Nicolsky, D.J., Suleimani, E.N., Koehler, R.D., and Salisbury, J.B., 2019, Developing an approximate tsunami hazard zone for areas with poor topographic coverage in Alaska: Pure and Applied Geophysics, p. 1-21.
Tsunamigenic earthquakes along the Alaska?Aleutian megathrust pose a major threat to many rural coastal communities in Alaska. To mitigate the impact of tsunamis and minimize loss of life, maximum potential runup and tsunami hazard zones need to be estimated despite a lack of the high-resolution digital elevation models. In this manuscript we present a methodology to approximate tsunami hazard zones in areas with poor topographic and bathymetric coverage. To manage a trade-off between the computational complexity and lack of quality data, we develop three scenario earthquakes with the intention that one of them characterizes impacts of a credible worst-case event. We then apply a safety factor to account for the limited number of considered scenarios and a coarse resolution elevation model used to simulate water dynamics near the community. The developed methodology is illustrated using a case study focused on the community of Adak, in the Andreanof Islands, Alaska. To validate the proposed method, we explore sensitivity of tsunami height with respect to the coseismic slip distribution and develop a comprehensive set of credible worst-case scenarios for the community. The tsunami hazard zone, developed with the use of the safety factor, is validated against high-resolution modeling of potential inundation according to the set of worst-case scenarios in a number of other coastal communities.
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