Collaborative Research: RAPID - Post-Disaster Structural Data Collection Following the 11 March 2011 Tohoku, Japan Tsunami

University Of Hawaii, Honolulu

Investigators

Abstract

The tsunami triggered by the 11 March 2011 magnitude 9.0 earthquake off Tohoku, Japan, created widespread structural damage in cities along the Japanese coastline. Careful documentation of flow depth and structural response resulting from this tsunami will provide data that can be used to validate tsunami inundation models and corresponding methodologies for calculating structural response due to the inundation. The primary objective of this Rapid Response Research (RAPID) award is to collect time sensitive impact data in Japan from this March 2011 tsunami that will soon be lost, as buildings and infrastructure in the affected areas are repaired or demolished. The investigation team includes researchers and students from the University of Hawaii and Oregon State University. This study will focus on collecting detailed, localized data in several of the most severely damaged areas of the coastline in the Miyagi and Iwate Prefectures, rather than a general survey of all of the inundation areas, which has been undertaken by other local and international reconnaissance teams. Through this award, the reconnaissance team will collect high resolution, ground based LIDAR data. The LIDAR data will be used to generate virtual models that can be queried for measurements such as flow depths, observed maximum run-up, and scour depths at key sites. These will be complemented with manual measurements and analysis of videos and photographs. The LIDAR data will also provide detailed dimensional data for the structures to be studied. The focus in specific areas of study will provide the data needed for validation of the tsunami inundation model. Furthermore, the structural properties of both damaged structures and undamaged structures will be used to determine hydrostatic, hydrodynamic, and impact forces applied during the tsunami inundation. This field reconnaissance will help resolve several key questions in the tsunami design provisions regarding flow velocities and momentum of tsunami bores and/or wave surges over land and scouring, as well as gain information on overarching questions on risk-based design criteria and the ultimate capabilities of structures to resist a maximum credible tsunami. This team will coordinate reconnaissance activities with the UNESCO-led International Tsunami Survey Team. Such data are important for understanding how to design buildings to resist earthquakes and tsunamis for public safety. Many parts of the United States and other places in the world that face similar hazards will benefit from such discoveries, which will help shape building design codes, which are important for public safety. These new standards, validated by information collected on this project, could also provide data in the near future to assist Japan in the recovery phase of their disaster stricken coastal areas. This project will also enable graduate students to observe sites impacted by tsunamis and learn from this event so that they will be better prepared to lead future generations of engineers in reducing seismic and tsunami risk.