COASTAL TSUNAMI GEOMORPHOLOGICAL IMPACTS AND SEDIMENTATION PROCESSES: CASE STUDIES OF MODERN AND PREHISTORICAL EVENTS

摘要

The study of coastal flood risk is of considerable interest to engineers, planners and politicians. Tsunami represents one of the most potentially serious forms of coastal flood risk. This paper reviews recent advances in research into geomorphological impacts and sedimentation processes associated with tsunami inundation. Detailed geomorphological and sedimentological investigations made in the cases of the Flores Tsunami generated by 1992 Indonesian earthquake, the 1998 Papa New Guinea tsunami and the Holocene Storegga Tsunami caused by a catastrophic submarine landslide off Storegga, Norway at circa 8,000 yrs B.P. are selected here. Although much is known on occurrence of this type of catastrophic coastal flooding which may cause loss of life, widespread destruction of property, and of infrastructure and industrial installations, it is not widely known, as these case studies show that the extent of flooding and geomorphological impact vary significantly along a coastline. Estimating the impact of tsunami and the vulnerability of coastlines to these phenomena may assist in coastal zone planning and management decisions. This paper also presents a conceptual model of coastal tsunami sedimentation processes deduced from the case studies and outlines diagnostic features of tsunami deposits.