Assessment And Zonation Of Geohazards Risk In China Coastal Zone

The coastal zone is very important for the human socioeconomic development. But the coastal is in the complex gelogy environment of sea-land interaction, the geohzard risk and the its devasting impact are very ennomors. So, in order to show the distributed characteristic and risk level of coastal geohazards, the coastal geohazards assessment and zonation in China are performed in this article. First of all, lots of correlative data in China coatal are collected and anaysized, and geohazards are recognised and the geohazards map in China Coatal zone is mapped. Then the classification system of geohazards and evaluate index system are built for assessment and zonation. The results and conclusions are:(1)New geohazards classification system is put forward.This system is based on the principles of criticality, cause of formation and human effect, which are divided into 3 levels. Above is direct type and potential type, and then divided into 6 sub-types,such as tectonis,gravitation, erosion-cumulus,rock and earth-stratum,sea-air interaction and human activity.(2)The geohazard map of coastal zone in China is mapped for the first time with a sclae 1:500,000. From YaLu estury to BeiLun estury, the map consists of DaLian breadth, TianJin breadth, QingDao breadth, ShangHai breadth, FuZhou Breadth, TaiWan breadth, GuangZhou Breadth and HaiKou breadth. The map records most geohazards in coasal zone, such as coastal erosion, sea incursion, fault, coast slide, shallow gas and buried channel etc. and shows the geohazards distributed characteristic in China coastal zone.(3)The evaluation index sysem of coastal geohazards risk is built for the first time which consists of 6 kinds and 5 levels. The 6 kinds are earth-quake zonation, coastal physiognomy zonation, tectonics, burst, human effect and monomeric kind. Based on the criticality, burst difficulty, harmness and danger to human, the 6 kinds each divided into 5 levels. The system gives attention to practiaclity and science and fulfills to the coastal geohazards risk assessment.(4)The geohazard risk zonation is made in China coastal zone for the first time. According to the zonationa result, the coastal zone in China is divided into 5 levels, that are high risk areas, upper risk areas, middle risk areas, lower risk areas and low risk areas. In the coastal zone of China, there is 1 segment at high risk level which located at the easter part of Taiwan island, and 3 upper risk areas are located at the march with Fujian province and Guangdong province. Another 5 segments are in the low risk level at the north of Hangzhou Bay. Middle and lower risk are mainly level in China coatal zone and scattered at the rest segments in the coastal zone.