Preliminary Observations of the Fujinuma Dam Failure Following the March 11, 2011 Tohoku Offshore Earthquake, Japan

The authors had the opportunity to visit the site of the Fujinuma Dam failure which breached following the March 11, 2011 Tohoku Offshore Earthquake. Our visits occurred a few weeks after the event. The principal purpose of the visits was to observe and document the failure of the main dam and the upstream slide in the auxiliary dam. The authors were greatly aided by the reports available on the internet at the time of the visits, most notably those by Matsumoto (2011). Since that time, other observations have been made by Chigira et al. (2011), Towhata et al. (2011), and Wartman et al. (2011) that assisted in the preparation of this report. The assistance of our Japanese colleagues was invaluable in providing support and in developing and clarifying the observations and information included in this report. The GEER Team greatly appreciates the assistance and information shared by these colleagues.