The Vulnerability Analysis And Evaluation Of The Coastal Geological Environment In The Southern Laizhou Bay

Coastal zone is defined as the junction region with significant land-ocean interactions. From view of natural science, coastal zone is an extremely complex, highly diversified and complex cross-system area, which is in a state of continuous movement and changes. From view of ecology, coastal ecosystems are in a high productivity zone in which materials and energy are intensely exchanged, and is also ecologically fragile zones. From view of geological environment, coastal zone is a vulnerable geological environmental region, due to complex marine force, frequent natural disasters.In this thesis, the geological environment in the southern Laizhou Bay was studied. Methods of image processing, remote sensing image analysis, statistical analysis and the combination of qualitative analysis and quantitative calculation were used to study the vulnerability of geological environment in the southern Laizhou Bay. The study include the pattern of vulnerability, its driving forces of the formation mechanism, the evaluation index system and the evaluation method of vulnerability. In order to reduce the vulnerability some control measures were proposed. The main conclusions are as following:(1) The patterns of the geological environment vulnerability of the southern Laizhou Bay are seawater intrusion, coastal erosion, coastal wetlands degradation. By calculating the statistic datum from 1987 to 2006, some conclusions are obtained as below: From 1980s to 1997, the seawater intrusion was at an accelerated development phase, and the most value was obtained in 1997. After 1998, it entered into the stabilization phase. The changed trend of intrusion scope are from narrow to slightly expanded. The pattern of coastal erosion from 1985 to 2006 was that the shoreline is from retreat to maintain basic stability, The depth curve of the most shores maintain backward trend, which becomes relatively smaller at the end. The trend of the cutting rate of beach face is larger-reduced-slightly larger. The main characteristics of degraded wetlands were the reduction of natural wetlands and beach-wetland area, and large-scale increasing of salt pan wetlands area and aquiculture pond wetlands area.(2) From the factors of the natural and human being activities, the driving forces and formation mechanism of the vulnerability of geological environment were analysed in the southern Laizhou Bay. The main natural factors are climate change, sea level rising, storm surges, landscape fragmentation of wetlands. The human active factors were mainly development of salt pan and aquiculture pond and exploitation of groundwater.(3) According to the pattern and the driving forces of vulnerability, the evaluation index system of vulnerability of coastal geological environment was constructed. Three terms datum were selected as the main study datum such as 1987, 2002 and 2006. The factor weight was determined by relevant analysis and factor analysis, and the most important factors of vulnerability were quantitatively analysed. Using the grey multi-hierarchy evaluation, the different stages of vulnerability degrees in the study area were evaluated. The result showed that the greatest impact factors were human activities and sea level rising. The vulnerability degree in 1987 was heavier vulnerability. The serious vulnerability degrees appeared in 2002 and 2006, and the degrees of 2006 was the most serious.(4) According to the formation mechanism and degrees of the vulnerability of geological environment, the control measures were proposed. First of all, the concept of prevention must be attentioned. Using digital coastal technology, coastal hazards defense system and the integrated management of incorporate coastal zone should be founded. The coastalzone management legislation should be improved. Based on implementing the combination of comprehensive and classification reduction of hazards, the sub-regional dynamic management should be brought into effect.