Gravity Erosion And Sand Production Scale Effect Of Post-Earthquake Debris Flow Based On Multi-Source Remote Sensing Technology

After the Wenchuan earthquake,the frequent occurrence of geological disasters resulted in the phenomenon of strong collapse and landslide gravity erosion and sediment production,which seriously affected the production and construction activities in the disaster-stricken areas and endangered the safety of people’s lives and property.The terrain in the area is complex,gravity erosion is active,and the sediment production process is complex,which is difficult to observe,test,and model.It is difficult to obtain quantitative parameters such as gravity erosion sediment production and erosion.The research on the analysis of erosion and sediment production in small watersheds and watersheds is increasing year by year,but there are few studies on the characteristics of gravity erosion and sediment production at different scales after the earthquake and the relationship between the characteristics.In this paper,multi-dimensional feature information such as spectrum,texture,index,and terrain are used,and after feature optimization is carried out by correlation and importance analysis,support vector machine is used to identify gravity erosion areas,and D-In SAR and Offset Tracking radar remote sensing technologies are combined to construct post-earthquake gravity Erosion deformation field model,combined with slope-small watershed-watershed unit to extract characteristic parameters such as gravity erosion and sand production,accumulation and sand production,to study the scale characteristics of gravity erosion and sand production at different scales,and use the neural network model to analyze The relationship between erosion and sediment yield characteristics at different scales was carried out.The results show that: 1)The sediment production,erosion and accumulation of the slope all increased with the increase of the slope area,and the sediment production of the slope remained stable after the slope area was greater than 80,000 square meters;The increasing rate of the erosion amount gradually slowed down with the increase of the slope area,while the increasing rate of the accumulation amount increased with the increase of the area.The fitting accuracies are 0.8156,0.8939 and 0.9419,respectively,indicating that there is a certain exponential relationship between the slope characteristic parameters and the slope area.2)Both the sediment production and erosion in small watersheds show an increasing trend with the increase of the small watershed area.Although the accumulation amount has a positive correlation with the increase of the area,its growth rate is obviously higher than that of sediment production.It has a certain linear relationship,and its fitting accuracy is good,which are 0.9882,0.8113,and 0.8091,respectively.3)The sediment production,erosion and accumulation in the watershed show that they increase with the increase of the watershed area.However,the growth rate of accumulation is obviously slower than that of sediment production and erosion.The precisions are 0.6835,0.7996,and 0.8767,respectively,indicating that the fitting effect is relatively general.4)Introducing influencing factors of different scales(such as perimeter,slope,relative height difference,etc.)and area and characteristic parameters of erosion and sediment production to build a 3D model,the model fitting accuracy is mostly improved compared with the 2D fitting accuracy,indicating that The generation of gravity erosion and sediment production is the result of the mutual coupling and interaction of many factors.