Subsurface Imaging of Distributed Acoustic Sensing Data Using a Dark Fiber Line in Reno, Nevada
Application of Distributed Acoustic Sensing (DAS) strain rate measurements of the ambient noise data has recently been studied in various areas of seismic imaging at the local and global scales. DAS measurement using a dark fiber line is particularly of interest due to the vast existing infrastructure of fiber optic networks used for telecommunication. In theory, the entire fiber-optic network may be used as a seismic acquisition instrument to measure broadband ground motion, allowing imaging of the underlying site conditions in places that would otherwise be too costly or impossible to perform with nodal seismic acquisition systems. One of the challenges faced in the imaging of the underlying site conditions using a dark fiber line in urban environments is the high level of anthropogenic noise sources and its proximity to the fiber line. The materials used in burying the fiber optic cable and its coupling with the surrounding soil can vary from one location to another due to its original application as a telecommunication instrument. These conditions add additional uncertainties in the usefulness of dark fiber DAS data in subsurface imaging of urban environments, which requires further analyses. The purpose of the current study is to analyze the usefulness of the obtained strain rate measurements using the dark fiber line in acquiring the dispersion curve and its inversion. The results show a good recovery of the dispersion curve fundamental mode from the noise correlation function acquired from DAS measurements. Performing a global 1D inversion of the acquired dispersion curve reveals variations in the layering structure of the underlying soil material. The inversion of the obtained dispersion curve can be used in improving understanding of the ground motion due to earthquakes in urban environments or be used as an initial model for more detailed imaging of the subsurface using a full waveform inversion method.
Session: Fiber Optic Seismology: Understanding Earth Structure and Dynamics with Distributed Sensors II
Type: Oral
Room: Cedar
Date: 4/21/2022
Presentation Time: 02:30 PM Pacific
Presenting Author: Majid Mirzanejad
Student Presenter: No
Additional Authors
Majid Mirzanejad Presenting Author mmirzanejad@unr.edu University of Nevada Reno |
Elnaz Seylabi Corresponding Author elnaze@unr.edu University of Nevada, Reno |
Scott Tyler styler@unr.edu University of Nevada Reno |
Rachel Hatch rhatch@unr.edu University of Nevada Reno |
Seth Saltiel ssaltiel@unr.edu University of Nevada Reno |
Jonathan Ajo-Franklin ja62@rice.edu Rice University |
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Subsurface Imaging of Distributed Acoustic Sensing Data Using a Dark Fiber Line in Reno, Nevada
Category
Fiber Optic Seismology: Understanding Earth Structure and Dynamics with Distributed Sensors
Description