Forecast Evolution in Tohoku, Japan Following M7.3 on 12/7/2012

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Here we show the changes in earthquake probabilities following friday's M7.3 earthquake off the coast of Tohoku, Japan.  As reported earlier, a 1 meter tsunami was observed on the coast near Arahama, Japan. In this update, we show both the updated timeseries of probability, and the changes in spatial contours of probability.  We adopt the same conditions for the spatial and temporal probabilities as shown in previous blogs, to facilitate comparisons.

The first plot below shows the updated timeseries.  The vertical axis lists the chance of a M>7.25 earthquake within 4 years in the Japan region.  The cross "X" indicates the probability today (12/9/2012), about 16.2%, down from about 82% prior to friday.

The images below represent the spatial probability contours for friday, 12/7/2012 compared to today, 12/9/2012, for M>6.5 earthquakes within 1 year and within 50 km.  Red boxes indicate areas where major changes are visible.  As can be seen, the yellow and other contours are less intense, indicating that probability has decreased in that area.  In addition, the extent of the blue contours is clearly diminished, also indicating a decrease in probability following the earthquake, as expected.

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