Study On The Spatial Characteristics Of Coastal Land And Vulnerability Risk Zoning Of Disaster Bearing Body

The frequent occurrence of Coastal Zone Disasters brings great losses to the disaster-bearing bodies on both sides of the coastal zone.It has important significance for the spatial planning of coastal zone to understand the relationship between the types of coastal zone disasters and regional vulnerability,divide the zones according to vulnerability,improve the capability of disaster assessment,effectively distinguish the driving factors of regional vulnerability,and formulate different disaster prevention strategies according to regional characteristics.With the support of Guangxi innovation driven development project "Beibu Gulf marine ranch geographic spatiotemporal data grid intelligent service platform R & D and demonstration application"(No.2018AA118004),the regional vulnerability research on Longmen port land and sea area was carried out.Based on the literature and field investigation,the regional vulnerability research and marine aquaculture disaster damage research were carried out to build a small scale Index system of regional vulnerability in land area.According to the system,the regional vulnerability level of different regions is calculated,and the level of marine aquaculture disaster loss is evaluated.The calculated results of marine aquaculture loss can be used as a scientific basis for the assessment of risk zoning of coastal zone and the promotion of comprehensive utilization of space.The main conclusions are as follows:(1)The main disaster causing factors of regional vulnerability are determined by the primary and secondary relationship between physical vulnerability and social vulnerability.When the resistance of social system exceeds that of environment,the leading disaster causing factor is social vulnerability;When the resistance of social system is equal to that of environment,the regional leading disaster causing factors are composed of social vulnerability and physical vulnerability;When the environmental capacity is greater than the social system resistance,the physical vulnerability becomes the leading regional disaster causing factor.According to the characteristics of different forms of regional vulnerability,the disaster prevention strategy should be inclined to the prevention and control of the leading disaster causing factors.(2)There is a positive correlation between regional disaster intensity and disaster level.Through the regional disaster fitting analysis of Longmen port town caused by "weimazon" in 2014,it is found that the more shrimp ponds there are in the small area,the higher the disaster loss rate is,and the higher the regional vulnerability is,the higher the disaster loss rate is,and the degree of disaster loss fitting is positively related to the degree of regional vulnerability.(3)In the five regional disaster levels,Longmen port town land use has a higher suitability.The suitability of land use is calculated under different regional vulnerability levels,and the suitability of land use under different regional vulnerability levels is analyzed.The conclusion is as follows: land use in Longmen port town has high suitability under different regional vulnerability levels,and the limiting factors of critical suitability are slope and elevation.Longmen port town's land use is divided into ring layers according to the offshore distance,which are divided into I to V levels,corresponding to 0-400 M,400-800 m,800-1200 m and 1200-1600 m respectively.Among them,class I ring layer is the most abundant in land use,with the highest proportion of forest land and breeding pond area in each ring layer.The relationship between land use seaward and offshore distance is: high low high.(4)High salinity sea water is the key factor of oyster death in large area.The suitable salinity range of oyster culture in spring is between 14 ? and 24 ?.Based on the data of oyster death in the research area and the data of seawater quality in the breeding area,the relationship between the mortality of aquatic products and seawater salinity,p H value,dissolved oxygen,etc.is plotted,the water quality range suitable for oyster survival is evaluated,and the oyster preservation area in spring in the research area is delimited.(5)Comprehensive vulnerability is restricted by regional vulnerability and land use vulnerability.Through the superposition calculation of regional vulnerability and land-use vulnerability,the comprehensive vulnerability spatial distribution is obtained.From figure 5-1,it can be seen that the regions with high regional vulnerability and high land-use vulnerability have relatively higher comprehensive vulnerability,lower regional vulnerability and high land-use vulnerability,and the regions with moderate comprehensive vulnerability and high proportion of land-use vulnerability have comprehensive vulnerability Higher vulnerability.