{"title":"Recovering Induced Polarization Effects from 1-D Coupled Inversion of Transient Electromagnetic Data","authors":"Fereydoun Sharifi, Bülent Tezkan, Ismael M Ibraheem, Rainer Bergers, Pritam Yogeshwar","doi":"10.1093/gji/ggae237","DOIUrl":null,"url":null,"abstract":"Summary Induced Polarization (IP) effects can significantly affect and superimpose the inductive earth response, leading to heavily distorted data and, if overlooked, false geological interpretation. In this paper, we implemented the Levenberg-Marquardt (LM) and very fast simulated annealing (VFSA) algorithms to recover induced polarization effects from central loop transient electromagnetic (TEM) data. To incorporate the IP effect in the TEM response, we used the Cole-Cole parameterization, maximum phase angle (MPA), maximum imaginary conductivity (MIC), and Jeffrey transform of Cole-Cole parameters. The result of 1D forward calculation and inversion of synthetic TEM data revealed that the Cole-Cole parametrization is more robust and reliable than MPA, MIC, and Jeffrey transform, and that the synthetic data were well fitted and IP parameters well recovered using this model. However, the incorporation of the IP effect leads to a highly non-linear and non-unique inverse problem which requires an accurate starting model, especially for LM inversion. To evaluate the performance of our algorithm using field data, we carried out a 1D inversion of TEM data acquired along a profile that traverses a waste site located near Cologne, Germany. Furthermore, to obtain a priori information and validate the result of TEM data modeling, we conducted an electrical resistivity tomography (ERT) and time-domain IP (TDIP) survey along the TEM profile. A 2D inversion was used to retrieve the Cole-Cole parameters as input for TEM interpretation. By including the IP information, the TEM field data can be explained quantitively, and a consistent and improved interpretation of the waste body is achieved.","PeriodicalId":12519,"journal":{"name":"Geophysical Journal International","volume":"39 1","pages":""},"PeriodicalIF":2.8000,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geophysical Journal International","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1093/gji/ggae237","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
Summary Induced Polarization (IP) effects can significantly affect and superimpose the inductive earth response, leading to heavily distorted data and, if overlooked, false geological interpretation. In this paper, we implemented the Levenberg-Marquardt (LM) and very fast simulated annealing (VFSA) algorithms to recover induced polarization effects from central loop transient electromagnetic (TEM) data. To incorporate the IP effect in the TEM response, we used the Cole-Cole parameterization, maximum phase angle (MPA), maximum imaginary conductivity (MIC), and Jeffrey transform of Cole-Cole parameters. The result of 1D forward calculation and inversion of synthetic TEM data revealed that the Cole-Cole parametrization is more robust and reliable than MPA, MIC, and Jeffrey transform, and that the synthetic data were well fitted and IP parameters well recovered using this model. However, the incorporation of the IP effect leads to a highly non-linear and non-unique inverse problem which requires an accurate starting model, especially for LM inversion. To evaluate the performance of our algorithm using field data, we carried out a 1D inversion of TEM data acquired along a profile that traverses a waste site located near Cologne, Germany. Furthermore, to obtain a priori information and validate the result of TEM data modeling, we conducted an electrical resistivity tomography (ERT) and time-domain IP (TDIP) survey along the TEM profile. A 2D inversion was used to retrieve the Cole-Cole parameters as input for TEM interpretation. By including the IP information, the TEM field data can be explained quantitively, and a consistent and improved interpretation of the waste body is achieved.
摘要 感应极化(IP)效应会严重影响和叠加感应地球响应,导致数据严重失真,如果被忽视,还会造成错误的地质解释。在本文中,我们采用 Levenberg-Marquardt (LM) 算法和快速模拟退火 (VFSA) 算法,从中心环瞬态电磁 (TEM) 数据中恢复感应极化效应。为了将 IP 效应纳入 TEM 响应,我们使用了科尔-科尔参数化、最大相位角 (MPA)、最大虚电导率 (MIC) 和科尔-科尔参数的杰弗里变换。合成 TEM 数据的一维正演计算和反演结果表明,Cole-Cole 参数化比 MPA、MIC 和 Jeffrey 变换更加稳健可靠,而且使用该模型可以很好地拟合合成数据并恢复 IP 参数。然而,IP效应的加入导致了一个高度非线性和非唯一的逆问题,这就需要一个精确的起始模型,特别是对于 LM 反演。为了利用现场数据评估我们算法的性能,我们对沿着穿越德国科隆附近一个垃圾场的剖面获取的 TEM 数据进行了一维反演。此外,为了获得先验信息并验证 TEM 数据建模的结果,我们沿 TEM 剖面进行了电阻率层析成像 (ERT) 和时域 IP (TDIP) 勘测。二维反演用于检索 Cole-Cole 参数,作为 TEM 解释的输入。通过加入 IP 信息,可以对 TEM 现场数据进行量化解释,并实现对废料体的一致和更好的解释。
期刊介绍:
Geophysical Journal International publishes top quality research papers, express letters, invited review papers and book reviews on all aspects of theoretical, computational, applied and observational geophysics.