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Microearthquake Monitoring Using Dark Fiber and Distributed Acoustic Sensing (DAS)

Session: Fiber-Optic Seismology II [Poster]

Type: Poster

Date: 4/23/2021

Presentation Time: 03:45 PM Pacific

Description: 

We compare results from two experimental studies using distributed acoustic sensing (DAS) on dark fiber for microearthquake monitoring. Dark fiber consists of pre-existing fiber optic cables, installed as part of larger telecommunication networks, that are currently not in use. In this study, we refine seismic processing techniques to identify and map local microseismic events within the Sacramento Basin, CA and the Imperial Valley, CA. These two sites are tectonically quite different: relatively few seismic events occur within the Sacramento Basin, while the Imperial Valley has a number of active faults. Using these high-density passive seismic datasets, we investigate optimal pre-processing strategies and techniques to identify small natural tectonic events while excluding common anthropogenic seismic sources, such as cars driving along nearby highways.

Furthermore, we investigate the capability of the virtual seismometer method (VSM) on fiber datasets. VSM is an interferometric technique that allows us to measure the Green’s function between seismic sources. It is very sensitive to the individual source parameters and to the earth structure in the source region. The aim of this project is to help transform this type of data collection and processing techniques into products useful for basin-scale geothermal system characterization and subsurface mapping.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-818120

Presenting Author: Dennise Templeton

Student Presenter: No

Authors