| China is a country with frequent earthquakes.Earthquakes will induce a large number of geological disasters.Earthquake-induced geological hazards are characterized by large scale and long movement distance.InSAR,UAV and field investigation were used to identify 107 geological hazards,including 82 collapses and25 landslides.ARCGIS software is used to study the development and distribution of geological hazards in the study area.According to the characteristics of the development and distribution of geological hazards in Songpinggou,an evaluation system for the susceptibility of geological hazards in strong earthquake area is established,and the Jiuzhaigou earthquake is taken as an example to verify the system.The main conclusions are as follows:(1)The multi-source information geological hazard identification method based on BKS fusion algorithm and decision matrix algorithm can make the accuracy of hazard identification more than 70%.Through the application of disaster identification in Songpinggou,Dixi,107 geological hazards were identified,including 82 collapses and 25 landslides.According to the number and scale of geological hazards from strong to weak,the study can be divided into four regions with different hazard grades:comparative field area,United Village area,Songpinggou area and Longchi area.(2)Establishing a theoretical system of multi-source information recognition for geological hazards in strong earthquake areas,and establishing four basic classifiers according to multi-source information and characteristics of geological hazards.It is difficult to obtain high recognition accuracy of geological hazards by using a single basic classifier,but according to the complementarity of each single classifier,other features can be removed to achieve high accuracy recognition of geological hazards.Through screening classifier groups.The combination reduces the amount of calculation,and uses criterion matrix and behavior knowledge space algorithm to fuse classifiers,which effectively improves the recognition accuracy of geological hazards.(3)The damage characteristics and formation mechanism of typical landslide and collapse geological hazards in the study area are analyzed.Coseismic geological hazards:Tuanjiecun landslide,Yinpingya landslide and post-earthquake geological hazards:Xinmocun landslide and collapse along Highway G213 are selected for analysis.Four geological hazards are located in the seismic intensity area of the Tiexi earthquake_.During the process of intense energy release from the earthquake,the Tuanjiecun landslide and Yinpingya landslide are directly destroyed.At the same time,the rock mass of the slope where the Xinmocun landslide and the collapse along National Highway G213 are located is damaged by seismic cracking.Under the combined action of long-term self-weight,weathering erosion,precipitation and multiple earthquakes,the Xinmocun landslide is broken.The collapses along the bad and G213 lines are close to destruction(now some measures have been taken to control them).(4)ARCGIS was used to study the distribution of landslides and collapses.Geological hazards in the study area mainly occur in slopes with slope gradient of 30?50.Geological hazards are more frequent in the study area at altitudes of 2600-3000m.Large-scale geological hazards mainly occur in slopes with south slope orientation and east slope orientation.Geological hazards in the seismic intensity area of Dixi earthquake are the largest and the largest in number.There are more geological hazards in the strata of Zagunao Formation(T3z)and Juju Formation(T3zh);the closer to the fault zone and water system,the more geological hazards there are and the larger the scale.(5)To study the quantity(N)and area(S)of geological disaster development in Songping Gully,the number(N)and area(S)of geological disaster development in Songping Gully,the distance(Dw)from Songping Gully,and the distance(Dr)from Songping Gully and the distance(Dw)from Songping Gully and fault zone.The relationship is as follows:S=587.67ln(Dw)+905.41(R~2=0.9612,Dw?4km)?N=23.73ln(Dw)+75.396(R~2=0.9832,Dw?4km);S=338.51ln(Dr)+1131.6(R~2=0.9781,Dr?5km)?N=36.329ln(Dr)+53.815(R~2=0.9539,Dr?5km),the closer to Songpinggou fault and river system,the more geological hazards developed.(6)Eleven evaluation indicators,including elevation difference,slope,rock structure,rock dip angle and slope direction,rock dip angle,rock strength,weak structural plane strength,rock mass combination characteristics,distance from water system,seismic intensity and fracture distance,are selected to establish an evaluation index system for the susceptibility of geological hazards in strong earthquake areas.The weights of each evaluation index are obtained by using neural network model,in which the seismic intensity is relative to the water system.Geological hazards have the greatest impact in the study area.Taking the Jiuzhaigou earthquake as an example,the established model is verified.The geological hazards mainly occur in high-risk areas and high-risk areas,which indicates that the evaluation results of the established model are reliable. |
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