Debris flows in Mozi gully, China following the 2008 Wenchuan earthquake

Abstract

Numerous landslide that provided abundant material for the mobilization of debris flows were triggered in the Mozi gully on the right bank of Mingjiang River in response to the M8.0 Wenchuan earthquake of May 12, 2008. Following the earthquake, debris flows occurred during July through September of 2008 and again in September of 2009. Five of these events blocked the Mingjiang River. This paper estimates the volume of landslide material contributed to the valley by comparing remote sensing images before and after the quake, and analyzes the resultant landslide dams to estimate the volume of material necessary to block the channel. Return periods of debris flows with varying peak discharges are estimated based on empiri-cal formulas and field surveys of the valley.