Landslide Hazard Zoning Based On Information Model And Landscape Pattern Analysis

Landslide is subject to the combined effects of multiple factors with complex spatial and temporal variability of ecological processes on land, and human-induced land-use activity is one of the causes of landslide hazard;on the other hand land-use change in the way will inevitably lead to regional landscape pattern change while landscape pattern and slope, slope length and soil properties were closely related, so the landscape will affect the spatial pattern of landslide hazard and a series of ecological processes. Through the landslide hazard areas and landscape pattern analysis in different risk levels, it's significant to understand and grasp the heterogeneity discipline of landslide disasters in different land use extent, manner and measures configuration, and can more effectively guide the adjustment of agricultural structure and optimize the layout of land use, while on ecological restoration and land resources in sustainable and equitable use has important practical significance.Based on in-depth study of landslide risk zoning , landscape pattern analysis theory and research on the basis of our predecessors of scientific research, this study first combine with the actual situation of the study area and use GIS as a platform to establish research of regional landslide hazard spatial database, and select the influential key factors as evaluation indexes; then it combined the certainty factor (CF) and information model to divide the landslide hazard areas; last, it analyses the landscape pattern characteristics in different landslide hazard zoning in support of Fragstats to explore the relationship and discipline between landslide risk and landscape pattern, which obtain the following conclusions:(1) The key impact factors in the landslide hazard have different effects to the sensitivity of landslide disasters varying. Sedimentary rock category lead to instability of the landslide with the highest certainty, and in the context of a certain slope, with the increasing of the slope, the landslide instability is more serious; in slope category, southwest and northwest slope is more easily lead to landslide instability; the purple soil in soil types is most sensitive to the occurrence of landslides, followed by paddy soil , red soil, red soil upon, yellow, and other soil types; while the moderate slope of mountains and hills of the terrain lead to a higher certainty of landslide instability.(2) In the landslide risk scoring chart that is overlaid with the information of the the impact factors, the study area region has been divided into five risk levels according to the principle of landslide hazard area. Among them, there are 271 landslide disasters in the high-risk and high risk areas, accounting for 84.69% of the total landslide, and the number of landslide disasters point is up to 1.707 / 103ha in the high risk unit area within the region. While only 2 points are in the low degree of risk of landslide hazard areas and disasters in per unit area point to 0.030 / 103ha, so the district results match the actual situation of the study area.(3) At the landscape level, the landscape diversity and fragmentation decreases along with the extent of the increase in landslide risk, while the aggregation levels increases along with the extent of the increase in landslide risk, that is, with the risk rating increasing, the landscape diversity and spatial heterogeneity is smaller. Further analysis shows that this is related to the internal factors of landslide and the scope of human activity .on one hand the landslide always occurred in a certain slope of the mountain hills, unlikely to occur in flat areas, on the other hand human land-use activities generally focused on flat land and gentle slope areas while the higher slope areas are less interfered for mainly woodland and garden covered on, that is, land-use activities is less affected to the occurrence of landslide disasters.(4) At the level of landscape types, there is a certain degree of correlation between landslide risk levels and the index of landscape size, shape, degree of fragmentation, aggregation. The relevance of the different landscape indices in the same landscape with the landslide risk levels is different, while landscape indices of different landscape types in the same landslide risk level is also different.(5) As the land use and the utilization has been influenced by geological features, so as the external factors of landslide, land-use has had induced effects on the landslide only when there is a certain disaster-pregnanted conditions in the study area. It needs to combine the internal factors of landslide and consider more aspects in order to form a system of factor analysis and reach the right conclusion with the impact factor analysis.