关键词: 地质灾害, 信息量法, 逻辑回归, 地貌单元, 易发性分区

Abstract:

The assessment of geological disasters mainly includes susceptibility assessment, hazard assessment, vulnerability assessment and risk assessment. The first two just reflect the geological disasters’ nature characteristics and theirs’ dangerous levels, what’s more, the remaining additionally describe geological disasters’ social characteristics and social potential losses on the basis of the first two. Actually, the susceptibility and hazard assessment could trace back to the 1970s, meanwhile, with the rapid development of GIS technology and high precision geotechnical physical model after 1990s, the research about geological disasters’ dangerous levels also step into a rapid development stage. On the whole, susceptibility assessment of geological disasters statically reflect the probability of geological disasters’ occurrence in view of the basic geological environmental conditions (internal control factors). On the other way, hazard assessment of geological disasters additionally takes external factors (time probability etc.) into account and responds the probability of geological disasters’ occurrence. Thus it can be seen that susceptibility assessment is the most fundamental research work in hazard or risk assessment and directly describes geological disasters’ inoculation situation. Nowadays, with the popularization and deepening of regional geological disaster risk assessment and zoning work, in view of small area, especially for small mountainous area or small populated area, the susceptibility assessment to geological disasters becomes increasingly urgent and important. Based on the above situation, this article takes Wenchuan County surrounding area as the study object, taking grid unit and geomorphic unit as evaluation unit, using information value method and logistic regression method to take an analysis on the susceptibility zoning. According to the results of comparative analysis, in a small area, susceptibility zoning with geomorphic unit not only can better reflect the local comprehensive characters, make the evaluation results more close to the actual geological disasters distribution, but could get clear hierarchical level, and more effective for the application of the mathematical model. The conclusions is: in a small area, it will have a good applicability and plasticity for the susceptibility zoning which is based on the geomorphic unit and it is a beneficial attempt and inspiration for the geological disasters susceptibility mapping in the large scale.

Key words: geological disasters, information value method, logistic regression method, geomorphic unit, susceptibility zoning