Abstract
Mapping fluid accumulation in the crust is pertinent for numerous applications including volcanic hazard assessment, geothermal energy generation, and mineral exploration. Here, we use seismic attenuation tomography to map the distribution of fluids in the crust below Uturuncu volcano, Bolivia. Seismic P wave and S wave attenuation, as well as their ratio (QP/QS), constrain where the crust is partially and fully fluid-saturated. Seismic anisotropy observations further constrain the mechanism by which the fluids accumulate, predominantly along aligned faults and fractures in this case. Furthermore, subsurface pressure-temperature profiles and conductivity data allow us to identify the most likely fluid composition. We identify shallow regions of both dry and H2O/brine-saturated crust, as well as a deeper supercritical H2O/brine column directly beneath Uturuncu. Our observations provide a greater understanding of Uturuncu's transcrustal hydrothermal system, and act as an example of how such methods could be applied to map crustal fluid pathways and hydrothermal/geothermal systems elsewhere.
| Original language | English |
|---|---|
| Article number | e2022GL100974 |
| Pages (from-to) | 1-12 |
| Journal | Geophysical Research Letters |
| Volume | 50 |
| Issue number | 5 |
| Early online date | 28 Feb 2023 |
| DOIs | |
| Publication status | Published - 16 Mar 2023 |
Bibliographical note
Funding Information:The authors thank all the PLUTONS team for fruitful discussions. The authors especially thank Ying Liu for providing the seismic velocity model that was used to locate the seismicity in this study and Martyn Unsworth for insightful conversations regarding the magnetotelluric data. The authors also thank the reviewers for their suggestions that improved the manuscript. The seismic data analyzed in this study is publicly available from IRIS, with the earthquake catalog used described in Hudson et al. (2022). The software used to measure path-average attenuation for each earthquake is SeisSrcMoment (Hudson, 2020), available open source. The shear-wave splitting analysis was undertaken using SWSPy (Hudson, 2022), another open source package. Some of the figures were produced using Generic Mapping Tools (GMT) (Wessel et al., 2019). Much of the seismic data analysis was performed using ObsPy (Beyreuther et al., 2010). This work and T.S.H. were funded by the NSFGEO-NERC Grant NE/S008845/1. J.D.B. thanks the Royal Society for financial support through a Research Professorship (RP\R1\201048). M.E.P. was funded by National Science Foundation Grant EAR-1757495. S.S.W. was funded by US National Science Foundation Grant EAR-2042553. The seismic data collection funded by the U.S. National Science Foundation Grants 0908281 and 0909254, and the UK Natural Environment Research Council Grant NE/G01843X/1.
Funding Information:
The authors thank all the PLUTONS team for fruitful discussions. The authors especially thank Ying Liu for providing the seismic velocity model that was used to locate the seismicity in this study and Martyn Unsworth for insightful conversations regarding the magnetotelluric data. The authors also thank the reviewers for their suggestions that improved the manuscript. The seismic data analyzed in this study is publicly available from IRIS, with the earthquake catalog used described in Hudson et al. ( 2022 ). The software used to measure path‐average attenuation for each earthquake is SeisSrcMoment (Hudson, 2020 ), available open source. The shear‐wave splitting analysis was undertaken using SWSPy (Hudson, 2022 ), another open source package. Some of the figures were produced using Generic Mapping Tools (GMT) (Wessel et al., 2019 ). Much of the seismic data analysis was performed using ObsPy (Beyreuther et al., 2010 ). This work and T.S.H. were funded by the NSFGEO‐NERC Grant NE/S008845/1. J.D.B. thanks the Royal Society for financial support through a Research Professorship (RP\R1\201048). M.E.P. was funded by National Science Foundation Grant EAR‐1757495. S.S.W. was funded by US National Science Foundation Grant EAR‐2042553. The seismic data collection funded by the U.S. National Science Foundation Grants 0908281 and 0909254, and the UK Natural Environment Research Council Grant NE/G01843X/1.
Publisher Copyright:
© 2023. The Authors.