Landslide types and geomorphic impact on river channels, Southern Alps, New Zealand

摘要

Interactions between large mass movements and alpine river channels significantly extend the range of geomorphic forcing mechanisms and hazards in mountainous environments. They encompass a range of phenomena such as catastrophic outburst floods from temporary landslide- or debris-dammed lakes. They also promote channel instability and metamorphosis due to excessive sediment loading, transformation of gravitational to long run-out flow movements on groundwater-saturated valley floors, and landslide-induced formation of steps, pools and riffles in the stream long profile. It is proposed that the geomorphic efficiency of landslide impact on alpine valley trains is not a sole function of landslide magnitude (e.g. volume), but also a result of topographic position, mode of failure, and the nature of the channel-hillslope coupling interface.