Joint Inversion in Hydrogeophysics and Near‐Surface Geophysics

Abstract

Key points:• Structural joint inversions of near-surface geophysical data are often favored • Time-lapse geophysical data are sensitive to hydrological state variables • Joint inversion in hydrogeophysics should include flow-and transport modeling This work is published, please cite as: Linde, N., and J. Doetsch, 2016, Joint inversion in hydrogeophysics and near-surface geophysics. in: Integrated imaging of the Earth, M. Moorkamp, P. Lelievre, N. Linde, and A. AbstractThe near-surface environment is often too complex to enable inference of hydrological and environmental variables using one geophysical data type alone. Joint inversion and coupled inverse modeling involving numerical flow-and transport simulators have, in the last decade, played important roles in pushing applications towards increasingly challenging targets. Joint inversion of geophysical data that is based on structural constraints is often favored over model coupling based on explicit petrophysical relationships. More specifically, cross-gradient joint inversion has been applied to a wide range of near-surface applications and geophysical data types. To infer hydrological subsurface properties, the most appropriate approach is often to use temporal changes in geophysical data that can be related to hydrological state variables. This allows using geophysical data as indirect hydrological observables, while the coupling with a flow-and transport simulator ensures physical consistency.Future research avenues include investigating the validity of different coupling strategies at various scales, the spatial statistics of near-surface petrophysical relationships, the influence of the model conceptualization, fully probabilistic joint inversions, and how to include complex prior information in the joint inversion.

A Review of Geophysical Methods for Soil Structure Characterization

“…Inversion (e.g., Menke, ) is needed to translate geophysical data into geophysical properties. The resolution and robustness of geophysical inversion results are often improved by considering multiple data sets or information gained from other types of geophysical data (Linde & Doetsch, ). A more advanced approach would, therefore, be to jointly invert the data by directly targeting properties of interest.…”

“…The anecdotal applications described above clearly point to the need for methods that fuse spatial and temporal geophysical information to derive quantitative metrics related to soil structure. Such methods could be fashioned after large‐scale hydrological and climate models (Looy et al, ) or, in the context of geophysics, could use coupled hydrogeophysical inversion to infer subsurface properties (Linde & Doetsch, ). In such an approach, the inverse problem is parameterized in terms of hydrological properties.…”

Petrophysical Joint Inversion Applied to Alpine Permafrost Field Sites to Image Subsurface Ice, Water, Air, and Rock Contents

“…Zhang and Morgan (1997) can be counted among the first to develop joint inversion strategies for physically uncorrelated datasets (e.g., seismic velocities and electrical resistivities). Many modern joint inversion algorithms have been developed to improve the inversion results, reduce the uncertainties and incorporate a priori knowledge (e.g., Gallardo and Meju, 2004;Doetsch et al, 2010;Karaoulis et al, 2013;Garofalo et al, 2015;Linde and Doetsch, 2016;Hellman et al, 2017).…”

Integrating Electromagnetic Data with Other Geophysical Observations for Enhanced Imaging of the Earth: A Tutorial and Review

“…Integrated methods are now applied in a wide range of fields, and recent reviews have been published on joint inversion in hydrogeophysics (Linde and Doetsch 2016), mineral exploration , hydrocarbon exploration (Moorkamp et al 2016b), lithospheric imaging (Afonso et al 2016) and deep mantle studies ). Here, I will focus on some of the most recent work and aspects that have not been fully covered by these reviews.…”