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WITHDRAWN Spatio-Temporal Fidelity of DAS Arrays to Compression Seismic Signals: Impacts on Real-Time Source Estimates

Description: 

WITHDRAWN DAS recordings of $P$ waves have traditionally been associated with the shear component of oblique arrivals resulting in axial phase shift along the cables. However, careful examination of the records created by 478 local events in Japan reveals modal perturbations along the cable resulting from normal incidence of both P and S waves. We model this phenomenon as large scale oscillations (typically over a few kilometers) of the cable under localized forces with the cable axial and torsional tensions as restoring agents. Based on our model, spatial and temporal frequencies of the oscillations are determined by cable properties, almost regardless of earthquake magnitude. This is while modal amplitudes are significantly affected by the velocity structure of the deployment site, as well as earthquake radiation pattern on second order. The modal property of these waves has significant implications in both detection and magnitude estimation of earthquakes and as such needs to be considered in hazard assessment and early warning in active subduction zones.

Session: Advancing Seismology with Distributed Fiber Optic Sensing - II

Type: Oral

Date: 5/3/2024

Presentation Time: 11:00 AM (local time)

Presenting Author: Amir

Student Presenter: No

Invited Presentation: 

Authors