Tsunami inundation map of False Pass, Alaska

Tsunami inundation map of False Pass, Alaska, Report of Investigation 2025-4, evaluates potential tsunami hazards for the community of False Pass, Alaska, by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquakes. We define an updated suite of earthquakes--including Tohoku-style megathrust ruptures and other sources in the western Alaska Peninsula region--to calculate vertical seafloor displacements and model resulting tsunami dynamics. A hypothetical earthquake with maximum slip distributed between depths of 10 and 20 km (6.2 and 12.4 mi) results in 'worst case' tsunami inundation in False Pass. If the tsunami arrives at high tide, the maximum predicted overland flow depths in the community can reach up to 10 m (32.8 ft), and the currents could be as strong as 15 m/sec (29 knots). Dangerous wave activity is expected to last for more than 12 hours. Results presented here are intended to provide guidance to local emergency management agencies for tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami damage. The complete report and digital data are available from the DGGS website: http://doi.org/10.14509/31682.