Earthquake focal mechanisms with distributed acoustic sensing
Abstract Earthquake focal mechanisms provide critical in-situ insights about the subsurface faulting geometry and stress state. For frequent small earthquakes (magnitude< 3.5), their focal mechanisms are routinely determined using first-arrival polarities picked on the vertical component of seism...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2023-07-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-023-39639-3 |
| _version_ | 1827899778408644608 |
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| author | Jiaxuan Li Weiqiang Zhu Ettore Biondi Zhongwen Zhan |
| author_facet | Jiaxuan Li Weiqiang Zhu Ettore Biondi Zhongwen Zhan |
| author_sort | Jiaxuan Li |
| collection | DOAJ |
| description | Abstract Earthquake focal mechanisms provide critical in-situ insights about the subsurface faulting geometry and stress state. For frequent small earthquakes (magnitude< 3.5), their focal mechanisms are routinely determined using first-arrival polarities picked on the vertical component of seismometers. Nevertheless, their quality is usually limited by the azimuthal coverage of the local seismic network. The emerging distributed acoustic sensing (DAS) technology, which can convert pre-existing telecommunication cables into arrays of strain/strain-rate meters, can potentially fill the azimuthal gap and enhance constraints on the nodal plane orientation through its long sensing range and dense spatial sampling. However, determining first-arrival polarities on DAS is challenging due to its single-component sensing and low signal-to-noise ratio for direct body waves. Here, we present a data-driven method that measures P-wave polarities on a DAS array based on cross-correlations between earthquake pairs. We validate the inferred polarities using the regional network catalog on two DAS arrays, deployed in California and each comprising ~ 5000 channels. We demonstrate that a joint focal mechanism inversion combining conventional and DAS polarity picks improves the accuracy and reduces the uncertainty in the focal plane orientation. Our results highlight the significant potential of integrating DAS with conventional networks for investigating high-resolution earthquake source mechanisms. |
| first_indexed | 2024-03-12T23:22:15Z |
| format | Article |
| id | doaj.art-668ec99bd51141bb903e26e37ed3c506 |
| institution | Directory Open Access Journal |
| issn | 2041-1723 |
| language | English |
| last_indexed | 2024-03-12T23:22:15Z |
| publishDate | 2023-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Nature Communications |
| spelling | doaj.art-668ec99bd51141bb903e26e37ed3c5062023-07-16T11:21:43ZengNature PortfolioNature Communications2041-17232023-07-011411910.1038/s41467-023-39639-3Earthquake focal mechanisms with distributed acoustic sensingJiaxuan Li0Weiqiang Zhu1Ettore Biondi2Zhongwen Zhan3Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of TechnologySeismological Laboratory, Division of Geological and Planetary Sciences, California Institute of TechnologySeismological Laboratory, Division of Geological and Planetary Sciences, California Institute of TechnologySeismological Laboratory, Division of Geological and Planetary Sciences, California Institute of TechnologyAbstract Earthquake focal mechanisms provide critical in-situ insights about the subsurface faulting geometry and stress state. For frequent small earthquakes (magnitude< 3.5), their focal mechanisms are routinely determined using first-arrival polarities picked on the vertical component of seismometers. Nevertheless, their quality is usually limited by the azimuthal coverage of the local seismic network. The emerging distributed acoustic sensing (DAS) technology, which can convert pre-existing telecommunication cables into arrays of strain/strain-rate meters, can potentially fill the azimuthal gap and enhance constraints on the nodal plane orientation through its long sensing range and dense spatial sampling. However, determining first-arrival polarities on DAS is challenging due to its single-component sensing and low signal-to-noise ratio for direct body waves. Here, we present a data-driven method that measures P-wave polarities on a DAS array based on cross-correlations between earthquake pairs. We validate the inferred polarities using the regional network catalog on two DAS arrays, deployed in California and each comprising ~ 5000 channels. We demonstrate that a joint focal mechanism inversion combining conventional and DAS polarity picks improves the accuracy and reduces the uncertainty in the focal plane orientation. Our results highlight the significant potential of integrating DAS with conventional networks for investigating high-resolution earthquake source mechanisms.https://doi.org/10.1038/s41467-023-39639-3 |
| spellingShingle | Jiaxuan Li Weiqiang Zhu Ettore Biondi Zhongwen Zhan Earthquake focal mechanisms with distributed acoustic sensing Nature Communications |
| title | Earthquake focal mechanisms with distributed acoustic sensing |
| title_full | Earthquake focal mechanisms with distributed acoustic sensing |
| title_fullStr | Earthquake focal mechanisms with distributed acoustic sensing |
| title_full_unstemmed | Earthquake focal mechanisms with distributed acoustic sensing |
| title_short | Earthquake focal mechanisms with distributed acoustic sensing |
| title_sort | earthquake focal mechanisms with distributed acoustic sensing |
| url | https://doi.org/10.1038/s41467-023-39639-3 |
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