RAPID: Reconnaissance of the 11 March 2011 Tohoku, Japan Tsunami

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

The 11 March 2011 magnitude 9.0 earthquake off Tohoku in Japan triggered a transpacific tsunami that had basin-wide impact of varying severity. Both the earthquake and tsunami magnitudes are unprecedented in Japan's long historical records of over 1,000 years. This award supports a reconnaissance survey team to investigate the effects of this tsunami along coastlines in Japan, the Pacific Islands, and the western United States. The team will conduct the reconnaissance with Japanese researchers from Tohoku University in Sendai, the University of Tokyo, and the Port and Airport Research Institute, and coordinate with the UNESCO-organized International Tsunami Survey Team. The 2011 event in Japan presents a unique research opportunity since there are now three historic tsunamis with significant impact on the same Sanriku coastline, which may allow differentiating between tectonic and potentially superimposed landslide tsunami sources. The tsunami sources and magnitudes of historic and geologic events inferred from tsunami deposits such as the 869 event need to be revisited. The tsunami survey team supported on this award will collect high quality inundation measurements that will allow the research community to infer the predictive capability of different tsunami models. Tsunami eyewitness videos will be calibrated in situ to extract time series of flow depth and velocity. The obtained field data will be analyzed closely with the existing laboratory data collected by past experimental projects. The primary project deliverable will be a comprehensive multi-scale, geo-referenced database of tsunami damage and flood zone characteristics combined with numerical model results. Education and outreach lectures and briefings will be given at villages surveyed and to eyewitnesses interviewed. The reconnaissance team will coordinate with the UNESCO-led International Tsunami Survey Team. Tsunami reconnaissance of an estimated 1,000-year event will transform tsunami modeling and mitigation with broad implications beyond engineering. Post-disaster reconnaissance following major natural events has yielded significant new insights into both the characteristics of the events as well as the behavior of landforms and performance of infrastructure subjected to these catastrophic events. Through such research into the Tohoku tsunami, researchers may be able to understand the causes of the significant death toll that resulted from this disaster. The measurements and observations will also provide important information that will be used to influence both evacuation and building procedures for the prevention of loss of life and property damage in Japan and in other areas of the world susceptible to tsunamis, such as the impact of a tsunami generated on the Cascadia subduction zone on communities along the U.S. Pacific Northwest and northern California coastlines.