Accession Number : ADP204461

Title :   Scattering Attenuation in Fractally Homogeneous Random Media,

Corporate Author : NEW MEXICO STATE UNIV LAS CRUCES DEPT OF PHYSICS

Personal Author(s) : Reese, C. ; Ni, J. ; Hearn, T.

PDF Url : ADP204461

Report Date : 14 AUG 1995

Pagination or Media Count : 9

Abstract : Much of seismic nuclear monitoring depends on a proper understanding of attenuation and scattering of regional seismic waves. This report seeks to characterize wave scattering from both an observational and theoretical approach. A theory of wave propagation in fractally homogeneous random media is developed and applied to southern Tibet in order to quantify the analytical and statistical properties of crust and upper lithosphere heterogeneity. Seismic velocity heterogeneity is modeled by a self-affine band limited random fractal. An approximation to multiple scattering theory yields a relationship between the exponent of the frequency dependent scattering quality factor Q and the fractal dimension of velocity iso-surfaces. In this study, the attenuation quality factor of P-waves, Qp, is calculated for southern Tibet and the implications for the fractal dimension of the velocity field are discussed. In addition, the topic of intermittent heterogeneity is introduced. The generalization of the model to fractally homogeneous media implies that scattering attenuation measurements are characterized by two fractal dimensions: one related to the self-affinity of the velocity field and the other related to the metric of the space which the field occupies. Within a fractal random media model, the attenuation calculation for southern Tibet yields a fractal dimension of velocity iso-surfaces of D = 9/4 which implies the existence of complex large-scale structure in the upper lithosphere.

Descriptors :   *SEISMIC DETECTION, *SEISMIC WAVES, *ARMS CONTROL, *NUCLEAR EXPLOSION DETECTION, *EARTHQUAKES, MATHEMATICAL MODELS, FRACTALS, SCATTERING, SYMPOSIA, VERIFICATION, MONITORING, UNDERGROUND EXPLOSIONS, NUCLEAR EXPLOSION TESTING, WAVE PROPAGATION, EARTH CRUST, ATTENUATION, HETEROGENEITY, SEISMIC DISCRIMINATION, TREATIES, SEISMIC VELOCITY, PRIMARY WAVES(SEISMIC WAVES), Q FACTOR, LITHOSPHERE.

Subject Categories : Government and Political Science
      Seismology
      Seismic Detection and Detectors
      Nuclear Weapons
      Geology, Geochemistry and Mineralogy

Distribution Statement : APPROVED FOR PUBLIC RELEASE