Landslide Susceptibility and Runout Results for Pohnpei, 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 Pohnpei 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 (Pohnpei_DEM.tif) and Grfin Tools settings file (Pohnpei_settings.yaml).  The DEM was created by merging, reprojecting, and clipping existing elevation data (U. S. Geological Survey, 2013a, 2013b) and the settings file provided input parameters for use with Grfin Tools. Parameter selection is described fully in Reid and others (2025b).

Primary outputs from Grfin Tools include:

landslide source zones (Pohnpei_DEM_sourcearea.tif),
H/L reach angle (Pohnpei_DEM_hlreachangle.tif),
debris-flow inundation extents (Pohnpei_DEM_inundation.tif),
stream channels used for debris-flow routing (Pohnpei_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 (Pohnpei_susceptibility_map.tif) and a KMZ file (Pohnpei_susceptibility_map.kmz).

The Grfin Tools results map areas susceptible to potential landslide or debris flow, 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 n07e158 1 x 1 degree DEM (published 2013), USGS 13 arc-second n07e158 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 n08e158 1 x 1 degree DEM (published 2013), USGS 13 arc-second n08e158 1 x 1 degree - ScienceBase-Catalog