UAF-GI professor Carl Tape's simulation of the M7.1 Iniskin Earthquake shows movement of the earthquake's seismic wavefield through a realistic 3D earth structure model. The wavefield is complex and irregular because the speed of the waves is affected by the kinds of materials they pass through.

Here, the deep sedimentary basin in Cook Inlet slows the waves considerably, causing them to close in on both sides and converge on Knik Arm and Matanuska. These softer materials also reverberate longer than harder rock does, resulting in longer and more intense ground shaking from the earthquake for people living on top of those sediments.

It's important to remember that this is a simulation based on modeling rather than on seismic waveform data from the earthquake itself. Still, it is compellingly similar to how people in Southcentral Alaska have described their experiences of the earthquake.

The simulation was performed on the high-performance computing cluster at the University of Alaska Fairbanks, Research Computing Systems. The 3D wave propagation code is called SPECFEM3D. Animations and full description can be found on Carl Tape's research page.

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