john's picture

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:

john's picture

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:

wGraves's picture

Everybody Calm Down Please - But Being Prepared Never Hurts

A few points.

1. There won’t be any nuclear ‘explosion’ generated by a chain reaction. Nuclear explosives are based upon fast neutron processes. The reactant will splatter or vaporize long before it can ‘explode.’  I seem to recall that it was Gene Wigner who first pointed this out.

john's picture

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". 

jrholliday's picture

Japanese Radiation Readings


With all the uncertainty and doomsday-scenario talk we've been getting on the news, it's sometimes informative to step back and put things in perspective.

jrholliday's picture

Japan Earthquake: before and after

ABC News and Google have teamed up to show aerial photos taken over Japan.  These photos reveal the scale of devastation across dozens of suburbs and tens of thousands of homes and businesses.

john's picture

Four Cities Forecast: Japan Update (March 13, 2011)

On July 30, this author published a blog on this web site giving the probabilities for major earthquakes having magnitudes M>6.7, within 12 months from July 30, 2010, within 150 miles, and for shallow depths of less than 30 km (most potentially destructive conditions), for each of four cities in Japan: Tokyo, Osaka, Niigata, and Sendai.  At that time it was found that probabilities (chance of an earthquake) were the highest near Tokyo, with the second-highest chance near Sendai.

jrholliday's picture

How to help the victims of the Japan earthquake

A powerful 8.9 earthquake shook Japan at 2:46 pm on Friday, the strongest earthquake ever recorded in its history. It's the fifth-largest earthquake ever recorded.

john's picture

Today's M8.9 Sendai Earthquake

Veiwers everywhere on the planet have once again witnessed the destructive power of mother earth.  As the waves recede, we will surely be witness to loss of hundreds, if not thousands of lives, and damages in excess of $100 billion.  Several things about this event are noteworthy from a risk/hazard perspective.


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