Tens of minutes after a major earthquake (Mw = 9, at 2:46 pm) had striken the northeast of Japan (the great Tohoku earthquake), an irrigation dam – completed in 1949 on the Abukuma river (height 18.5 m , length 133 m ) to feed a 1.5 Mm ³ reservoir – failed after a breach occured in the main dam. Residents said they heard a muffled explosion before the flood : 8 people were killed, 5 houses are swept away and several others houses were damaged, as well as roads and bridges. The dam was designed to withstand peak ground accelerations up to 1.5 m / s ², but they have reached 4.4 m / s ² on the day of the disaster.

Field survey showed insufficient strength of the material on the middle and upper part of the embankment due to inadequate compaction during construction in the early 1940s and exacerbated by heterogeneity between the different layers of material placed at different periods of construction (during and after the 2nd World War). In addition, the presence of a layer of material with high organic content indicates a probable default in the ground stripping at the beginning of the work.

In the following days, 400 dams were inspected and some disorders or unusual behaviors were discovered in more than 10 % of them, mostly embankment dams : cracking, increased leakage, settlements. On the very day of the earthquake, 252 dams were inspected but the Abukama dam had not yet been inspected when it failed.

The exceptional duration of the earthquake has led the Japanese authorities to reassess the impact of intense and prolonged cyclic loading on dams.