| Ailao Mountain has complex landform,active geological structure movement and frequent landslide disasters,which bring huge casualties and property losses to the county every year.Through multiple rounds of geological disaster survey in Yunnan Province,more than 20,000 landslide hazard spots have been recorded.However,it is found through statistical survey that only 20% of the landslides that occur and cause harm every year are in the hidden danger points of landslide disasters.In order to increase the timeliness of landslide hazard,it is necessary to increase the speed of landslide hazard identification and reduce the identification period.Therefore,it is urgent to develop In SAR technology for early identification,early warning and prevention of landslide hidden danger.The technique of Interferometric synthetic aperture radar(In SAR)is a new kind of remote sensing earth observation technique,which can be well applied to landslide identification.Compared with the traditional landslide hidden danger investigation method,the monitoring period is short,the scope is wide,the weather image is small,and the monitoring cost is low,which can reduce the consumption of human and financial resources.In this paper,Sentinel-1A image was used as the basic data and Yuanyang County in the southern section of Ailao Mountain was taken as the research area to establish an early identification method of landslide hidden danger combined with optical remote sensing and landslide hazard pregnancy conditions,to carry out a county wide identification of landslide hidden danger in Yuanyang County,and to monitor typical landslides.This paper studies from the following aspects,and the research contents and conclusions are as follows:1.In this paper,83 ascenders and 80 Sentinel-1A images covering Yuanyang County from March 2019 to March 2022 were selected for cropping and interference processing by SBAS-In SAR technology.The surface deformation information of Yuanyang County was obtained by Arc GIS,and the area with abnormal settlement rate was delineated as the dangerous point of deformation.A total of 80 dangerous points were identified in this paper.2.On the basis of the delineated danger points,this paper uses optical remote sensing images to identify the hidden danger of landslides.Based on the identification mark of landslide optical image interpretation in Yuanyang County,this paper investigates whether the deformation danger point is landslide danger point.Through interpretation and judgment,35 abnormal points of settlement rate in Yuanyang County are classified as landslide danger points,and the remaining 45 can not be determined as suspected landslide points.3.For suspected landslide points,this paper determines the landslide hazard pregnancy conditions of landslide points through analysis,such as slope,slope aspect,relief degree,roughness,land use type,structural conditions and engineering geological rock groups as identification and screening values,establishes the landslide pregnancy conditions discrimination method,makes comprehensive judgment on suspected landslide points,and finally determines 40 landslide hidden danger points.4.Based on the identified landslide danger points and hidden danger points,this paper selected three typical landslides in the research area of Yuanyang County for monitoring and field investigation.Optical remote sensing image interpretation and time series deformation analysis were carried out for the three landslide points respectively,and then field investigation was carried out.The results show that there are signs of sliding in the three landslides,but the deformation analysis of the time series shows that the surface deformation tends to be stable,but the subsequent sliding does not rule out.Except the Yanzizoucun North landslide,the other two landslide points have been carried out prevention and control measures,monitoring and warning.But Yanzizou Village north landslide without disaster prevention measures,in the future need to strengthen patrol warning. |
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