News FocusTsunami Research

Tohoku Inundation Spurs Hunt for Ancient Tsunamis

Science  09 Dec 2011:
Vol. 334, Issue 6061, pp. 1341-1343
DOI: 10.1126/science.334.6061.1341

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Summary

Scientists knew of the massive tsunami that struck in 869, during Japan's Jogan era, but may have underestimated its extent and the power of the earthquake that caused it. Had they fully understood the magnitude of the long-ago disaster—and if their warnings that it could recur had been heeded—the toll of the 11 March tsunami might have been far less. So experts are digging all over the Sendai Plain and elsewhere to compare deposits left in March with evidence of prehistoric events. One big surprise is that sand deposits are not always reliable indicators of a tsunami's inland reach. Many vulnerable communities still base risk assessments on disasters described in local historical records, overlooking the possibility of bigger tsunamis striking in prehistoric times. And many localities, especially those far from the subduction zones that produce major earthquakes, still don't realize they lie in harm's way.