An Experimental Study of Tsunami Amplification by a Coastal Cliff

TitleAn Experimental Study of Tsunami Amplification by a Coastal Cliff
Publication TypeJournal Article
Year of Publication2016
AuthorsSim SY, Huang Z
JournalJournal of Coastal Research
Date Published05/2016

There is a general lack of understanding of the effects of coastal cliffs or other complex topography features on tsunami run-ups and tsunami heights onshore. We experimentally investigated several factors that might influence the amplification of onshore tsunami heights in the presence-of a coastal cliff through a set of wave flume tests. The cross shore bed profile used in the experiment was modeled using a composite slope made of three sections, with the gentlest section onshore to replicate the beach. A structure with an adjustable foreslope was mounted onto the beach section to model a coastal cliff. From our experimental results, a critical angle of about 45 degrees was identified: the amplification factor increased with the cliff slope for cliffs gentler than 45 degrees, and cliffs steeper than 45 degrees gave more or less constant amplification factors for a given wave condition. The largest amplification factor found in this study is about 2.8; if water splashing was considered, the amplification factor would be even larger.