Climate controls denudation rates from earthquake-triggered landslides in tectonically active mountains

Abstract

Against the backdrop of global climate change, the combined effects of frequent seismic activity, intense rainfall, and steep terrain have heightened landslide risks in the Himalayan region. Existing regional-scale studies have primarily focused on landslide denudation triggered by either rainfall or earthquakes, while investigations considering their combined influence remain limited. This study quantifies landslide denudation caused by the Wenchuan earthquake. It examines its relationship with the coupling of rainfall and seismic activity, thereby assessing the impact of rainfall–earthquake interactions on topographic evolution. Based on an analysis of landslide spatial distribution data, topographic indicators, rainfall, and earthquake parameters. We identified a significant nonlinear relationship between landslide denudation rates and topographic metrics. The coupling of rainfall and earthquakes substantially amplified landslide denudation rates. Rainfall continuously weakened rock mass strength through cyclical weathering and fluctuations in pore water pressure; when seismic events occurred, the equivalent rock strength further declined and surpassed the critical threshold for slope failure. This process increased landslide denudation rates and reduced the degree of nonlinearity, with the reduction being most pronounced under hard-rock conditions. Overall, this study enhances the understanding of erosion dynamics driven by extreme events in active orogenic belts.