Risk assessment of nearshore hazard and vulnerability using the entropy method

Abstract

Taiwan is an island surrounded by sea: The area of land is small. Population increases have increased the demand for land development; however, development in the inland plain has reached saturation. In addition to the opening of coastal defense in recent years, the coastal zone, including shore land and nearshore areas, has become an indispensable space. Development has diversified the use of the coastal zone; however, there is high concern toward the marine areas in any future development of the national land space. This study adopted the operational definition of disaster risk presented by the United Nations Disaster Relief Organization (UNDRO) in 1979. Moreover, we used 200 × 200 m2 digital grids to evaluate the risk level caused by existing levels on the typhoon-prone nearshore areas of Taiwan. The utilization of marine areas is expected to enable our sustainable development. Therefore, the vulnerability indicators we selected were in reference to sustainable development; and included social, economic, and environmental factors; the resilience of the marine economic scale; the assessment of environmentally sensitive areas; marine geology; marine depth; and the offshore distances. The entropy method was adopted in order to establish the vulnerability index rank. This study used the risk matrix to combine the level of hazard with vulnerability. The geographic information system was used to display the risk map on the coastal area. We established a local risk assessment model for hazard and vulnerability in the coastal areas of Taiwan.