四川省典型区域滑坡、泥石流致灾临界雨量阈值确定方法

目的]确定四川省滑坡泥石流典型区域各个子区最关键的降雨因子,建立典型区域各子区临界阈值模型,为该区对滑坡、泥石流灾害进行有效预报提供科学依据.方法]利用1999 2014年四川滑坡泥石流灾情资料,确定出滑坡、泥石流的典型区域,根据典型区域各个子区的气候和下垫面条件,比较不同降雨因子组合的阈值模型,得到各子区最关键的降雨因子,建立典型区域各子区临界阈值模型.结果]平均降雨强度和峰值降雨强度是典型区域滑坡、泥石流阈值模型中的重要指标;诱发雨量多作为滑坡典型区域致灾临界阈值模型雨量指标,激发雨量只作为泥石流典型区域致灾临界阈值模型雨量指标;有效雨量可以在滑坡、泥石流典型区域值模型中应用.典型区域多采用多因子预报模型,只有汶川震区采用单因子预报模型,其临界阈值在震后呈现上升趋势.结论]不同降雨参数对诱发滑坡泥石流灾害的作用不同,典型区域中各子区建立的预报模型及得出的临界阈值也不同.多因子预报模型考虑了多种降雨参数,比单因子模型更客观.

Methods of Determining Rainfall Thresholds of Landslides and Debris Flows in Typical Region in Sichuan Province

Objective] We chose the most significant rainfall indicators of landslides and debris flows in typical regions and built a critical threshold model for each sub-region in typical regions to provide a scientific basis for effective prediction of landslide and debris flows.Methods] This study collected Sichuan''s geological disaster cases occurred in 1999-2014, to define the typical regions of landslides and debris flows in Sichuan Province. We compared the threshold models that are made up of different rainfall indicators in each typical region to construct our rainfall threshold models.Results] Average rainfall intensity and maximum rainfall intensity are used frequently as significant parameters in threshold models of landslides and debris flows in typical regions. Indirect rainfall is a precipitation indicator of landslides in typical region generally, direct rainfall is a precipitation indicator of debris flows just in typical region generally. Effective rainfall was adopted to the precipitation indicator both of landslides and debris flow threshold models in typical regions. Model with double factors were applied to most of typical regions of landslides and debris flows. Model with one factor was just applied to Wenchuan earthquake-stricken area, the critical threshold gradually raised from Wenchuan earthquake.Conclusion] Different rainfall factor has different effect on disasters, each typical region has its own optimum rainfall threshold model. Model with double factors is more objective than those with just one factor, as they contain more rainfall factors.