Q and structure

An acoustic energy flow through a heterogeneous medium is characterized by transfer equations involving both scattering and real loss coefficients. Different values of seismicQ may be obtained from measurements of different portions of a seismic record, indicating a separation of the effects on energy propagation of scattering and real loss parameters. In cases in which these parameters can be separated, they can then be used in seismic modeling. As an example, a model is presented in which scattering occurs to a depth of about 10 km below the volcanic ridge in the Tonga-Fiji region. The case of the lunar maria is discussed in terms of the relation of measured seismicQ, scattering parameters, and direct ray propagation parameters. The results indicate that a fairly simple jointed bedrock model is compatible with observed lunar seismic data.Publication No. 1037 of the Institute of Geophysics and Planetary Physics, University of California, Los Angeles 90024, U.S.A.