Tectonic Interpretation And Activity Evaluation Of Daxihe River Basin Based On Multi-source Data

Structural interpretation is a very important part of geological mapping,but the point-line observation method used in traditional geological survey is vulnerable to complex topography,and remote sensing technology has been widely used in the field of geological survey because of its true,objective and comprehensive characteristics.At present,a large number of structural extraction studies are mainly carried out in the exposed areas of bedrock,and there are few studies on structural interpretation of deep covered areas.For the concealed structures with low surface outcrop,it is difficult to meet the real demand because of the poor adaptability of traditional bedrock structure interpretation.The study area of this paper is that the Daxihe River basin is located in the south of Ordos block,north of Weibei uplift,and the loess is widely distributed in the whole area,which is a serious area of soil erosion.In this area,seismic activity is active,geotectonic is complex,neotectonic movement is strong,and river erosion is remarkable.In this paper,remote sensing and geographic information system are used to study the tectonic activity in Daxi river basin.On the one hand,the Optimum Index Factor,Principal Component Analysis and Band Math are used to enhance the visual effect of the images.Then,the spatial location of linear structures is located and verified with geological data.On the other hand,the tectonic features are studied deeply,and the degree of tectonic activity in the study area is analyzed quantitatively by multi-group river geomorphologic parameters,and the significance of the new tectonic movement indication is discussed.The main points of view are:(1)The adaptability of conventional bedrock structural interpretation marks in loesscovered areas is poor.By analyzing the pattern of geomorphology and water system and giving full play to the role of indirect interpretation mark,the effect of structure extraction of coverage area can be improved effectively.(2)The index of relative active tectonics value is 1.068?2.897,and the faults are active,the tectonic uplift rate is higher in the eastern margin than the western,and the southern margin than the northern.The tectonic activities dominate the shape of longitudinal profile and the framework of drainage system in this basin,the basin inclines to the left side greatly,and the faults are active.This study fully demonstrates the advantages and broad prospects of remote sensing in geological structure research,and also plays an auxiliary role in regional geological background,structural activity analysis and disaster prediction.(3)There are asymmetric development phenomena on the north and south banks of the basin,the geomorphology is mainly controlled by tectonic activity.(4)Based on the interpretation of tectonic spatial distribution,this paper introduces the river geomorphologic parameters,constructs the activity evaluation model,and carries on the visual partition of tectonic activity intensity grade.