Coastal protection measures for tsunami disaster reduction

Abstract

Tsunami may be generated by earthquake triggered movement of the sea bottom, landslides and collapses. It has caused great impacts on human life and coastal environments, including massive loss of human life, devastation of coastal ecosystems and settlements, and damage to infrastructure and facilities. In this chapter, tsunami protection works will be investigated as hard structures likes tsunami breakwaters, sea walls etc. and natural barriers including coastal forest etc. except soft approaches (education, awareness, evacuation, etc.). Although hard structures may provide highly effective protection, they may have high cost and may also cause large amount of negative environmental impact on the coastal areas. That is why, natural coastal barriers which have lower environmental impact and higher additional natural value can be considered as a protection measure against tsunami effects. Tsunami damage occurs mostly in the nearshore zone and in the coastal area behind the coastline because of the tsunami hydrodynamics during the run-up period. Therefore, tsunami run-up height was also investigated. Tsunami run-up heights for impermeable and permeable (not armored and armored) beaches were examined and empirical equations suggested. Following, coastal protective measures, to reduce tsunami damage on coastal areas were analyzed as hard structures and natural barriers. Furthermore, the effects of coastal forests on tsunami run-up heights were discussed and empirical equations suggested.