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#           Using high sample rate lidar to measure debris-flow velocity and surface geometry      

      January 8, 2021    

Debris flows evolve in both time and space in complex ways, commonly starting as coherent failures but then quickly developing structures such as roll waves and surges. These processes are readily observed but difficult to study or quantify because of the speed at which they evolve. Many methods for studying debris flows consist of point measurements (e.g., flow height or basal stresses), which are inherently limited in spatial coverage and cannot fully characterize the spatiotemporal evolution of a flow. In this study, we use terrestrial lidar to measure debris-flow profiles at high sampling rates to examine debris-flow movement with high temporal and spatial precision and accuracy. We acquired measurements during gate-release experiments at the U.S. Geological Survey debris-flow flume, a unique experimental facility where debris flows can be artificially generated at a large scale. A lidar scanner was used to record repeat topographic profiles of the moving debris flows along the length of the flume with a narrow swath width (∼1 mm) at a rate of 60 Hz. The high-resolution lidar profiles enabled us to quantify flow front velocity of the debris flows and provided an unprecedented record of the development and evolution of the flow structure with a sub-second time resolution. The findings of this study demonstrate how to obtain quantitative measurements of debris-flow movement. In addition, the data help us to quantitatively define the development of a saltating debris-flow front and roll waves behind the debris-flow front. Such measurements may help constrain future modeling efforts.

## Citation Information

## Related Content

                  -              Data           
                  -              Connect           

June 22, 2020

####                 Lidar data for gate release experiment at the USGS Debris-Flow Flume 24 and 25 May 2017              

Natural Hazards Mission Area, Landslide Hazards Program, Geologic Hazards Science Center

#### Francis Rengers

##### Research Geologist

Landslide Hazards Program

frengers@usgs.gov

303-273-8637

#### Kate E Allstadt, Ph.D.

##### Research Geophysicist

Landslide Hazards Program

##### Research Geophysicist

Earthquake Hazards Program

kallstadt@usgs.gov

303-273-8570

#### Richard M. Iverson

##### Research Hydrologist Emeritus 

Cascades Volcano Observatory

riverson@usgs.gov

360-993-8920

#### Maciej K Obryk, Ph.D.

##### Research Hydrologist

Cascades Volcano Observatory

mobryk@usgs.gov

360-993-8929

## Related Content

June 22, 2020

####                 Lidar data for gate release experiment at the USGS Debris-Flow Flume 24 and 25 May 2017              

Natural Hazards Mission Area, Landslide Hazards Program, Geologic Hazards Science Center

#### Francis Rengers

##### Research Geologist

Landslide Hazards Program

frengers@usgs.gov

303-273-8637

#### Kate E Allstadt, Ph.D.

##### Research Geophysicist

Landslide Hazards Program

##### Research Geophysicist

Earthquake Hazards Program

kallstadt@usgs.gov

303-273-8570

#### Richard M. Iverson

##### Research Hydrologist Emeritus 

Cascades Volcano Observatory

riverson@usgs.gov

360-993-8920

#### Maciej K Obryk, Ph.D.

##### Research Hydrologist

Cascades Volcano Observatory

mobryk@usgs.gov

360-993-8929

### Contact

#### Geologic Hazards Science Center

1711 Illinois St.Golden, CO80401United States

303-273-8500