- journal_title：Bulletin of the Seismological Society of America
- Contributor：Deborah Elaine Smith ; Brad T. Aagaard ; Thomas H. Heaton
- Publisher：Seismological Society of America
- Date：2005-
- Format：text/html
- Language：en
- Identifier：10.1785/0120030171
- journal_abbrev：Bulletin of the Seismological Society of America
- issn：0037-1106
- volume：95
- issue：3
- firstpage：800
- section：Articles
We investigate whether a shallow-dipping thrust fault is prone to wave-slip interactions via surface-reflected waves affecting the dynamic slip. If so, can these interactions create faults that are opaque to radiated energy? Furthermore, in this case of a shallow-dipping thrust fault, can incorrectly assuming a transparent fault while using dislocation theory lead to underestimates of seismic moment?
Slip time histories are generated in three-dimensional dynamic rupture simulations while allowing for varying degrees of wave-slip interaction controlled by fault-friction models. Based on the slip time histories, P and SH seismograms are calculated for stations at teleseismic distances. The overburdening pressure caused by gravity eliminates mode I opening except at the tip of the fault near the surface; hence, mode I opening has no effect on the teleseismic signal. Normalizing by a Haskell-like traditional kinematic rupture, we find teleseismic peak-to-peak displacement amplitudes are approximately 1.0 for both P and SH waves, except for the unrealistic case of zero sliding friction. Zero sliding friction has peak-to-peak amplitudes of 1.6 for P and 2.0 for SH waves; the fault slip oscillates about its equilibrium value, resulting in a large nonzero (0.08 Hz) spectral peak not seen in other ruptures. These results indicate wave-slip interactions associated with surface-reflected phases in real earthquakes should have little to no effect on teleseismic motions. Thus, Haskell-like kinematic dislocation theory (transparent fault conditions) can be safely used to simulate teleseismic waveforms in the Earth.