An upper-crust lid over the Long Valley magma chamber
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1.
California Institute of Technology
Abstract
Geophysical characterization of calderas is fundamental in assessing their potential for future catastrophic volcanic eruptions. The mechanism behind the unrest of Long Valley Caldera in California remains highly debated, with recent periods of uplift and seismicity driven either by the release of aqueous fluids from the magma chamber or by the intrusion of magma into the upper crust. We use distributed acoustic sensing data recorded along a 100-kilometer fiber-optic cable traversing the caldera to image its subsurface structure. Our images highlight a definite separation between the shallow hydrothermal system and the large magma chamber located at ~12-kilometer depth. The combination of the geological evidence with our results shows how fluids exsolved through second boiling provide the source of the observed uplift and seismicity.
Copyright and License
© 2023 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).
Acknowledgement
We would like to thank OptaSense for the support provided for this calibration experiment. In particular, we thank M. Karrenbach, V. Yartsev, and V. Bogdanov. We authors also thank the California Broadband Cooperative for providing access to the Digital 395 telecommunication fibers. We would like to thank J. R. Ryan-Davis, R. W. Clayton, and J. M. Jackson for suggestions on the initial manuscript draft. Last, we thank C. Iovine for the technical help provided in producing Fig. 5. The tomography workflow is part of a provisional U.S. patent filed by the California Institute of Technology (CIT file no. CIT-9029-P).
Funding
This work was supported by the National Science Foundation (NSF) Faculty Early Career Development Program (CAREER), award number 1848166; Resnick Institute of Sustainability; and Gordon and Betty Moore Foundation.
Contributions
Conceptualization: E.B. and Z.Z. Methodology: E.B., W.Z., and J.L. Data collection and fieldwork: E.B. and E.F.W. Supervision: Z.Z. Writing—original draft: E.B. Writing—review and editing: E.B., Z.Z., W.Z., J.L., and E.W.
Data Availability
All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Seismic data at conventional stations are from the Northern California Earthquake Data Center (https://ncedc.org/) and the Nevada Seismic Network (www.seismo.unr.edu/). The DAS travel times of the used events and velocity models are available at the Zenodo repository: https://doi.org/10.5281/zenodo.8270895.
Conflict of Interest
The authors declare that they have no competing interests.
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Additional details
- DOI
- 10.1126/sciadv.adi9878
- PMCID
- PMC10584340
- National Science Foundation
- EAR-1848166
- Gordon and Betty Moore Foundation
- Caltech groups
- Division of Geological and Planetary Sciences, Seismological Laboratory, Resnick Sustainability Institute