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Noise Interferometry With Spatial Gradients

Session: Fiber-Optic Seismology I [Poster]

Type: Poster

Date: 4/23/2021

Presentation Time: 11:30 AM Pacific

Description: 

In recent years, new seismic instruments including Distributed Acoustic Sensing (DAS) and rotation sensors are becoming more and more popular. Due to an increase in the availability of instruments and in public datasets, we need to incorporate those data types into our geophysical workflows.

For long continuous installations of sensors, noise interferometry is a well-established method to obtain subsurface information from passive recordings - resting on the assumption of Green’s Function retrieval by cross-correlation. We drop this assumption and derive a generalized formulation for seismic interferometry that can utilize not only displacement measurements, but also gradients thereof – such as velocity, strain and rotation.

This formulation enables us to model interferometric wavefields between arbitrary combinations of these observables. Based on these simulations, we can compute finite-frequency sensitivity kernels, indicating the sensitivity of the measurement – on arbitrary interferometric wavefields – to the subsurface structure as well as to the noise source distribution.

The developed framework accounts for potential source-structure tradeoff in environments where the noise source distribution is heterogeneous, and enables inversions utilizing correlations of combinations of different seismic observables, bringing us one step closer to multi-observational full waveform ambient noise inversion.

Presenting Author: Patrick Paitz

Student Presenter: No

Authors