Please use this identifier to cite or link to this item:
Title: Acoustic full waveform inversion for 2-D ambient noise source imaging
Shekar, Bharath
Dept. of Earth and Climate Science
Keywords: Seismic noise
Seismic interferometry
waveform inversion
Inverse theory
Issue Date: Apr-2023
Publisher: Oxford University Press
Citation: Geophysical Journal International, 234(3), 1628–1639.
Abstract: We present a method for estimating seismic ambient noise sources by acoustic full waveform inversion of interstation cross-correlations. The method is valid at local scales for laterally heterogeneous media, and ambient noise sources confined to the Earth’s surface. Synthetic tests performed using an actual field array geometry, are used to illustrate three unique aspects of our work. First: the method is able to recover noise sources of arbitrary spatial distribution, both within and outside the receiver array, with high fidelity. This holds true for complex velocity models and does not require a good initial guess for inversion, thereby addressing an outstanding issue in the existing research literature. Second: we analyse the extent of biases in source inversion that arise due to inaccurate velocity models. Our findings indicate that source inversion using simplified (e.g. homogeneous) velocity models may work reliably when lateral variations in velocity structure are limited to 5 or 10% in magnitude, but is vitiated by strong variations of 20% or higher, wherein the effect of strong scattering and/or phase distortions become significant. Finally, our technique is implemented without the adjoint method, which is usually inextricably linked to full waveform inversion. Inversions are performed using source kernels computed for each receiver pair, and this approach is computationally tractable for real-world problems with small aperture seismic arrays.
ISSN: 1365-246X
Appears in Collections:JOURNAL ARTICLES

Files in This Item:
There are no files associated with this item.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.