Research On Surface Deformation Monitoring Based On Time Series InSAR Technology In Dongchuan District Of Kunming

Dongchuan district of Kunming city is located in the northern part of the YunnanGuizhou plateau and Xiaojiang fault zone.Due to its special geographical location and unique texture and environmental conditions,earthquakes,debris flows,landslides and other geological disasters in this area have become the main factors restricting the development of this area.In this paper,time-series In SAR technology was used to study the surface deformation of urban areas,surrounding valleys and mining sites in Dongchuan district,Kunming city,Yunnan province.Based on the deformation results and combining with the activity characteristics,trend and disasters of Xiaojiang fault zone,the factors causing the deformation in this area were analyzed.a deeper understanding of disaster prevention and geological activity prediction in the area.Synthetic aperture radar interferometry(In SAR)not only inherits the characteristics of low cost and large area of optical remote sensing,but also has all-day and all-weather imaging capabilities,making microwave remote sensing an increasingly advantageous measurement method.Many domestic and foreign scholars' research in recent years has pushed the microwave remote sensing technology to an unprecedented new height,making the technology not only make achievements in topographic mapping,but also have great advantages in observing deformation caused by irresistible natural action,such as volcanic movement,geological tectonic movement and glacier movement.Microwave remote sensing is almost the most effective method in the study of classification of terrestrial classification.As a relatively efficient means of lidar technology,the SBAS-In SAR technology mainly selects image pairs with short space-time baselines for interference,which effectively solves the limitation of D-In SAR due to spatiotemporal incoherence and is widely used in surface slow deformation monitoring.In this paper,ENVI SARscape platform and sentinel-1 image data,coupled with SRTM 30-meter precision DEM provided by NASA and Google earth high-resolution image data,were used to monitor the slow surface deformation in Dongchuan urban area and its vicinity.Multiple experiments and analyses were conducted on the changes of image interference quality,and the following results were obtained:(1)due to the influence of the north-south strike of Xiaojiang fault zone,the main deformation occurred in the north-south strike,and the SAR data was not sensitive to the deformation in this direction,while the SBAS-In SAR had better effect here than the traditional D-In SAR method.To verify that the SBAS-In SAR technique has a profound development potential in the long-term monitoring of surface deformation in areas with frequent geological activities.(2)D-In SAR was used to analyze the factors affecting the coherence,and the selection of threshold was explored through experiments to optimize the process of the SBASIn SAR technology in Dongchuan region.The experimental results showed that the untangling effect was poor or could not be untangled in the areas with high vegetation coverage,while in the Dongchuan urban area,the coherence of the alpine bare soil region was better,and the deformed settlement points were dense and clear,which proved the influence of the ground object type on the image-to-coherence.(3)different filters and different unwrapping methods were used to carry out experiments in areas with serious soil erosion and large slope fluctuation by using the SBAS-In SAR technology.The comparison results showed that the Goldstein filter method could better control noise and the unwrapping method of the minimum cost flow had better unwrapping accuracy.(4)the spatial and temporal distribution rules of Dongchuan and its adjacent areas were discussed by using the SBAS-In SAR technology,and the geological activity inducements such as the subsidence of Dongchuan urban area and the subsidence and uplift of the nearby valley area of Xiaojiang fault zone were analyzed,and the frequent occurrence of geological disasters was considered to be closely related to the geological conditions in this area.By analyzing the time series of typical areas such as Dongchuan main city,Tangdan village and Luoxue copper mine,it is concluded that surface monitoring based on time series is of guiding significance in the exploration of the periodicity of geological disasters.