A method of body‐wave waveform inversion for the determination of earth structure

Abstract

An iterative inversion method has been developed for the determination of velocity—depth structure using the waveforms of far‐field body‐wave seismograms. The inversion is accomplished by minimizing an error function that expresses the difference between data and synthetic seismograms. This error function is constructed to be insensitive to absolute amplitude and travel‐times, and is thus a measure of waveform error only. The Modified First Motion method of Mellman & Helmberger is used to express changes in the error function in terms of changes in the model parameters relative to some starting model. An approximate inverse is derived, which determines model perturbations that minimize the error function. Stability is provided through the inclusion of specific non‐linear terms in the inverse. As an example of the application of this method, the fine structure of the crust‐mantle transition is examined, using data from a Bering Sea refraction profile. Copyright © 1980, Wiley Blackwell. All rights reserved