| 1. |
- Kessouri, Pauline, et al.
(author)
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Induced polarization applied to biogeophysics: recent advances and future prospects
- 2019
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In: Near Surface Geophysics. - : Wiley. - 1873-0604 .- 1569-4445. ; 17:6, s. 595-621
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Journal article (peer-reviewed)abstract
- This paper provides an update on the fast-evolving topic of the induced polarization (IP) method applied to biogeophysics. It emphasizes new understandings of the IP phenomena associated with biological activity, pointing out new developments and applications, and identifying existing knowledge gaps. The focus is on the use of IP as related to living organisms, including micro-organisms and plants (both roots and stems). We first discuss observed links between the IP signal and microbial cell structure, activity and biofilm formation. We provide an up-to-date conceptual model of the electrical behavior of the microbial cell and biofilm and examine the role of extracellular electron transfer mechanisms on the functionality and development of biofilms. We review the latest biogeophysical studies, including work on hydrocarbon biodegradation, contaminant sequestration, soil strengthening and peatland characterization. We then elaborate on the IP signature of the plant root zone, relying on a state-of-the-art conceptual model of the biogeophysical mechanisms of a plant root cell. The first laboratory surveys show that single roots and root system are highly polarizable. They also present encouraging results for imaging the root system embeded in a medium and gaining information on the mass density, the structure or the physiological characteristics of the root system. IP is also used to characterize wood and tree structures in the lab but also at the field scale, through tomography of the stem. Finally, we discuss up- and down-scaling between lab and field studies as well as joint interpretation. We emphasize the need for intermediate scale studies and the benefits of using IP as a time-lapse monitoring method. We conclude with the promising integration of IP in global mechanistic models to better understand and quantify subsurface biogeochemical processes.
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| 2. |
- Kemna, Andreas, et al.
(author)
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An overview of the spectral induced polarization method for near-surface applications
- 2012
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In: Near Surface Geophysics. - : Wiley. - 1873-0604 .- 1569-4445. ; 10:6, s. 453-468
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Journal article (peer-reviewed)abstract
- Over the last 15 years significant advancements in induced polarization (IP) research have taken place, particularly with respect to spectral IP (SIP), concerning the understanding of the mechanisms of the IP phenomenon, the conduction of accurate and broadband laboratory measurements, the modelling and inversion of IF data for imaging purposes and the increasing application of the method in near-surface investigations. We summarize here the current state of the science of the SIP method for near-surface applications and describe which aspects still represent open issues and should be the focus of future research efforts. Significant progress has been made over the last decade in the understanding of the microscopic mechanisms of IP; however, integrated mechanistic models involving different possible polarization processes at the grain/pore scale are still lacking. A prerequisite for the advances in the mechanistic understanding of IP was the development of improved laboratory instrumentation, which has led to a continuously growing data base of SIP measurements on various soil and rock samples. We summarize the experience of numerous experimental studies by formulating key recommendations for reliable SIP laboratory measurements. To make use of the established theoretical and empirical relationships between SIP characteristics and target petrophysical properties at the field scale, sophisticated forward modelling and inversion algorithms are needed. Considerable progress has also been made in this field, in particular with the development of complex resistivity algorithms allowing the modelling and inversion of IF data in the frequency domain. The ultimate goal for the future are algorithms and codes for the integral inversion of 3D, time-lapse and multi-frequency IF data, which defines a 5D inversion problem involving the dimensions space (for imaging), time (for monitoring) and frequency (for spectroscopy). We also offer guidelines for reliable and accurate measurements of IP spectra, which are essential for improved understanding of IP mechanisms and their links to physical, chemical and biological properties of interest. We believe that the SIP method offers potential for subsurface structure and process characterization, in particular in hydrogeophysical and biogeophysical studies.
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| 3. |
- Martin, Tina, et al.
(author)
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Comparison of TDIP and SIP measurements in the field scale
- 2018
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Conference paper (peer-reviewed)abstract
- The frequency-dependence of the induced polarization effect (IP), in the so-called spectral IP (SIP), has been demonstrated to be strongly correlated to important parameters in hydrogeological and environmental investigations. This has prompted the development of measuring instruments and modelling techniques towards the collection of laboratory and field data with enhanced accuracy and at a broader frequency bandwidth. Although SIP datasets were traditionally collected in the frequency-domain (FDIP), recent developments have demonstrated the capabilities to solve for the frequency-dependence of the complex conductivity through the inversion of measurements collected in the time-domain (TDIP). In recent years comparison of both methods has been conducted in a few studies; however, mostly related to the imaging results and not the actual signal-strength and sources of error affecting TDIP and FDIP. In particular, the EM-coupling is a limiting factor for the application of petrophysical models (observed in laboratory) in field in both FDIP and TDIP. Hence, the aim of our investigations is comparison of the resulting frequency-dependence parameter at a broad frequency range resolved through FDIP and TDIP. Furthermore, a detailed discussion on the different sources of error effecting the IP data readings. To provide as fair comparison as practically possible for TDIP and FDIP measurements, we conducted measurements with different instruments. For FDIP we deployed measurements with the Radic-Research SIP 256C and MPT DAS-1; whereas ABEM Terrameter LS and IRIS Syscal Switch Pro were used for TDIP. We present our results regarding the analysis of data errors, performed through statistical analysis of the misfit between normal and reciprocals. Analyses of signal strength are evaluated through comparison of data collected at different electrode separation. Additionally, we present a comparison of the inversion results as obtained by different algorithms.
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| 4. |
- Martin, Tina, et al.
(author)
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Evaluation of spectral induced polarization field measurements in time and frequency domain
- 2020
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In: Journal of Applied Geophysics. - : Elsevier BV. - 0926-9851. ; 180
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Journal article (peer-reviewed)abstract
- Spectral induced polarization (SIP) measurements have been demonstrated to correlate with important parame-ters in hydrogeological and environmental investigations. Although SIP measurements were often collected in thefrequency domain (FDIP), recent developments have demonstrated the capabilities to solve for the frequency-de-pendence of the complex conductivity through measurements collected in the time domain (TDIP). Therefore,the aim of our field investigations is a comparison of the measured frequency-dependence at a broad frequencyrange resolved through FDIP and TDIP. In contrast to previous studies, we conducted measurements with dif-ferent instruments and measuring technologies for both FDIP and TDIP. This allows for investigating the robust-ness of different measurements and assessing various sources of errors, for the assessment of the advantages anddrawbacks from different measuring techniques. Our results demonstrate that data collected through differentinstruments are consistent. Apparent resistivity measurements as well as the inversion results revealed quantita-tively the same values for all instruments. The measurements of the IP effect are also comparable, particularlyFDIP readings in the low frequencies (< 10 Hz) revealed to be quantitatively the same for different instruments.TDIP measurements are consistent for data collected with both devices. As expected, the spatial distribution ofthe values is also consistent for low frequency data (in FDIP) and late times measurements in TDIP (> 0.1 s).However, data quality for higher frequencies in FDIP (i.e., early times in TDIP) show larger variations, whichreflects the differences between the instruments to deal with the electromagnetic contamination of the IP data.Concluded in general, the different instruments and measuring techniques can provide consistent responses forvarying signal-to-noise ratio and measuring configurations.
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| 5. |
- Martin, Tina, et al.
(author)
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Induzierte Polarisation in der Biogeophysik
- 2019
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In: DGG Kolloquium 2019 : Induzierte Polarisation - Induzierte Polarisation. - 0947-1944. ; , s. 59-71
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Book chapter (other academic/artistic)
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