미국
Landslide hazard susceptibility mapping in Haines, Alaska
Landslide hazard susceptibility mapping in Haines, Alaska, Report of Investigation 2024-8, provides a map and database of historical and prehistoric slope failures, maps of shallow and deep-seated landslide susceptibility, and a map of simulated debris flow runouts for the city and borough of Haines, Alaska. This work was prompted by the deadly Beach Road landslide that occurred on December 2, 2020, in Haines, Alaska, which highlights the significant safety and financial risks posed by slope failures to people and infrastructure. To better inform the Haines Borough of their potential landslide hazards and increase the city's hazard resiliency, the Alaska Division of Geological & Geophysical Surveys (DGGS) developed maps of historical and prehistorical slope failures, shallow landslide susceptibility, and modeled debris flow runouts. DGGS staff created a shallow landslide susceptibility map following protocols like those developed by the Oregon Department of Geology and Mineral Industries, which includes incorporating landslide inventory data, geotechnical soil properties, and lidar-derived topographic slope to calculate the Factor of Safety (FOS), which serves as a proxy for landslide susceptibility. Debris flow runout extents were generated using the model Laharz, which simulates runout extents based on catchment-specific physical parameters (e.g., hypothetical sediment volumes). Data from these analyses are collectively intended to depict locations where landslides are relatively more likely to occur or are relatively more likely to travel. The results provide important hazard information that can help guide planning and future risk investigations. The maps are not intended to predict slope failures and are site-specific; detailed investigations should be conducted before development in vulnerable areas. Results are for informational purposes and are not intended for legal, engineering, or surveying uses. These data and the interpretive maps and report are available from the DGGS website: http://doi.org/10.14509/31309.