TY - JOUR

T1 - Improved hydrogeophysical imaging by structural coupling of 2D magnetic resonance and electrical resistivity tomography

AU - Skibbe, Nico

AU - Günther, Thomas

AU - Müller-Petke, Mike

N1 - Funding information: This research was supported by the Deutsche Forschungsgemein-schaft (German Research Foundation) under grant MU 3318/3-1. We thank the two anonymous reviewers and the editorial board for the work they put into the paper during the review process. We also would like to express our gratitude for the continuous work with C. Jiang, during the original field campaign as well as for the many fruitful discussions afterward.

PY - 2021/6/17

Y1 - 2021/6/17

N2 - Describing hydraulic properties in the subsurface in at least two dimensions is one of the main objectives in hydrogeophysics. However, due to the limited resolution and ambiguity of the individual methods, those images are often blurry. We have developed a methodology to combine two measuring methods, magnetic resonance tomography (MRT) and electrical resistivity tomography (ERT). To this end, we extend a structurally coupled cooperative inversion scheme to three parameters. It results in clearer images of the three main parameters: water content, relaxation time, and electrical resistivity; thus, there is a less ambiguous hydrogeophysical interpretation. Synthetic models demonstrate its effectiveness and show how the parameters of the coupling equation affect the images and how they can be chosen. Furthermore, we examine the influence of resistivity structures on the MRT kernel function. We apply the method to a roll-along MRT data set and a detailed ERT profile. As a final result, a hydraulic conductivity image is produced. Known ground-penetrating radar reflectors act as the ground truth and demonstrate that the obtained images are improved by the structural coupling.

AB - Describing hydraulic properties in the subsurface in at least two dimensions is one of the main objectives in hydrogeophysics. However, due to the limited resolution and ambiguity of the individual methods, those images are often blurry. We have developed a methodology to combine two measuring methods, magnetic resonance tomography (MRT) and electrical resistivity tomography (ERT). To this end, we extend a structurally coupled cooperative inversion scheme to three parameters. It results in clearer images of the three main parameters: water content, relaxation time, and electrical resistivity; thus, there is a less ambiguous hydrogeophysical interpretation. Synthetic models demonstrate its effectiveness and show how the parameters of the coupling equation affect the images and how they can be chosen. Furthermore, we examine the influence of resistivity structures on the MRT kernel function. We apply the method to a roll-along MRT data set and a detailed ERT profile. As a final result, a hydraulic conductivity image is produced. Known ground-penetrating radar reflectors act as the ground truth and demonstrate that the obtained images are improved by the structural coupling.

KW - 2D

KW - electrical/resistivity

KW - inversion

KW - nuclear magnetic resonance

UR - http://www.scopus.com/inward/record.url?scp=85112529615&partnerID=8YFLogxK

U2 - 10.1190/geo2020-0593.1

DO - 10.1190/geo2020-0593.1

M3 - Article

AN - SCOPUS:85112529615

VL - 86

SP - WB77-WB88

JO - GEOPHYSICS

JF - GEOPHYSICS

SN - 0016-8033

IS - 5

ER -