| Popis: |
Potential tsunami hazard for the Umnak Island community of Nikolski is evaluated by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources. Worst-case hypothetical scenarios are defined by analyzing results of a sensitivity study of the tsunami dynamics related to various slip distributions along the Aleutian megathrust. The worst-case scenarios for Nikolski are thought to be thrust earthquakes in the Umnak Island region with their greatest slip at 10-30 km (6.2-19 mi) depth. We also consider Tohoku-type ruptures and an outer-rise rupture in the area of Umnak Island. The maximum predicted water depth on Main Street is about 15 m (49 ft), while the maximum current velocity in Mueller Cove could exceed 8 m/s (15 kt) and significant wave action could continue for at least 8 hours after the earthquake. 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. |
