Three-dimensional shear wave velocity maps.
Three-dimensional shear wave velocity maps for the East Irish Sea, central United Kingdom as constructed using 3 separate tomographic inversion formalisms: a) Automatic Differential Variance Inference, b) Normalizing Flows, and c) Stein Variational Gradient Descent. These models are used to address the question “What is the area of the East Irish Sea basins within the top 200 meters of the seafloor?”. The solid line defines a mask delineating the region of consideration based on a priori information on the maximum outer limits of the basin, whereas black stars and red crosses define the thresholds used to discriminate low from high velocities with minimal bias. The estimate of the Irish Sea basin area derived through interrogation theory lies within 10 percent of that based on a shallow subsurface geological survey. Credit: Zhao et al. [2022], Figure 11a-c
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Solid Earth

Tomographic studies typically employ a single forward/inverse modelling formalism to derive models of subsurface properties. Various formalisms may involve different approximations and parameterizations leading to different biases. Moreover, many studies are motivated by “low-dimensional” questions that are addressed through human-biased interpretation of the “high-dimensional” and intrinsically biased model.

Zhao et al. [2022] demonstrate how multiple tomographic formalisms can be used simultaneously to remedy these deficiencies. They do so through an elegant probabilistic interrogation-theoretic framework applied to toy and real-world examples that validate their approach and serve as tutorials for tomographic practitioners.

Citation: Zhao, X., Curtis, A., & Zhang, X. (2022). Interrogating subsurface structures using probabilistic tomography: An example assessing the volume of Irish Sea basins. Journal of Geophysical Research: Solid Earth, 127, e2022JB024098.

—Michael Bostock, Editor, Journal of Geophysical Research: Solid Earth

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