SEDIMENT FLUX FROM A MOUNTAIN BELT DERIVED BY LANDSLIDE MAPPING

In humid uplands landsliding is the dominant mass wasting process. In the western Southern Alps of New Zealand landslides are scale invarian t and have a power-law magnitude frequency distribution. Independent s tudies from other regions suggest that this is a general property of l andsliding. This observation is of critical importance to the evaluati on of the impact of events of different length scales over different t ime intervals on landscape evolution. It is particularly useful when e stimating regional geomorphic rates, because it constrains the frequen cy and overall significance of extreme events, which cannot otherwise be evaluated. By integrating the complete response of the system, we e stimate the regional denudation rate due to landsliding to be 9 +/- 4 mm yr(-1). Sediment discharge from the western Southern Alps is domina ted by landslide-derived material.