Landslide Disparities, Flume Discoveries, and Oso Despair

Abstract

Landslide dynamics is the branch of science that seeks to understand the motion of landslides by applying Newton's laws. This memoir focusses on a 40‐year effort to understand motion of highly mobile—and highly lethal—landslides such as debris avalanches and debris flows. A major component of this work entailed development and operation of the U.S. Geological Survey debris flow flume, a unique, large‐scale experimental facility in Oregon. Experiments there yielded new insights that informed development of mathematical models that were aimed not only at explaining landslide dynamics but also at evaluating landslide and debris flow hazards. The most sophisticated of these models, called D‐Claw, found its first practical application during investigations of the 2014 Oso, Washington, landslide disaster. That event provided indelible lessons about the utility and sociology of science in the real world. This article recounts a 40‐year effort to understand and predict the sometimes‐surprising dynamics of landslides and debris flows Key parts of this effort entailed development of the USGS debris‐flow flume and of numerical models informed by the flume experiments Application of this work to the disastrous 2014 Oso landslide highlighted the rewards and frustrations of using science in the real world