Tsunami Surge Forces

The existence of surges, or bores, has frequently been observed at certain locations in connection with tsunamis. On several occasions, these bores have been very destructive. The front part of such a bore on a dry bed is examined in detail and a theory developed. This theoretical description is then used, in conjunction with the waterwedge theory, to predict the forces occurring when such a bore strikes vertical wall. Experimental data is presented which compares favorably with the theoretical results, both for the surge tip shape and the forces produced on impact. Shortcomings, both in the theoretical development and in the completeness of the data, are discussed.