Electronic Supplement to
Evidence for a Supershear Transient During the 2002 Denali Fault Earthquake

by Eric M. Dunham and Ralph J. Archuleta

MPEG Movies of the Rupture History and Ground Motion

An interesting sequence of strong ground motions from the 2002 Denali Fault, Alaska, earthquake was recorded 3km from the fault at the Alyeska Pipeline Service Company's pump station 10 (PS10). We present three spontaneous rupture models to explain the seismograms. Model I allows slip to 10km depth and uses a purely slip-weakening friction law without frictional healing. The synthetic fault parallel pulse width is too broad to match the records. The next models explore two alternative mechanisms that limit the pulse width. In model II, we add frictional healing with a 1.5s time scale, but continue to allow slip to 10km depth. In model III, we restrict slip to 5km depth, but do not include any frictional healing. Both mechanisms generate comparable waveforms.

The movies presented below demonstrate the connections between the slip history on the fault surface and the resulting ground motions.

Movies

Movie 1 (9.1MB MPEG file) Evolution of slip velocity on the fault surface and its relationship to ground motion at PS10 for model I (no healing, slip to 10km depth). The black trace denotes the particle velocities recorded at PS10 and the red trace shows the development of the synthetics.

Movie 2 (9.0MB MPEG file) Slip velocity history for model II (including healing, slip to 10km depth).

Movie 3 (10.2MB MPEG file) Slip velocity history for model III (no healing, slip to 5km depth).

Movie 4 (7.3MB MPEG file) Evolution of fault parallel ground motion on the free surface and its relationship to ground motion at PS10 for model I (no healing, slip to 10km depth). The black trace denotes the FP particle velocity recorded at PS10 and the red trace shows the development of the synthetics. PS10 is marked by the triangle. Although the FP motion is antisymmetric across the fault, it is plotted as symmetric for visualization purposes.

Movie 5 (7.3MB MPEG file) Fault parallel ground motion for model II (including healing, slip to 10km depth).

Movie 6 (7.9MB MPEG file) Fault parallel ground motion for model III (no healing, slip to 5km depth).

Movie 7 (7.5MB MPEG file) Evolution of fault normal ground motion on the free surface and its relationship to ground motion at PS10 for model I (no healing, slip to 10km depth). The black trace denotes the FN particle velocity recorded at PS10 and the red trace shows the development of the synthetics. PS10 is marked by the triangle.

Movie 8 (7.5MB MPEG file) Fault normal ground motion for model II (including healing, slip to 10km depth).

Movie 9 (8.3MB MPEG file) Fault normal ground motion for model III (no healing, slip to 5km depth).

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