Landslide Susceptibility and Runout Results for Chuuk, Federated States of Micronesia

Landslide hazards pose a serious threat to people and infrastructure across the Federated States of Micronesia (FSM). To support hazard assessment and mitigation efforts, the USGS Landslide Disaster Assistance Team (LDAT) produced a landslide susceptibility and runout map for Chuuk State using a digital elevation model (DEM) and Grfin Tools modeling (Cronkite-Ratcliff and others, 2025; Reid and others, 2025a).

This dataset includes the input digital elevation model (DEM) (Chuuk_DEM.tif) and Grfin Tools settings file (Chuuk_settings.yaml).  The DEM was created by merging, reprojecting, and clipping existing elevation data (U. S. Geological Survey, 2013a, 2013b). The settings file provides input parameters used for Grfin Tools, with parameter selection described in detail by Reid and others (in prep).

Primary outputs from Grfin Tools include:

landslide source zones (Chuuk_DEM_sourcearea.tif),
H/L reach angle (Chuuk_DEM_hlreachangle.tif),
debris-flow inundation extents (Chuuk_DEM_inundation.tif),
stream channels used for debris-flow routing (Chuuk_DEM_stream.shp)

Additional output files are produced by Grfin Tools and can be recreated with the provided DEM and settings files. This data release provides the three primary components of a landslide susceptibility map as raster files. The rasters are combined into a summary raster (Chuuk_susceptibility_map.tif) that is also provided as a KMZ file (Chuuk_susceptibility_map.kmz).

The Grfin Tools result files map areas susceptible to potential landslides or debris flows and are not predictions of specific events. For the given parameters, results show maximum potential extents based on empirical models and should not be interpreted as forecasts or likelihoods without further analysis.
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References:

Cronkite-Ratcliff, C., Reid, M.E., Brien, D.L., and Perkins, J.P., 2025, Grfin Tools - Software package and runtime documentation for users, version 1.0: U.S. Geological Survey Software Release, https://doi.org/10.5066/P9NVKFE2.

Reid, M.E., Brien. D.L., Cronkite-Ratcliff, C., and Perkins, J.P., (2025), Grfin Tools – User guide and methods for modeling landslide runout and debris-flow growth and inundation: U.S. Geological Survey Techniques and Methods, book 14, chap. A3, https://doi.org/10.3133/tm14A3.

Reid, M.E., Cerovski-Darriau, C., Brien, D.L., Leb, I.H., and Cyr, A.J., (in prep) From start to stop: Simple methods for mapping susceptibility to landslide runout and debris-flow inundation

U.S. Geological Survey, 2013, 3D Elevation Program 1/3-Arc-Second Digital Elevation Model: USGS 1/3 arc-second n08e151 1 x 1 degree DEM (published 2013), USGS 13 arc-second n08e151 1 x 1 degree - ScienceBase-Catalog

U.S. Geological Survey, 2013, 3D Elevation Program 1/3-Arc-Second Digital Elevation Model: USGS 1/3 arc-second n08e152 1 x 1 degree DEM (published 2013), USGS 13 arc-second n08e152 1 x 1 degree - ScienceBase-Catalog