DEPENDENCE OF THE APPARENT SEISMIC QUALITY FACTOR ON EPICENTRAL DISTANCE - AN INTERPRETATION IN TERMS OF FRACTAL STRUCTURE OF THE SEISMIC MEDIUM

Following Sato (1988a, b, Pageoph, 128:43-47) we evaluated an explicit formulation of the scattered energy in the single scattering approxim ation for a fractal distribution of scatterers in the lithosphere. We find that by using this hypothesis it is possible to explain the widel y observed lapse time dependence of Q-coda and the distance dependence of the measured direct-wave Q. On the basis of this approach we can e stimate the fractal dimension of the scatterers distribution by means of a simple fit of the experimental curves Q-coda versus lapse time (o r distance). We estimated the fractal dimension of the scatterer distr ibution for a number of regions of Italy and New Mexico, finding that it is in the range 2-3 for all of the regions.