Large earthquakes cause rapid denudation of hillslopes by triggering thousands of coseismic landslides. The sediment produced by these landslides is initially mobilised out of the landscape as a cascade of unknown magnitude. This cascade dramatically enhances local erosion rates before rapidly returning to pre-earthquake levels. Identifying the individual processes of this cascade and estimating the volume of sediment they mobilise is crucial to determining the timescales over which earthquakes can influence hazards and sedimentary systems. Here we present a fully constrained sediment budget of the first decade after the 2008 M_w7.9 Wenchuan earthquake. With this budget we identify the key erosion processes within the post seismic sediment cascade and constrain estimates of the volume of sediment removed from the landscape. With these estimates we find that over 90% of the coseismically generated sediment remaining on the hillslope 10 years after the earthquake. Despite the large volumes of sediment on the hillslope, we observe an order of magnitude decrease in the erosion rate of the epicentral area. Debris flows are the key erosional mechanism of the coseismically generated sediment as erosion rates are correlated with debris flow frequency. Erosion rates likely remain elevated for several decades however, the rapid stabilisation of the sediment following the earthquake suggests large volumes of coseismically generated sediment can remain in orogens for hundreds or thousands of years. In the most tectonically active regions, the long residence times of coseismically generated sediment could significantly reduce bedrock incision rates in channels altering long term erosion rates.