Probabilistic Forecasting of Water Heights and Life Loss in Japan for the 3/11/2011 Great Tsunami

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The great tsunami disasters in Japan (3/11/2011) and in the Indian Ocean (12/26/2004) reveal limitations in traditional methods of forecasting the probability and recurrence intervals of large infrequent events. For Japan, two measures of tsunami magnitude were studied, water height and life loss, using size-cumulative frequency distributions. For both magnitude measures all data set distributions are well fit by power scaling functions which are the basis of probabilistic forecasts. The historic Japanese data, including the 3/11/2011 tsunami, are from the US National Geophysical Data Center. The data were aggregated for all of Japan, and for five specific locations on the east coast of Honshu Island, the area most affected by the 3/11/2011 event. Tidal gauge water heights at the five locations exhibit power scaling with scaling exponents ranging between 0.9 and 1.6 for water heights ranging between 1.21 and 4.0 meters. Maximum water heights (measured by any method) for all of Japan from 684 to 2003 exhibit power scaling with a scaling exponent of 0.7. The recurrence interval for a maximum tsunami water height of 40 m (reported for the 3/11/2011 tsunami) or greater, at any location along the Japanese coast, is ~264 years. Tsunami life loss for all of Japan from 1905 to 1993 exhibit two power scaling regimes (one for losses less than and one for losses greater than 1223 lives) with scaling exponents of 0.3 and 1.4 respectively. The recurrence interval for Japanese tsunami life loss of 15,550 (reported for the 3/11/2011 event) or greater is ~842 years.


Poster presented at the 2011 Fall Meeting of the American Geophysical Union (AGU), San Francisco, CA.

Poster Presentation Number NG51C-1663.

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