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Main Authors: da Silva, A. A. M., Novotnty, A. A., Amad, A. A. S., Guzina, B. B.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2401.08677
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author da Silva, A. A. M.
Novotnty, A. A.
Amad, A. A. S.
Guzina, B. B.
author_facet da Silva, A. A. M.
Novotnty, A. A.
Amad, A. A. S.
Guzina, B. B.
contents Micro-seismic events, naturally occurring within geological formations and quasi-brittle engineered systems, provide a powerful window into the evolving processes of material degradation and failure. Accurate characterization of these events is critical for a comprehensive understanding of the underpinning fracturing mechanisms and potential implications. In this work, we present an algorithm for the spatial reconstruction and characterization of micro-seismic events in a three-dimensional bounded elastic body (with known geometry and material properties) via joint source location and moment tensor inversion. Assuming availability of the full-waveform ``acoustic emission'' traces whose spectral content can be exposed via Fourier transform, the inverse solution is based on (i) a time-harmonic (forward) elastodynamic model and (ii) the concept of topological derivative as a framework for robust event reconstruction. On exploiting an equivalence between the elastic wavefield generated by the creation of a new micro-surface and that stemming from a suitable set of dipoles and double-couples (whose strengths are synthesized via the seismic moment tensor), we formulate the inverse problem as that for the real (in-phase) and imaginary (out-of-phase) components of the moment tensor at trial grid locations. In this way the optimal solution is obtained via a combinatorial search over a prescribed grid, inherently allowing for successive refinements of event reconstruction over the region(s) of interest. The analysis is illustrated by numerical experiments highlighting the key features of the inversion scheme including the reconstruction of multiple events, localization of the ``off-grid'' micro-seismic events, and the ability to handle noisy data. The results in particular highlight the utility of multi-frequency event reconstruction toward reducing the demand on the number of sensing locations.
format Preprint
id arxiv_https___arxiv_org_abs_2401_08677
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Full-waveform reconstruction of micro-seismic events via topological derivative approach
da Silva, A. A. M.
Novotnty, A. A.
Amad, A. A. S.
Guzina, B. B.
Geophysics
Micro-seismic events, naturally occurring within geological formations and quasi-brittle engineered systems, provide a powerful window into the evolving processes of material degradation and failure. Accurate characterization of these events is critical for a comprehensive understanding of the underpinning fracturing mechanisms and potential implications. In this work, we present an algorithm for the spatial reconstruction and characterization of micro-seismic events in a three-dimensional bounded elastic body (with known geometry and material properties) via joint source location and moment tensor inversion. Assuming availability of the full-waveform ``acoustic emission'' traces whose spectral content can be exposed via Fourier transform, the inverse solution is based on (i) a time-harmonic (forward) elastodynamic model and (ii) the concept of topological derivative as a framework for robust event reconstruction. On exploiting an equivalence between the elastic wavefield generated by the creation of a new micro-surface and that stemming from a suitable set of dipoles and double-couples (whose strengths are synthesized via the seismic moment tensor), we formulate the inverse problem as that for the real (in-phase) and imaginary (out-of-phase) components of the moment tensor at trial grid locations. In this way the optimal solution is obtained via a combinatorial search over a prescribed grid, inherently allowing for successive refinements of event reconstruction over the region(s) of interest. The analysis is illustrated by numerical experiments highlighting the key features of the inversion scheme including the reconstruction of multiple events, localization of the ``off-grid'' micro-seismic events, and the ability to handle noisy data. The results in particular highlight the utility of multi-frequency event reconstruction toward reducing the demand on the number of sensing locations.
title Full-waveform reconstruction of micro-seismic events via topological derivative approach
topic Geophysics
url https://arxiv.org/abs/2401.08677