Stochastic Modeling of the November 30th M7.0 Anchorage Earthquake

Date: 4/26/2019

Time: 06:00 PM

Room: Grand Ballroom

The November 30th M7.0 earthquake near Anchorage, Alaska provided the strongest ground motions yet recorded on the Anchorage area strong motion network. These recordings allow for a comparison to be made between actual and synthetic time histories in a part of Alaska with frequent seismicity. Acceleration time histories were generated through stochastic finite source modeling for several strong motion stations in the Anchorage Bowl and the Fourier Amplitude Spectra was used to determine how well the models matched the recorded data. The earthquake rock motion was modeled using the finite source based stochastic modeling technique that is used in the EXSIM program developed by Boore and others. The finite fault method allows the fault to be divided into subfaults which are each modeled like a point source and are then summed in a time delayed fashion to account for rupture propagation. Parameters such as shear wave velocity were fixed based on literature and arrival time matching for the event and the fault parameters such as strike, dip, slip distribution, and hypocenter depth and location were fixed based on the CMT and USGS fault plane solutions. The soil column effects were taken into account through the use of site response relationships from previously recorded data in the Anchorage Bowl. Creating a stochastic model of this earthquake allows refinement of the parameters used for stochastic modeling in the Anchorage area, leading to the possibility of more accurate models of other, potentially more catastrophic, scenario earthquakes being generated.

Presenting Author: Stephanie K. Dow

Authors