Investigating the Subsurface at High Resolution Using Dark Fiber Distributed Acoustic Sensing (DAS)
Verónica Rodríguez Tribaldos
Lawrence Berkeley National Laboratory
- Date & Time
- Location
- Microsoft Teams
- Host
- Jeff McGuire
- Summary
In recent years, there has been growing interest in the seismological community for regional characterization and monitoring of subsurface processes at high temporal and spatial resolution, for applications as varied as fault identification, near-surface characterization or hydrological process monitoring. However, it has become evident that the utilization of permanent local or regional seismic networks for these purposes is limited, mostly due to sensor sparsity. The cost of running large-N, long-term temporary experiments is almost prohibitive. Distributed Acoustic Sensing (DAS) re-purposes telecommunication optical fibers as dense arrays of seismic sensors. This developing technology enables recording ground motions for long periods of time across long distances (10’s of km) at high spatial (~1 m) and temporal resolution at frequencies ranging from the mHz to the kHz. Recently, the deployment of this novel sensing technique on existing, unused fiber-optic cable networks, known as dark fiber, has offered an attractive alternative to classical seismological studies, as it facilitates acquisition of high-resolution data at regional scale. However, some challenges still exist before we can fully exploit the capabilities of this technology, the main challenge being the large data volumes derived from these several km-long, high density arrays. In this talk, we will show some examples of using dark fiber DAS for basin-scale characterization and monitoring using ambient seismic noise at a variety of scales in the Sacramento Valley, CA, and present preliminary observations from an ongoing experiment aiming at characterizing geothermal systems in the Imperial Valley, CA. We will also discuss some of the challenges associated with regional, high-resolution characterization using this novel technology and our recent attempts at developing effective data management and processing strategies.
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