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Focal Mechanism Inversion With Distributed Acoustic Sensing

Description: 

Focal mechanism inversion with distributed acoustic sensing (DAS) has been challenging due to its single-component sensing and low signal-to-noise ratios compared to conventional seismic instruments. However, DAS has several advantages that can be leveraged to improve the inversion accuracy and resolution. Firstly, the widespread deployment of telecommunication (dark) fibers allows for an improvement on the azimuthal coverage in current seismic networks. Secondly, the ultra-dense spatial sampling of DAS can tightly constrain the orientation of nodal planes using P-wave polarity reversals across channels. In this study, we propose a systematic method to convert the DAS array into an ultra-dense polarity discriminator for improving the accuracy of focal mechanism inversions. We test our method on two DAS arrays with 50-km sensing ranges and 10-meter channel spacing and verify the inverted P-wave polarities using catalog focal mechanisms. We show that a joint inversion using P-wave polarities determined from DAS and conventional seismic stations can improve the accuracy and decrease the uncertainty of inverted earthquake focal mechanisms.

Session: Understanding Earth Systems with Fiber-optic Cables [Poster]

Type: Poster

Date: 4/19/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Jiaxuan Li

Student Presenter: No

Invited Presentation: 

Authors