Locating shallow seismic sources with waves scattered by surface topography: Validation of the method at the Nevada Test Site

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

Accurate and robust source location is fundamental in seismology. Previously, we proposed a new full waveform location method using waves scattered by topography near the source, and we demonstrated its potential in obtaining accurate source location using synthetic data. In the work presented here, we validate this method with observed seismic data from the 1993 Non-Proliferation Experiment, a chemical explosion with a precisely known location in a region with moderate topography at the Nevada Test Site. We select the first arrivals (Pn/Pg) and their immediate codas to determine the source location and compare our solution with the known location. We use a collocated-grid finite-difference method to calculate the strain Green’s tensor in a grid-search volume containing the source, and obtain three-component synthetic waveforms at 12 broadband seismic stations at regional distances using source-receiver reciprocity. We assess the solution using a least-squares misfit between the observed and synthetic waveforms. When scattered coda waves are incorporated, the best solution is within a few hundreds of meters of the exact source location, and the estimated uncertainty of the solution is reduced compared to the waveform based solution using only the P waves. The solution is robust to the choice of the frequency content and to the addition of random velocity heterogeneity. We conclude that the full waveform source location method is effective for real seismic data, though more validation tests like this one are needed to further understand its efficacy for source-station geometry, roughness of topography, signal quality and other factors.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Locating shallow seismic sources with waves scattered by surface topography: Validation of the method at the Nevada Test Site
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/2018JB017291
Volume 124
Issue 7
Year Published 2019
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Science Center
Description 12 p.
First page 7040
Last page 7051
Country United States
State Nevada