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ABSTRACT Distributed acoustic sensing (DAS) technology is an emerging field of seismic sensing that enables recording ambient noise seismic data along the entire length of a fiber-optic cable at meter-scale resolution. Such a dense spatial resolution of recordings over long distances has not been possible using traditional methods because of limited hardware resources and logistical concerns in an urban environment. The low spatial resolution of traditional passive seismic acquisition techniques has limited the accuracy of the previously generated velocity profiles in many important urban regions, including the Reno-area basin, to the top 100 m of the underlying subsurface. Applying the method of seismic interferometry to ambient noise strain rate data obtained from a dark-fiber cable allows for generating noise cross correlations, which can be used to infer shallow and deep subsurface properties and basin geometry. We gathered DAS ambient noise seismic data for this study using a 12 km portion of a dark-fiber line in Reno, Nevada. We used gathered data to generate and invert dispersion curves to estimate the near-surface shear-wave velocity structure. Comparing the generated velocity profiles with previous regional studies shows good agreement in determining the average depth to bedrock and velocity variations in the analyzed domain. A synthetic experiment is also performed to verify the proposed framework further and better understand the effect of the infrastructural cover along the cable. The results obtained from this research provide insight into the application of DAS using dark-fiber lines in subsurface characterization in urban environments. It also discusses the potential effects of the conduit that covers such permanent fiber installations on the produced inversion results.
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This content will become publicly available on June 17, 2026
Evaluating subsurface imaging performance with ocean-bottom distributed acoustic sensing and double beamforming
SUMMARY The high cost of active surveys and the scarcity of underwater instruments hinder the availability of seismic imaging in oceanic environments. Ocean-bottom Distributed Acoustic Sensing (OBDAS) utilizing existing telecommunicational infrastructure is an alternative and economical approach to illuminate the subsurface at unprecedented resolution and over distances of tens of kilometers. In this study, we utilize OBDAS data along a 60-km cable perpendicular to the coast of Oregon to image the continental shelf subsurface. We extract landward and seaward surface waves via cross-correlation and coherent stacking of the ambient seismic field. To stably measure dispersions of both the fundamental modes and higher overtones, we apply a double-beamforming (DBF) workflow across different array subsections in the 0.2–3 Hz band with a spatial averaging technique. We perform a perturbational-based inversion scheme to reliably invert for S-wave velocities over the first 2000 m of the subsurface underlying the fiber-optic cable. By comparing our results with the 1-D slant-stack approach, we demonstrate the applicability of the DBF method on the OBDAS data set and the enhanced spatial resolution of this approach. From our single-mode DBF results, we observe a coherent layering feature in the Florence shelf-sea region, while multimode DBF results reveal possibly smaller-scale heterogeneity in the study region.
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- Award ID(s):
- 2022716
- PAR ID:
- 10647223
- Publisher / Repository:
- OUP
- Date Published:
- Journal Name:
- Geophysical Journal International
- Volume:
- 242
- Issue:
- 2
- ISSN:
- 0956-540X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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