92-10 Comparisons of Historical and Event Landslide Inventories Using Lidar Change Detection: Rethinking Landslide Activity in Big Storms

Session: Landslide Inventory Mapping and Next Steps: Assessing Susceptibility, Hazard Models, Risk, and Policy

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Abstract:

Between July 25 and July 30, 2022, a series of convective storms produced approximately 350 to 400 mm of rainfall across parts of eastern Kentucky, bringing catastrophic flash flooding and triggering landslides and debris flows. To understand the impact of the storms and get a better picture of the landslide hazard, we mapped landslides using lidar change detection (LCD) maps in approximately 1/3 of the impacted region and compared the result to a pre-storm historical landslide inventory. The LCD maps were generated from lidar collected by the Commonwealth of Kentucky in 2017 and 2023, before and after the storm event.

We produced an event inventory documenting nearly 6,500 landslides that were active between the two lidar acquisitions and compared that with a historical inventory >3,000 landslides that occurred prior to the 2017 lidar acquisition. LCD allows mappers to focus directly on changed areas, significantly reducing the exhaustive manual inspection required to visually compare two vintages of lidar. We described the event inventory (including landslide type and anthropogenic influence), evaluated differences in landslide frequency and area, and analyzed reactivation patterns and rate of historical landslides, which was approximately 20%. Projecting the results across the entire storm area suggests that the event triggered considerably more landslides than previously estimated, and prior analyses may have underestimated the number of the mass movements by an order of magnitude. Our results have critical implications for understanding single landslide events in eastern North America and supporting hazard assessment, event response, and long-term mitigation.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7884

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