Influence of tectonic damage on erosion and topography of eastern Tibet

Abstract:

Tectonic deformation can influence spatiotemporal patterns of erosion by changing both base-level and the mechanical state of bedrock. Although base-level change and the resulting erosion are well understood, few studies have quantified the impact of tectonic damage on bedrock erodibility and surface processes. Eastern Tibet, a tectonically active region with diverse lithologies and multiple active faults, provides a suitable field site to understand how tectonic deformation controls erosion process and topography. Here, we present two studies that examine the interplay between tectonic damages, erosion, and topography in eastern Tibet. First, we examine the impact of fault damage on erosion and topography by quantifying erosion coefficients and comparing them with distance to major faults. Our work shows a two-fold increase in erosion coefficients between basins within 15 km of major faults and those beyond 15 km, suggesting that tectonic deformation through seismic shaking and rock damage significantly affects erosion and topography. Second, we examine how topographic stress, resulting from the interaction between tectonic stress and topography, influences the magnitude of landslide erosion at landscape scales by modulating the extent of subsurface weathered zones. Our work shows field-based, quantitative evidence of tectonic damage impacts on erosion and topography of eastern Tibet, which has important implications for landscape evolution and natural hazards.