Links between erosion, runoff variability and seismicity in the Taiwan orogen

The erosion of mountain belts controls their topographic and structural evolution(1 - 3) and is the main source of sediment delivered to the oceans(4). Mountain erosion rates have been estimated from current relief and precipitation, but a more complete evaluation of the controls on erosion rates requires detailed measurements across a range of timescales. Here we report erosion rates in the Taiwan mountains estimated from modern river sediment loads, Holocene river incision and thermochronometry on a million- year scale. Estimated erosion rates within the actively deforming mountains are high ( 3 - 6 mm yr(-1)) on all timescales, but the pattern of erosion has changed over time in response to the migration of localized tectonic deformation. Modern, decadal- scale erosion rates correlate with historical seismicity and storm- driven runoff variability. The highest erosion rates are found where rapid deformation, high storm frequency and weak substrates coincide, despite low topographic relief.