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Seismic Event Location Using Levenberg-Marquardt Least Squares Inversion

Ballard, Sanford B.

The most widely used algorithm for estimating seismic event hypocenters and origin times is iterative linear least squares inversion. In this paper we review the mathematical basis of the algorithm and discuss the major assumptions made during its derivation. We go on to explore the utility of using Levenberg-Marquardt damping to improve the performance of the algorithm in cases where some of these assumptions are violated. We also describe how location parameter uncertainties are calculated. A technique to estimate an initial seismic event location is described in an appendix.