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Data Acquisition Protocol for Determining Embedded Sensitivity Functions
Published on: April 20, 2016
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Earthquake focal mechanisms with distributed acoustic sensing
Jiaxuan Li1, Weiqiang Zhu2, Ettore Biondi2
1Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA. jxli@caltech.edu.
Nature Communications
|July 13, 2023
Summary
This study introduces a new method to determine earthquake focal mechanisms using distributed acoustic sensing (DAS) data. Integrating DAS with traditional seismometers improves the accuracy of fault plane orientation for small earthquakes.
Area of Science:
- Geophysics
- Seismology
- Earthquake Science
Background:
- Earthquake focal mechanisms reveal subsurface faulting and stress.
- Traditional methods for small earthquakes (magnitude < 3.5) rely on seismometer polarities but suffer from limited azimuthal coverage.
- Distributed Acoustic Sensing (DAS) offers dense spatial sampling and long-range sensing, potentially improving azimuthal coverage.
Purpose of the Study:
- To develop and validate a data-driven method for measuring P-wave polarities from DAS data for earthquake focal mechanism inversion.
- To assess the effectiveness of integrating DAS-derived polarities with conventional seismic network data.
- To enhance the accuracy and reduce uncertainty in earthquake focal plane orientation.
Main Methods:
- A novel data-driven approach to measure P-wave polarities on DAS arrays using cross-correlations between earthquake pairs.
- Validation of inferred DAS polarities against regional seismic network catalogs.
- Joint focal mechanism inversion combining conventional seismic and DAS polarity data.
Main Results:
- Successfully inferred P-wave polarities from DAS data for two California deployments.
- Demonstrated that joint inversion of conventional and DAS polarities improves focal plane orientation accuracy.
- Showcased a reduction in uncertainty for focal plane orientation when incorporating DAS data.
Conclusions:
- The developed method effectively extracts P-wave polarities from DAS, overcoming challenges of single-component sensing and low signal-to-noise ratios.
- Integrating DAS with conventional seismic networks significantly enhances the resolution and reliability of earthquake focal mechanism studies.
- DAS technology holds substantial promise for advancing high-resolution earthquake source mechanism investigations.
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