Research on the Deformation Pattern of Longriba Fault Zone Using River Drainage Pattern and GPS Data

This paper uses the Arcgis software to extract the catchment basins and its rivers in the Longriba fault zone, and uses the Topotoolbox tool to calculate the azimuth and deflection angles of the catchment basins and rivers. Combined with the kinematic characteristics revealed by GPS data, we discuss the control effect of tectonic strain on river drainage pattern. The results show that the shape of the larger first-order catchment basin in the study area changes from open to long and narrow along the movement direction of the block. In addition, along the fault zone to the distribution of Longriba fault zone, 17 secondary azimuth of catchment basin are mainly distributed in 0 ° and 350 °. The 7 secondary catchment basins along the middle section of the Longriba fault zone（North-west wall）are roughly oblique to the fault, showing systematic deflection and elongation along the strike-slip direction of the fault, indicating that they may have been affected by the strike-slip. The 10 secondary catchment basins along the north-east section of the Longriba fault zone（West wall）are nearly parallel to the fault, indicating that it may be dominated by the compression strain in the direction of the block movement.