DOI: 10.5066/p9as1ikb
title: Hypothetical landslide failure extents for hazard assessment, Barry Arm, western Prince William Sound, Alaska

description: This data release contains extent shapefiles for 16 hypothetical slope failure scenarios for a landslide complex at Barry Arm, western Prince William Sound, Alaska. The landslide is likely active due to debuttressing from the retreat of Barry Glacier (Dai and others, 2020) and sits above Barry Arm, posing a tsunami risk in the event of slope failure (Barnhart and others, 2021). Since discovery of the landslide by a citizen scientist in 2020, kinematic structural elements have been mapped (Coe and others, 2020) and ground-based and satellite synthetic aperture radar (SAR) have been used to track ongoing movement at a high spatial resolution (Schaefer and others, 2020; Schaefer and others, 2022). These efforts have revealed complex, zonal movement; the mechanisms of which remain unknown. To support hazard assessment, we constructed 16 different failure scenarios. The scenarios are all based on structural elements and/or remotely sensed evidence of motion but are also intended to cover a range of shapes and volumes of material such that different modes of failure and subsequent tsunami wave behavior can be modeled. Extents are presented in ESRI shapefile (.shp) format. Each shapefile has a Slip Angle field and a Sequence field. The Slip Angle field records the horizontal direction of failure (0 degrees = north). In some cases, a multi-phase failure is delineated, e.g., where the failure of part of the landslide might destabilize an additional upslope component. In these instances, an ordinal sequence of failure is specified in the Sequence field. These extents were manually digitized on lidar (1-meter horizontal resolution; Daanen and others, 2021) and SAR imagery (2&ndash;3-meter horizontal resolution; Schaefer and others, 2020; Schaefer and others, 2022) to align with either mapped kinematic components of the landslide or clear edges of motion identified by coherent synthetic aperture radar signals. As such they are subjective, based on expert opinion and current best available data.

References Cited
 
Barnhart, K.R., Jones, R.P., George, D.L., Coe, J.A., and Staley, D.M., 2021, Preliminary assessment of the wave generating potential from landslides at Barry Arm, Prince William Sound, Alaska: U.S. Geological Survey Open-File Report 2021&ndash;1071, 28 p., https://doi.org/10.3133/ ofr20211071.
 
Coe, J.A., Wolken, G.J., Daanen, R.P., and Schmitt, R.G., 2021, Map of landslide structures and kinematic elements at Barry Arm, Alaska in the summer of 2020: U.S. Geological Survey data release, https://doi.org/10.5066/P9EUCGJQ.
 
Daanen, R.P., Wolken, G.J., Wikstrom Jones, Katreen, and Herbst, A.M., 2021, Lidar-derived elevation data for upper Barry Arm, Southcentral Alaska, June 26, 2020: Alaska Division of Geological & Geophysical Surveys Raw Data File 2021-1, 9 p. https://doi.org/10.14509/30589.
 
Dai, C., Higman, B., Lynett, P.J., Jacquemart, M., Howat, I.M., Liljedahl, A.K., Dufresne, A., Freymueller, J.T., Geertsema, M., Ward Jones, M. and Haeussler, P.J., 2020, Detection and assessment of a large and potentially‐tsunamigenic periglacial landslide in Barry Arm, Alaska: Geophysical Research Letters, 47(22), e2020GL089800. https://doi.org/10.1029/2020GL089800.
 
Schaefer, L.N., Coe, J.A., Godt, J.W., and Wolken, G.J., 2020, Interferometric synthetic aperture radar data from 2020 for landslides at Barry Arm Fjord, Alaska: U.S. Geological Survey data release, https://doi.org/10.5066/P9Z04LNK.
 
Schaefer, L.N., Coe, J.A., and Wolken, G.J., 2022, Interferometric synthetic aperture radar data from 2021 for landslides at Barry Arm Fjord, Alaska: U.S. Geological Survey data release, https://doi.org/10.5066/P9QJ8IO4.