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DAS Derived Source Characterization of Ridgecrest Aftershocks Using Coda Spectral Ratios

Description: 

Distributed acoustic sensing technology provides a new capability to densely sample the seismic wavefield in difficult or previously inaccessible areas. However, measurements made on existing telecommunications cables are limited to uniaxial measurements of strain along the buried optical fiber, and the ground coupling of the cable is often unknown, hindering determination of seismic source properties. To overcome these limitations, we use coda spectral ratios to obtain estimates of the seismic source parameters using relative source spectra. Waveform envelope measurements of coda waves provide azimuthally insensitive information about their source spectra and ratios of envelopes from two sources measured by the same sensor can remove path, and crucially for DAS measurements, the sensor site effects. We demonstrate the effectiveness of this method using both DAS and traditional seismic measurements of the well-studied aftershocks of the 2019 Ridgecrest earthquake. We show that the relative source functions obtained using the DAS data are like those obtained using the traditional seismic data, confirming that the coda spectral ratio method can overcome the azimuthal and unknown ground coupling limitations of using DAS data for the study of seismic source properties. Further, we show that the derived stress drops and magnitudes are commensurate with those of other studies which employ more traditional seismic analysis methods.

Session: Understanding and Quantifying the Variability in Earthquake Source Parameter Measurements [Poster Session]

Type: Poster

Date: 5/3/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Brent

Student Presenter: No

Invited Presentation: 

Authors