Abstract
Earthquakes and seismically-induced landslides accelerate carbon export from mountains by eroding hillslope soil carbon. However, a quantitative understanding of their net contribution to carbon cycling remains incomplete. Using the 2008 M(w) 7.9 Wenchuan Earthquake which generated the largest landslide volume in recent history, we quantify its carbon mass balance accounting for storage, loss, and transport within the ensuing sediment cascade. Thanks to post-event revegetation and extensive intermontane sediment storage, we show that the earthquake boosted Longmenshan carbon mass by ~10%. Given the stability of these deposits and low rates of carbon export, we anticipate this landslide carbon will persist for centuries to millennia before gradually declining. In effect, we demonstrate that earthquakes and landslides function as capacitors, regulating carbon storage and discharge across mountain belts over time. This suggests frequent landslides in seismically-active mountains may lead to a net carbon sequestration, providing a critical and direct link between tectonics and the carbon cycle.