A NOVEL LIDAR-BASED LANDSLIDE INVENTORY OF YELLOWSTONE NATIONAL PARK

Landslides are a globally pervasive and impactful geologic hazard, particularly in mountainous terrain. Steep slopes, extreme precipitation, unstable substrates, and seismic activity all make landslides a common feature of Yellowstone National Park. Yellowstone is among the most-visited national parks in the United States, funneling millions of people through narrow, winding roads that intersect landslide-prone terrain. Understanding the distribution of past landslides throughout the park is crucial for ensuring visitor safety and managing infrastructure, while also illuminating patterns of landscape evolution in this unique volcanic and post-glacial setting.

Landslide inventories summarize locations and characteristics of landslides and are foundational tools for assessing risk. Though several individual landslides have been identified and studied in Yellowstone, no systematic, park-wide inventory has been conducted. In the fall of 2020, the USGS collected 1-meter resolution, bare-earth LiDAR topography of the entire park, providing an unprecedented opportunity for mapping landslide scarps and deposits, particularly those obscured by forest cover.

This project combines LiDAR interpretation with field observations to create a GIS database of landslide scarps and deposits at a 1:4000 scale. In addition to cataloging location and size, the database classifies landslides by type and describes topographic and lithologic characteristics of the slopes in which they occur.

So far, the database contains more than 1000 landslides, hundreds of which have not been previously identified in existing publications. Landslide activity occurs largely outside of the caldera, clustered in the high relief areas around the margins of the park. Multiple generations of initiation and reactivation are often apparent, suggesting zones of chronic instability. Many of these zones of instability show a similar morphology, where movements initially fail as rotational slides and reactivate as flows.

We assume that visible deposits record all major movements that have occurred at least since the retreat of the Pinedale ice sheet ~15ka. We hope to use DInSAR to assess the activity state and temporal patterns of the LiDAR-mapped landslides to better understand drivers of contemporary mobility.