The 2011 Tohoku earthquake and dams

Preliminary report of the behavior of dams during the magnitude 9.0 Tohoku earthquake of March 11, 2011. Dam inspections began Immediately after the earthquake; more than 400 dams were inspected by March 31. Generally dams performed well with minor or moderate cracking at embankment dams, but one earthfill irrigation dam failed. Fujinuma-ike ("ike" means pond) was a non-regulated 18.5 meter high earthfill structure completed in 1949. The preliminary investigation suggests that a very long duration of ground motion and a number of subsequent strong aftershocks rendered more effects on embankment dams than on concrete dams. 8 pp.