利用Newmark方法进行地震滑坡制图——以映秀研究区为例
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摘要
2008年汶川5.12地震触发了大量滑坡,这些滑坡所造成的损失甚至超过地震本身。在地震区映秀,获取了地震边坡稳定性分析所需的地震滑坡编目图、强震监测数据、1:50000地质图、岩组单元的物理力学数据及基于1:50000地形图得到的DEM数据,所有这些数据都通过GIS(ilwis3.6)进行了矢量化及栅格化(10m)处理。基于上述数据,利用Newmark方法对每个单元格的变形及位移进行计算分析,然后通过Newmark位移与地震滑坡编目图进行对比分析,建立边坡失稳概率与Newmark位移之间的关系,用于地震滑坡预测及编图,为地震应急及灾后重建提供科学依据。
A number of landslides were triggered by the Wenchuan earthquake on May 12,2008.The damage caused by these landslides was even more than that of earthquake per se.In the Yingxiu area we have all of the data sets needed to conduct a rigorous regional analysis of seismic slope instability.These data sets include:(1) a comprehensive inventory of triggered landslides;(2) strong-motion records of the main shock;(3) 1:50,000-scale geologic mapping of the region,(4) extensive data on engineering properties of geologic units;and(5) digital elevation models produced by 1:50,000-scale topographic map.All of these data sets have been digitized and rasterized at 10 m grid spacing using ILWIS GIS software.Combining these data sets in a dynamic model based on Newmark's permanent-deformation(sliding-block) analysis yields estimates of coseismic landslide displacement in each grid cell.The modeled displacements are then compared with the digital inventory of landslides triggered by the earthquake to construct a probability curve relating predicted displacement to probability of failure.This probability function can be applied to predict and map the spatial variability in failure probability in any ground-shaking conditions of interest.We anticipate that this mapping procedure will be used to construct seismic landslide hazard maps that will assist in emergency preparedness planning and in making rational decisions regarding development and construction in areas susceptible to seismic slope failure.
A number of landslides were triggered by the Wenchuan earthquake on May 12,2008.The damage caused by these landslides was even more than that of earthquake per se.In the Yingxiu area we have all of the data sets needed to conduct a rigorous regional analysis of seismic slope instability.These data sets include:(1) a comprehensive inventory of triggered landslides;(2) strong-motion records of the main shock;(3) 1:50,000-scale geologic mapping of the region,(4) extensive data on engineering properties of geologic units;and(5) digital elevation models produced by 1:50,000-scale topographic map.All of these data sets have been digitized and rasterized at 10 m grid spacing using ILWIS GIS software.Combining these data sets in a dynamic model based on Newmark's permanent-deformation(sliding-block) analysis yields estimates of coseismic landslide displacement in each grid cell.The modeled displacements are then compared with the digital inventory of landslides triggered by the earthquake to construct a probability curve relating predicted displacement to probability of failure.This probability function can be applied to predict and map the spatial variability in failure probability in any ground-shaking conditions of interest.We anticipate that this mapping procedure will be used to construct seismic landslide hazard maps that will assist in emergency preparedness planning and in making rational decisions regarding development and construction in areas susceptible to seismic slope failure.
引文
[1]Randall W.Jibson,Edwin L.Harp,John A.Michael A method forproducing di gital probabilistic seismic landslide hazard maps[J].Engineering Geology 58(2000)271-289,2000.
[2]Mario Parise,Randall W.Jibson,A seismic landslide susceptibilityrating of geologic units based on analysis of characteristics of landslidestriggered by the 17January,1994 Northridge,California earthquake,Engineering Geology 58(2000)251-270,2000.
[3]Alberto Reficea,Domenico Capolongob,Probabilistic modelingofuncertainties in earthquake-induced landslide hazard assessment,Computers&Geosciences 28(2002)735-749,2002.
[4]Kuo-Jen Chang,Alfredo Taboada,Ming-Lang Lin,Rou-Fei Chen,Analysis of landsliding by earthquake shaking using a block-on-slopethermo-mechanical model:Example of Jiufengershan landslide,central Taiwan,Engineering Geology 80(2005)151-163,2005.
[5]Randall W.Jibson,Regression models for estimating coseismiclandslide displacement,Engineering Geology 91(2007)209-218,2007
[6]Wen-Fei Peng,Chein-Lee Wang,Shih-Tsu Chen,Shing-Tsz Lee Aseismic landslide hazard analysis with topographic effect,a case studyin the 99 Peaks region,Central Taiwan,Environ Geol,2008.
[7]胡元鑫,刘新荣,葛华.5.12汶川地震映秀极震区地震滑坡编目分析,HU Yuan-xin,LIU Xin-rong,GE Hua,Analyses of earthquake-induced landslide inventory in Yingxiu meizoseismal area of 5.12wenchuan earthquake,重庆大学学报,2011.
[2]Mario Parise,Randall W.Jibson,A seismic landslide susceptibilityrating of geologic units based on analysis of characteristics of landslidestriggered by the 17January,1994 Northridge,California earthquake,Engineering Geology 58(2000)251-270,2000.
[3]Alberto Reficea,Domenico Capolongob,Probabilistic modelingofuncertainties in earthquake-induced landslide hazard assessment,Computers&Geosciences 28(2002)735-749,2002.
[4]Kuo-Jen Chang,Alfredo Taboada,Ming-Lang Lin,Rou-Fei Chen,Analysis of landsliding by earthquake shaking using a block-on-slopethermo-mechanical model:Example of Jiufengershan landslide,central Taiwan,Engineering Geology 80(2005)151-163,2005.
[5]Randall W.Jibson,Regression models for estimating coseismiclandslide displacement,Engineering Geology 91(2007)209-218,2007
[6]Wen-Fei Peng,Chein-Lee Wang,Shih-Tsu Chen,Shing-Tsz Lee Aseismic landslide hazard analysis with topographic effect,a case studyin the 99 Peaks region,Central Taiwan,Environ Geol,2008.
[7]胡元鑫,刘新荣,葛华.5.12汶川地震映秀极震区地震滑坡编目分析,HU Yuan-xin,LIU Xin-rong,GE Hua,Analyses of earthquake-induced landslide inventory in Yingxiu meizoseismal area of 5.12wenchuan earthquake,重庆大学学报,2011.
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