Interpretation of the Spatial Distribution Characteristics of the Co-seismic Landslides Induced by the 1920 Haiyuan M81/2 Earthquake Using Remote Sensing Images1

摘要

Analyzing the spatial distribution characteristics of earthquake-induced secondary disasters based on advanced techniques is significantly important,especially in understanding the process of strong earthquakes in the Loess Pateau.Using ArcGIS,this study interprets multi-temporal high-resolution satellite images,field investigation data,and historical seismic records.Major conclusions are obtained as follows:①Landslides induced by the Haiyuan earthquake are mainly distributed in the intersection area of the end of the Haiyuan fault and Liupanshan fault,as indicated by multiple dense distribution centers;②The landslide distribution of the Haiyuan Earthquake is determined by the distance to the fault,topographic relief,slope,lithology,and other factors.In detail,the closer the distance to the fault,the greater the density of the landslide.The greater the slope and relief of the terrain,the greater the density and the smaller the average area of a landslide.Compared with tertiary strata,Quaternary strata has a larger average area,and the density of the landslides is smaller;③The density curve of the death toll in the Haiyuan earthquake can be used as a reference for the distribution of co-seismic landslides.Several Haiyuan co-seismic landslides are distributed in the Tongwei landslide area;however,the major landslides here are induced by the 1718 Tongwei earthquake rather than the 1920 Haiyuan earthquake;④The co-seismic landslides of the Haiyuan earthquake exhibits the“slope effect”in the south-west plate of Haiyuan fault,presenting the dominant sliding direction towards the fault and epicenter;however,the“slope effect”is not evident in the northeast plate of the fault.