MODAL FIELDS - A NEW METHOD FOR CHARACTERIZATION OF RANDOM SEISMIC VELOCITY HETEROGENEITY

Geologically and petrophysically constrained synthetic random velocity fields are important tools for exploring (through the application of numerical codes) the seismic response of small-scale lithospheric hete rogeneities. Statistical and geophysical analysis of mid- and lower-cr ustal exposures has demonstrated that the probability density function for some seismic velocity fields is likely to be discrete rather than continuous. We apply the term ''modal'' fields to describe fields of this sort. This letter details a methodology for generating synthetic modal fields which satisfy the von Karman covariance function. In addi tion, we explore some of the mathematics of ''modality'', and define a modality parameter which quantifies the variation between end members binary and continuous fields.