Study On Scale Effect Of Regional Geological Hazard Assessment

Geological hazard is a common natural phenomenon, which is occurred from the geological body that is impacted by the induced factor, such as human activity, precipitation and so on. Thence the study of geological hazard evolution is mainly analyzing the mechanism that the influencing factors impact on the geological hazard. So this kind of mechanism includes not only the status (is weight) of the influencing factors of geological hazard evolution and occurrence, but also mutual impacting mode among the several of influencing factors. Presently, the main geological hazard assessment applications mainly include the numerical simulation model based on physical model, the mathematical statistics methods based on probability, and the qualitative and semi-qualitative method which based on them. However, there generally are a series of very harsh boundary conditions of numerical simulation model, and mainly applied in the single geological hazard assessment; and to the regional geological hazard assessment, because the background of the study area is generally very complicated, and the scale of it is always very large, so that it unable to applied the simulation model to assessment, and the mathematical statistics method is the most important application which is applied to assess the regional geological hazard.The regional geological hazard assessment should depend on the specific spatial and temporal scale. Firstly, the geological hazard, as a natural phenomenon, its own evolution and occurrence intrinsically contain the spatial and temporal characteristics inevitably; secondly, the influencing factors which are used in assessment, such as the lithology, geological structure, topography, weather condition and so on also contain the spatial and temporal scale. Thence, the geological hazard assessment is inevitably impacted by the scale effect, and the fundamental reason of it is the nonlinear evolution in the temporal scale and the heterogeneity in the spatial scale of the geological hazards. However, it’s different from other subjects, such as hydrology, geography and so on, the scale effect of regional geological hazard assessment contains not only the scale effect of the subjects themselves which should be involved in assessment, but also its unique characteristics, because the regional geological hazard assessment is a technology which should involved in many subjects. The scale effect of regional geological hazard assessment is the uncertainty of the assessment result, which is caused by the application of the information which owns different spatial and temporal scale to analyze in the regional geological hazard assessment. It mainly contains the spatial effect, temporal effect and application effect. This thesis firstly analyzed the characteristics of these three kinds of scale effect based on the investigation of the foundational reason of each of them, and then explored the influence on the assessment result which was impacted by the modify of the weight of influencing factors (one of the spatial effect), the valid period of regional geological hazard assessment result (one of the temporal effect), and the associative effects to the assessment result of different regional geological hazard assessment applications respectively, and all of them combined with specific examples. Finally, the results of them showed that it should be considered the influence on the assessment operability and the accuracy of assessment result which was impacted by the scale effect when assessed the regional geological hazard risk.