Exploring the Potential for Joint Monitoring of Tectonic Tremor Using Dark Fiber and Seismometers
Description:
Tectonic tremor has been found among various plate boundary settings using observations from permanent seismic networks and/or temporary dense array deployments. Studying the behavior of tremor is important for understanding the physics behind a wide spectrum of fault slip behaviors, and for constraining the spatial extent and state of stress of a plate boundary’s seismogenic zone. Experiments in recent years have demonstrated that dark (unlit) fiber from telecommunication cables can be used for distributed acoustic sensing (DAS) to enhance our ability to monitor regular earthquakes. This new tool is especially valuable where seismometers are sparse, absent, or challenging to deploy and maintain long term. Fortunately, telecommunication fiber is spatially extensive across the Earth, especially onshore in (and between) urban environments that often reside near major active faults.
Here we extend the application of onshore DAS to the study of slow earthquakes as represented by non-volcanic tremor, to explore its potential for joint monitoring with seismometers. In April 2023 we conducted a small-aperture (4.5 km) DAS array experiment using dark fiber during an episodic tremor and slip event in Northern Cascadia (Port Angeles, WA). Using the PNSN tremor catalog for reference, we find that the array detected tremor signals generated down-dip of the seismogenic zone (>35 km depth), and validate these observations with the timing and shape of similar signals from nearby seismometers. Next, to evaluate the efficacy of DAS for tremor location, we perform a comparative analysis of epicenter estimates derived from traditional methods using seismometer only data and from seismometer plus DAS data. Given the large number of sampling points when using just one cable of fiber, the hope is that DAS has the ability to leverage seismometers with additional spatial resolution and constraints during heightened tremor activity. At a broader scope, we aim to demonstrate how these two instruments may be used harmoniously for enhanced monitoring of regular and slow earthquakes, and general seismological investigations.
Session: Advancing Seismology with Distributed Fiber Optic Sensing [Poster Session]
Type: Poster
Date: 5/3/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Manuel
Student Presenter: No
Invited Presentation:
Authors
Manuel Mendoza Presenting Author Corresponding Author manuel.mendoza@colorado.edu University of Colorado Boulder |
Eileen Martin eileenrmartin@mines.edu Colorado School of Mines |
Abdul Issah aissah@mines.edu Colorado School of Mines |
Ge Jin gjin@mines.edu Colorado School of Mines |
Veronica Gaete velgueta@uw.edu University of Washington |
Brad Lipovsky bpl7@uw.edu University of Washington |
Paul Bodin bodin@uw.edu University of Washington |
Stephen Malone smalone@uw.edu University of Washington |
Kenneth Creager kcc@uw.edu University of Washington |
Anne F Sheehan anne.sheehan@colorado.edu University of Colorado Boulder, Boulder, Washington, United States |
Exploring the Potential for Joint Monitoring of Tectonic Tremor Using Dark Fiber and Seismometers
Category
Advancing Seismology with Distributed Fiber Optic Sensing