Estimating Focal Mechanism of Small Earthquakes Using S/P Amplitude Ratios of Distributed Acoustic Sensing Records

Abstract We proposed a method for estimating focal mechanisms based on S/P amplitude ratios from distributed acoustic sensing (DAS) records for single earthquakes and successfully obtained the mechanisms from four events. This method involves measuring the maximum amplitude ratio between the S‐ and...

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Main Authors: Y. Funabiki, M. Miyazawa
Format: Article
Language:English
Published: Wiley 2025-05-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2024GL113963
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author Y. Funabiki
M. Miyazawa
author_facet Y. Funabiki
M. Miyazawa
author_sort Y. Funabiki
collection DOAJ
description Abstract We proposed a method for estimating focal mechanisms based on S/P amplitude ratios from distributed acoustic sensing (DAS) records for single earthquakes and successfully obtained the mechanisms from four events. This method involves measuring the maximum amplitude ratio between the S‐ and P‐waves of the DAS records, followed by searching for the parameters of the focal mechanism. We applied this method to the DAS records of four shallow earthquakes from central Japan with magnitudes ranging from M2.2 to 3.4. The estimated mechanisms were consistent with the distribution of P‐wave polarities from conventional seismometers despite recording only one component along the cable. This straightforward approach may be effective because of the wave scattering caused by near‐surface heterogeneities and the varying orientations of the cable sections corresponding to the channels. Consequently, the observed scattered waves preserved the overall radiation patterns, allowing us to obtain the radiation patterns from a single‐component record.
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publishDate 2025-05-01
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series Geophysical Research Letters
spelling doaj-art-8d07affc6b5d44dd9cda0fc330dba20e2025-08-20T02:17:01ZengWileyGeophysical Research Letters0094-82761944-80072025-05-01529n/an/a10.1029/2024GL113963Estimating Focal Mechanism of Small Earthquakes Using S/P Amplitude Ratios of Distributed Acoustic Sensing RecordsY. Funabiki0M. Miyazawa1Graduate School of Science Kyoto University Kyoto JapanDisaster Prevention Research Institute Kyoto University Kyoto JapanAbstract We proposed a method for estimating focal mechanisms based on S/P amplitude ratios from distributed acoustic sensing (DAS) records for single earthquakes and successfully obtained the mechanisms from four events. This method involves measuring the maximum amplitude ratio between the S‐ and P‐waves of the DAS records, followed by searching for the parameters of the focal mechanism. We applied this method to the DAS records of four shallow earthquakes from central Japan with magnitudes ranging from M2.2 to 3.4. The estimated mechanisms were consistent with the distribution of P‐wave polarities from conventional seismometers despite recording only one component along the cable. This straightforward approach may be effective because of the wave scattering caused by near‐surface heterogeneities and the varying orientations of the cable sections corresponding to the channels. Consequently, the observed scattered waves preserved the overall radiation patterns, allowing us to obtain the radiation patterns from a single‐component record.https://doi.org/10.1029/2024GL113963DASfocal mechanism
spellingShingle Y. Funabiki
M. Miyazawa
Estimating Focal Mechanism of Small Earthquakes Using S/P Amplitude Ratios of Distributed Acoustic Sensing Records
Geophysical Research Letters
DAS
focal mechanism
title Estimating Focal Mechanism of Small Earthquakes Using S/P Amplitude Ratios of Distributed Acoustic Sensing Records
title_full Estimating Focal Mechanism of Small Earthquakes Using S/P Amplitude Ratios of Distributed Acoustic Sensing Records
title_fullStr Estimating Focal Mechanism of Small Earthquakes Using S/P Amplitude Ratios of Distributed Acoustic Sensing Records
title_full_unstemmed Estimating Focal Mechanism of Small Earthquakes Using S/P Amplitude Ratios of Distributed Acoustic Sensing Records
title_short Estimating Focal Mechanism of Small Earthquakes Using S/P Amplitude Ratios of Distributed Acoustic Sensing Records
title_sort estimating focal mechanism of small earthquakes using s p amplitude ratios of distributed acoustic sensing records
topic DAS
focal mechanism
url https://doi.org/10.1029/2024GL113963
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