Application of the Theory of Wave Propagation Through Random Media to Phase andAmplitude Fluctuations of Seismic P-Waves

摘要

Statistical descriptions of variations in seismic-wave velocity in the Earth arerelated to observations in phase, travel-time, and amplitude fluctuations of seismic-wave signals received at teleseismic and regional distances. Results were obtained by analysis of NORESS and NORSAR data, by stochastic tomography techniques and by numerical simulation. Combination of NORESS and NORSAR data has led to a more highly resolved Transverse Coherence Function of travel time, confirming the Flatte-Wu (FW) model of heterogeneities under NORSAR. Nonlinear inversion applied to NORSAR data has also verified the FW model parameters. Work to compare the FW stochastic model with deterministic heterogeneity models is in progress. Attempts to understand regional propagation by the same techniques have been unsuccessfully due to inability to identify high-frequency crustal propagation paths for regional ranges. Numerical simulation of fluctuations from a point source have verified models of turbulence (applied to the atmosphere). Teleseism, Heterogeneities, Random media, P-waves, NORSAR.