Severe storm waves can cause downslope mass movements of a sloping seafloor in various magnitudes including massive failure. Permanent displacements, even not reaching a massive failure, can be large enough to be destructive to structures on or in the seafloor. Therefore, in offshore and coastal development, both the magnitude of permanent displacements and possibility of a massive failure must be evaluated for intensive wave loading in order to avoid catastrophic consequences. This research will develop a practical and yet rational analysis-based method to evaluate wave loading in a systematic manner for slightly sloping seafloors. The displacement-based approach will be adopted since it can account for various complexities of wave-induced environments in a failure evaluation and, at the same time, can provide the magnitude of the permanent displacements. The evaluation method will be developed through wave tank model tests, case history studies and analytical studies, and will be coded in a computer program.
