Review of the Cause of Fujinuma-ike Failure - Summary

Summary of the 1/25/12 report on the cause of the 2011 Fujinuma-ike failure, translated by JCOLD. According to Japanese law, a dam is defined as a water storage structure on a regulated river and at least 15 m high. Fujinuma-ike was on a non-regulated river and treated as an irrigation pond, although it is a dam by ICOLD definition. The panel considers that the primary cause of the failure of Fujinuma Dam is the nature of its upper and middle embankments and the triggering cause is the strong earthquake motion and its long duration.