Exploring debris-flow processes with lidar and structure-from-motion

This talk will focus on the broad reach of point cloud datasets to better understand the life-cycle of mass movement (initiation, transport, and deposition), particularly related to debris flows. We will show how lidar data have been used to map debris flow initiation from shallow landslides after wildfire (San Gabriel Mountains, CA), and how lidar can reveal the frequency of step spacing in colluvial hollows, which contribute to debris flow initiation in burn areas (Front Range, Colorado). We will highlight how rapid (sub-second) lidar and structure-from-motion (SfM) collections were used in controlled experiments at the USGS debris flow flume to track changes in subsurface pore-pressure during landslide initiation, and to measure debris flow velocity during debris flow transport. In addition, we will demonstrate the use of lidar in mapping debris flow deposition, and how detailed topography can be used to highlight controls on flow dynamics that lead to deposition at various sites in California, Arizona, and New Mexico. Finally, we will show how SfM was used to understand how frost-weathering leads to channel refilling after debris flows at the Chalk Cliffs in Colorado.

Rengers F (2022) Exploring debris-flow processes with lidar and structure-from-motion, 16 March 2022.