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S/P amplitude ratios with Distributed Acoustic Sensing and application to earthquake focal mechanisms

Robert J. Skoumal·James William Atterholt·Andrew J. Barbour·Jeanne L. Hardebeck
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Abstract

Distributed acoustic sensing (DAS), which transforms a fiber optic cable into an array of high frequency strainmeters, has the potential to help us characterize earthquakes with a dense sampling of measurements. While earthquake focal mechanisms are frequently determined using P -wave polarities and S / P amplitude ratios with inertial seismometers, the dense sampling of DAS over potentially large portions of the focal sphere can aid our solutions. Here, we consider ∼200 regional earthquakes and thousands of S / P measurements on a DAS cable colocated with a network of inertial seismometers near Arcata, California. We demonstrate the S / P ratio measurements made on DAS are similar to those made on the inertial seismometers and can be used to constrain focal mechanism solutions.

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Geophysical Research LettersArticle

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Robert J. Skoumal, James William Atterholt, Andrew J. Barbour, Jeanne L. Hardebeck. 2025-10-15. S/P amplitude ratios with Distributed Acoustic Sensing and application to earthquake focal mechanisms. https://doi.org/10.1029/2025gl116373

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