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In this report we evaluate potential tsunami hazards for the southeastern Alaska communities of Skagway and Haines and numerically model the extent of inundation from tsunami waves generated by tectonic and submarine landslide sources. We calibrate our tsunami model by numerically simulating the 2011 Tohoku, Japan tsunami at Skagway and comparing our results to instrument records. Analysis of calculated and observed water level dynamics for the 2011 event in Skagway reveals that the model underestimates the observed wave heights in the city by a factor of 1.5, likely due to complex tsunami-tide interactions. We compensate for this underestimation numerically by increasing the coseismic slip of the hypothetical tsunami sources in our models. Potential hypothetical maximum credible tsunami sources include variations of the extended 1964 rupture and megathrust earthquakes in the Prince William Sound and Alaska Peninsula regions. Local underwater landslide events in Taiya, Chilkoot, and Chilkat inlets are also considered as possible tsunamigenic scenarios. The results show that the maximum predicted wave height resulting from a tectonic tsunami is 2-3 m (7-10 ft) in Skagway and Haines, while the maximum landslide-generated tsunami may cause a runup of 15-16 m (49-52 ft). Results presented here are intended to provide guidance to local emergency management agencies in tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards. Users can access the complete report and digital data from the DGGS website: http://doi.org/10.14509/30029. |