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According to Bath's law, a magnitude 9.0 earthquake shouild be followed by an aftershock of about 8.0  For the first week following the mainshock, there was no evidence of such an event.  However, the magnitude 6.8 aftershock that occurred about ahalf hour after the mainshock has now been upgraded to a 7.9 magnitude quake.  This event occurred about 100 km (60 miles) northwest of Tokyo. 

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Tohoku-Oki Tsunami in Hawaii: A Report from the Field

A neighbor of mine returned this week from a vacation in Maui, Hawaii.  She sent me this description:

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Fukushima Radiation Plume: A Report from the Field

A colleague of mine flew from Los Angeles to Taipei, Taiwan yesterday to attend a scientific meeting.  Normally the flight path used by United airlines takes the aircraft down the eastern coast of Honshu, Japan, on its way to Taipei, or if it stops in Tokyo, to Narita.  On this trip the pilot gave an especially wide berth as the aircraft came abreast of Fukushima, passing within about 200 miles of the island. 

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Japanese Data Site for Tohoku-Oki Earthquake (in English)

This is a site used by a variety of Japanese researchers, and is meant to be a service to the international community. As the site says: "Here are some links and information to the recent earthquake.  Most information is in English and some Japanese websites with figures that can probably be understood"

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Research Data Site for the Tohoku-Oki Earthquake

This is a site maintained by researchers in the US and international communities that may also have material of interest to the casual visitors.  A number of these observations are from satellite observations.

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Four Cities Forecast: Japan Update (March 17, 2011)

Here we update the forecast made for the four cities of Tokyo, Niigata, Osaka and Sendai.  The last update was the day after the M9.0 Great Tohoku earthquake.  Since March 13, the chance of an M6.7 within 12 months of March 17, 2011 and 150 miles of the four cities listed has increased for all cities as shown below.  Sendai is currently at highest risk, with Tokyo also at substantial risk.

In tabular form the data is:

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Tsunami Simulations: Tohoku-Oki Earthquake (March 12, 2011)

These impressive simulations of the Japan earthquake tsunami were made by Dr. Steven Ward from UC Santa Cruz.  Dr Ward uses a variety of methods to produce these simulations. All of these movies show different versions of the same calculation.  The idea is that we can use simulations like these in a predictive sense.  Once we know something about the source, in this case an earthquake, we can then run a calculation to determine where the waves are likely to strike.

In the first movie, waves propagate across the Pacific basin, and run-up heights on the shore are estimated:

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Four Cities Forecast: California Update (March 14, 2011)

Visitors to this site have seen forecasts for the four California cites of Los Angeles, San Diego, San Francisco and Sacramento.  Some visitors have asked:  Has the Japanese M9.0 earthquake increased the seismic hazard in California?  As far as we can determine at this time, the answer is "no". 


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