Simulation of Teleseismic Body Waves, Regional Seismograms, and Rayleigh Wave Phase Shifts Using Two-Dimensional Nonlinear Models of Explosion Sources
- Steven R. Taylor,
- Howard J. Patton and
- Paul G. Richards
Published Online: 18 MAR 2013
Copyright 1991 by the American Geophysical Union.
Explosion Source Phenomenology
How to Cite
Stevens, J. L., Barker, T. G., Day, S. M., McLaughlin, K. L., Rimer, N. and Shkoller, B. (1991) Simulation of Teleseismic Body Waves, Regional Seismograms, and Rayleigh Wave Phase Shifts Using Two-Dimensional Nonlinear Models of Explosion Sources, in Explosion Source Phenomenology (eds S. R. Taylor, H. J. Patton and P. G. Richards), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM065p0239
- Published Online: 18 MAR 2013
- Published Print: 1 JAN 1991
Print ISBN: 9780875900315
Online ISBN: 9781118663820
- Underground nuclear explosions—Detection—Congresses;
Two-dimensional axisymmetric nonlinear simulations of underground nuclear explosions have been coupled to wave propagation codes to generate synthetic seismograms. The nonlinear models include plastic yielding, pore crushup, cracking, and shock weakening. The effects of gravity and the free surface interaction are explicitly included in the calculations. The calculations provide insight into the effects of spall, depth of burial, and tectonic strain release on seismic signals. A simple, physical model for spall is developed by comparing the complete two-dimensional waveform with the waveform generated by a one-dimensional explosion plus a shallow tension crack in the same layered medium. P-waves generated by the two-dimensional simulation are modeled very well by the simple tension crack plus explosion model, and the resulting parameters for the spall model are consistent with the limited set of near-field observations of spall. Spall is found to be a strong generator of the Lg phase. Comparison of two-dimensional calculations with tectonic prestress with linear models shows that the tectonic source has an effective radius of approximately 80 percent of the elastic radius of the explosion, and is large enough to induce Rayleigh wave reversals with realistic levels of prestress. Rayleigh wave phase shifts and apparent time delays are explained as an interference effect between the Rayleigh waves generated by the explosion and tectonic sources.