Dam Break Wave over Conical Island

A "full stroke" wave (wave generated by a full stroke of the wavemaker) passing over a conical island. This is intended to represent the passage of a landfalling tsunami around a small offshore island, with the goal of determining the runup characteristics on the beach. Experiment performed in the Directional Wave Basin at the O.H. Hinsdale Lab at Oregon State University, July 2016. This experiment was part of work supported by NSF-CMMI Grant 153890.

(Explanation cribbed from a reply I gave in the comments): One of the purposes of this experiment is to see whether the local belief that offshore islands reduce the inundation of the tsunami on the beach right behind the island was correct or not. That belief can affect the effectiveness of early warning systems. If you watch as the beach gets inundated when the tsunami hits it, the runup of the water is noticeably higher in one spot than elsewhere. That spot is directly behind the island.

The remainder of our experiments show that, at best, the inundation behind the island is no different than it would be on other parts of the beach where there is no island. It is never lower, and in some cases as high as twice the excursion of the runup with no island involved. This fits with field observations taken in Indonesia after a tsunami caused by the Mentawai earthquake in 2010.

Видео Dam Break Wave over Conical Island канала James Kaihatu