Scattering of teleseismic body waves along the Hayward-Calaveras fault system


Broadband, digital, teleseismic P-wave data from the University of California, Berkeley, stations BKS, MHC, and SAO are used to study the character of teleseismic P coda. Velocity heterogeneity in structure near these stations gives rise to a variety of scattering effects, which include azimuthly dependent receiver functions, large tangential component particle motions, and high levels of P coda. P codas for shallow and deep teleseisms are analyzed for three frequency bands centered at 1.5, 0.75 and 0.375 Hz. Observed coda decay rate and level are fit with an energy flux theory to parameterize scattering effects near the source and at the receiver. Coda decay rate and level for deep earthquakes are seen to be stable observables between stations, implying that the scattered coda field is homogeneously distributed over the receiver network validating a major assumption in the energy flux model. Scattering Q(Qs) is not particularly well constrained by the data and is inferred to be affected by focusing and defocusing effects of the direct P waves. -from Authors

Publication Title

Bulletin - Seismological Society of America

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