Integrated Seismic Tomography and Magnetotelluric Inversion for High-Resolution Subsurface Imaging in Tectonically Active Regions

Project Abstract

We present a comprehensive study that integrates seismic tomography and magnetotelluric inversion to achieve high-resolution subsurface imaging in tectonically active regions, enabling improved characterization of fault zones, magma chambers, and fluid pathways. The research combines a dense, multi-parameter data fusion framework with advanced inversion algorithms and robust uncertainty quantification to produce coherent 3D models of velocity and electrical conductivity that reveal lithology, mineralogy, temperature, and fluid saturation contrasts at varying depths. We develop a joint inversion strategy that leverages complementary sensitivities seismic waves constrain mechanical properties and density, while magnetotelluric responses respond to electroneutral and fluid-related impedance contrasts, particularly in partially molten or fluid-rich zones. A novel coupling approach integrates structural priors from geological mapping and surface geophysical measurements with probabilistic Bayesian inference to mitigate non-uniqueness and depth leakage common to individual modalities. The methodology includes (i) preprocessing pipelines for seismic and MT datasets to ensure consistency in sampling, scale, and noise characterization, (ii) shear and P-wave velocity tomography complemented by anisotropy estimation to capture fracture networks and alignment, (iii) 2D and 3D MT impedance inversions with robust handling of galvanic distortion and regional strike variations, (iv) joint objective functions and hierarchical regularization that promote coherent interfaces between velocity and conductivity, and (v) a comprehensive uncertainty analysis via Markov Chain Monte Carlo and trans-dimensional inversion to quantify model plausibility and sensitivity to data errors. The study applies the framework to a high-resolution survey area within a tectonically active crust-mantle boundary, incorporating ambient noise, controlled-source seismic data, and MT measurements from dense station arrays. We assess model resolution using synthetic tests, checkerboard analyses, and recovery experiments that simulate realistic geologic complexity, followed by application to field data to delineate fault geometries, deep crustal anisotropy, fluid-bearing channels, and melt-rich zones. Outcome products include 3D joint velocity-conductivity volumes, cross-sections highlighting key structural features, and probabilistic maps of critical boundaries such as slip surfaces and melt transitions. The research aims to enhance predictive capabilities for seismic hazard assessment, mineral exploration, and geothermal exploration by providing a robust, integrated imaging toolset capable of revealing coupled thermo-chemical-geophysical processes in active tectonic settings. The project also evaluates computational efficiency and scalability, proposing parallelized inversion workflows and data compression strategies to enable real-time or near-real-time updates as new data become available.

Project Overview

What This Project Is About

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This project combines two geophysical methods—seismic tomography and magnetotellurics (MT)—to create detailed images of the Earth’s subsurface in tectonically active areas. Seismic tomography uses how seismic waves travel through rocks to map velocity variations, while MT uses natural electrical and magnetic fields to map how rocks conduct electricity. By putting these methods together, we aim to obtain higher-resolution, more reliable pictures of underground structures that influence earthquakes and volcanic activity.

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The Problem It Addresses

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Seismic data alone often has limited resolution, especially in complex regions. MT data can fill in electrical contrasts, like fluids and minerals, that seismic data might miss. However, each method has its own uncertainties. The project investigates how to integrate both datasets to reduce ambiguity, improve subsurface models, and better assess hazards such as fault zones and fluid pathways.

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Objectives of the Project

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1. Summarize the basic principles of seismic tomography and MT surveying in clear terms.
2. Develop a workflow to jointly invert seismic and MT data.
3. Test the workflow on synthetic datasets to evaluate performance.
4. Apply the method to a real tectonically active region with available data.
5. Assess how combining methods improves resolution and reliability.

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What You Will Do Step by Step

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1) Learn the basics of seismic waves and MT signals. 2) Gather publicly available seismic and MT datasets for a chosen study area. 3) Preprocess data (quality control, filtering, and alignment). 4) Build separate inversion models for seismic and MT data. 5) Develop a joint inversion approach to fuse results. 6) Validate with synthetic tests. 7) Interpret the final subsurface model in terms of geology and hazards. 8) Present findings and discuss limitations.

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Expected Outcome

A integrated subsurface model with improved resolution that highlights features related to faults, fluids, and mineral variation. The project should demonstrate that joint seismic-MT inversion provides more reliable hazard assessments and clearer guidance for field investigations.