Air drag controls the runout of small laboratory landslides

TL;DR

This study investigates how air drag influences the runout distance of small laboratory landslides through experiments and scaling analysis, revealing the critical factors that determine landslide extent.

Contribution

It identifies the combined effects of air drag, grain size, and fall height as key determinants of landslide runout, providing new insights into scaling laws for small landslides.

Findings

Air drag significantly affects small landslide runout.

A minimum landslide size is necessary to observe scaling effects.

Scaling analysis links grain size, fall height, and air drag to runout distance.

Abstract

Laboratory granular landslides are smaller-scale, simplified, yet well-controlled versions of larger and often tragic natural landslides. Using systematic experiments and scaling analysis, we quantify the influence of grain size, fall height, and landslide volume on runout distance. We also determine the minimum landslide size required to observe this scaling, which we find is set by a combination of air drag, grain size, and fall height.