Rainfall Threshold Research Of Rainfall-induced Landslides In Tianshui Area

Tianshui area,which is covered by widespread unstable loess,has complex landform,altitude difference in great disparity and intense neotectonics movement.It also has abundant rainfall concentrating on summer and autumn.All of the above lead landslide to a common geological disaster in this area.In recent years,landslides caused by rainfall become a common occurrence,which brings severe influences to our life security and property security.This article will combine all kinds of landslide data with TRMM 3B42 rainfall data,research on the relationship of landslides and rainfall as well as the rainfall thresholds of rainfall-induced landslides.The main works and achievements are listed below.(1)By combining 317 existing landslides in some counties with TRMM 3B42 rainfall data,we discuss rainfall characteristics and landslide characteristics in this area and obtain the relationship of landslides distribution and multi-year average precipitation.(2)By combining 522 landslides in “7.25 group-occurring geological disasters” with TRMM 3B42 rainfall data,we respectively analyse the relationship of landslides distribution and 3d,15 d,30d previous accumulated precipitation and also establish a previous daily-accumulated precipitation--duration threshold model of large-scale group-occurring landslide disasters in extreme rainfall conditions.(3)By combining 34 landslides whose occurrence time and locations are known with TRMM 3B42 rainfall data,we analyse the temporal and spatial characteristics of landslides distribution and classify the rainfall-induced landslides.We also establish a rainfall intensity-duration threshold model and compare it to other-area thresholds and a global threshold and propose a way of supervising potential landslides dynamically.