On the full-waveform inversion of seismic moment tensors

TL;DR

This paper introduces a frequency-domain full-waveform inversion method for accurately locating and characterizing multiple seismic events simultaneously, even with limited or imperfect data, applicable in 2D and extendable to 3D.

Contribution

It presents a novel grid search-based joint source location and moment tensor inversion framework for seismic events, accommodating multiple sources and practical measurement challenges.

Findings

Effective reconstruction of multiple seismic events.

Robust performance with sparse and off-grid data.

Framework extendable to 3D seismic source problems.

Abstract

In this work, we propose a full-waveform technique for the spatial reconstruction and characterization of (micro-) seismic events via joint source location and moment tensor inversion. The approach is formulated in the frequency domain, and it allows for the simultaneous inversion of multiple point-like events. In the core of the proposed methodology is a grid search for the source locations that encapsulates the optimality condition on the respective moment tensors. The developments cater for compactly supported elastic bodies in $\mathbb{R}^2$; however our framework is directly extendable to inverse (seismic) source problems in $\mathbb{R}^3$ involving both bounded and unbounded elastic domains. A set of numerical results, targeting laboratory applications, is included to illustrate the performance of the inverse solution in situations involving: (i) reconstruction of multiple events, (ii) sparse (pointwise) boundary measurements, (iii) "off-grid" location of the micro-seismic events, and (iv) inexact knowledge of the medium's elastic properties.