicentre. The death-toll is still unclear.


A passenger train was missing in Miyagi prefecture, and a ship carrying 100 people was swept away, police told Japanese media, while in Kesennuma city in Miyagi prefecture, a fire is engulfing swathes of coastland, including homes and other buildings. There are also reports that a dam burst in north-eastern Fukushima prefecture, sweeping away homes, Kyodo news agency reports.


Another major issue that arose was from one of Japan’s meaning nuclear power plants. It was reported that the Tokyo Electric Power Company’s Fukushima-Daiichi nuclear power plant was leaking and that the surrounding area was becoming irradiated. This was later denied, but the problem remained. It was later confirmed by Japan’s trade minister that there was a problem with one of the reactor vessels, namely that pressure was still rising. The Tokyo Electric Power Co told Japanese news service Jiji News that they were “taking measures” to resolve the problem. News then came from US Secretary of State Hilary Clinton that the US Air Force was delivering a cargo of liquid coolant to the plant via a local air base. According to New Scientist magazine, the reactor in question was “thought to be a boiling water reactor, so the coolant is likely to be demineralised light water, meaning it is depleted of the hydrogen isotope deuterium.” As a result of this incident the Japanese authorities evacuated over 3000 local residents 3km radius of the Fukushima plant. The situation is still ongoing.


(Image: NOAA)

Japan’s Meteorological Agency and USGS say the earthquake occurred at a depth of 24.4 km and was caused as a result of thrust faulting on or near the subduction zone between the Pacific and North America plate boundary. Due to this displacement a tsunami with an estimated height of 10 metres was created. This map from the US National Oceanographical and Atmospheric Agency shows when the tsunami is expected to hit land across the Pacific.

The University of Southern California’s Tsunami Research Centre also has this map showing the theoretical path of a tsunami, with maximum wave heights. The map is not a forecast for today’s events, but the results of modelling studies the centre has done in the past for a quake of similar location and magnitude. (via New Scientist)

More informations will be added as it becomes available.

Maximum wave amplitude: calculated with the MOST forecasting model via NOAA

Maximum wave amplitude: calculated with the MOST forecasting model via NOAA




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