Article
Geosciences, Multidisciplinary
Sudha Agrahari, Buelent Tezkan, Bernhard Siemon
Summary: Researchers extensively studied a Pleistocene buried valley, the Cuxhaven Valley, in Northern Germany using three different electromagnetic methods to analyze the underground structures, providing a basis for understanding the geological formations at various depths.
JOURNAL OF APPLIED GEOPHYSICS
(2021)
Article
Geochemistry & Geophysics
Ji Cai, Pritam Yogeshwar, Wiebke Moerbe, Maria Smirnova, Amir Haroon, Michael Becken, Buelent Tezkan
Summary: Various electromagnetic techniques have been developed for exploring natural resources. This study focuses on the frequency-domain semi-airborne controlled source electromagnetic (semi-AEM) method, which combines ground and airborne techniques to survey the subsurface down to approximately 1000 m. The study presents a 2-D joint inversion algorithm to interpret semi-AEM data together with information from long-offset transient electromagnetics (LOTEM) data. The results show that the two methods have complementary subsurface resolution capabilities, but there are discrepancies between individual and joint inversion results due to different measurement configurations, components, and error weighting of the data sets. Synthetic modelling studies suggest that flexible land-based configurations with sparse receiver locations can be combined with semi-AEM without significant loss of target resolution.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Ahmad Shahir bin Saleh, Max A. Meju, Nur Azwin Binti Ismail, Mohd Nawawi bin Mohd Nordin
Summary: The use of seismic-derived structure tensor for guiding the inversion of non-seismic data is gaining attention. This paper focuses on marine magnetotellurics (MT) and studies the practical aspects of seismic-guided electromagnetic (EM) inversion. By comparing different options, the study shows that an initial model guided by seismic FWI velocity gives the best match to well logs. The choice of structure tensor is important, and the structure tensor from APSDM reflectivity data is preferred.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geosciences, Multidisciplinary
Duygu Kiyan, Volker Rath, Mark R. Muller, Mohammednur D. Ture, James Hodgson
Summary: Over the past decade, Geological Survey Ireland has acquired airborne electromagnetic data for the Tellus project, and developed the open-source toolbox aempy to facilitate data interpretation and modeling. Implemented in Python, aempy is adaptable for specific educational and research objectives, allowing for 1-D inversion modeling with processed frequency-domain airborne electromagnetic data.
JOURNAL OF APPLIED GEOPHYSICS
(2022)
Article
Geochemistry & Geophysics
Osama Elghrabawy, Khaled Khalifa
Summary: This study presents a 3-D stripping inversion over the Hodein Basin area in the Southeastern Desert using the Fourier approach and evaluates the method based on data constraints. The results show that the study area is characterized by a broad basin directed in the NW direction and dissected by normal faults, forming small subbasins.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Engineering, Electrical & Electronic
Ergun Simsek
Summary: This work investigates how different measurement setups affect the accuracy of machine learning algorithms in electromagnetic inversion problems and finds that deep learning outperforms other techniques. Increasing the number of antennas and avoiding uniform grids for training data sets can improve efficiency, and multifrequency training with fewer antennas leads to more accurate inversions.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Geochemistry & Geophysics
Ronghua Peng, Pritam Yogeshwar, Yajun Liu, Xiangyun Hu
Summary: Central loop TEM data is often interpreted using conventional 1-D or quasi-2-D inversion techniques. A transdimensional Markov chain Monte Carlo method is proposed for the quasi-2-D inversion of TEM data using a Bayesian inference framework. The method automatically determines the model complexity and is validated using synthetic data and field data from a floating TEM survey.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Chemistry, Multidisciplinary
Rita Mocci, Evelina Colacino, Lidia De Luca, Claudia Fattuoni, Andrea Porcheddu, Francesco Delogu
Summary: The Beckmann rearrangement, discovered over a century ago, remains compliant with green chemistry principles and sustainable development aspects. A sustainable mechanochemical procedure was developed to design new amide frameworks via a cut-and-paste process on the oxime backbone, utilizing inexpensive reagents to prepare various amides, including marketable compounds like epsilon-caprolactam and the API paracetamol, in good to high yields. This solvent-free procedure was also successfully extended to ketones serving as oxime precursors.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Geochemistry & Geophysics
Emad Ghalenoei, Jan Dettmer, Mohammed Y. Ali, Jeong Woo Kim
Summary: This paper presents a new non-linear Bayesian inversion method to address the limitations of conventional regularized inversion. The method utilizes trans-dimensional partitioning and estimation to resolve subsurface structures and reduce error correlations in 2-D potential-field data. The method is applied to simulated data and field data, demonstrating its effectiveness in resolving structures and reducing error correlations.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Fu Yin, Baoshan Wang
Summary: Accurate earthquake source parameter estimation is crucial for seismic source studies and seismic hazard assessments. The traditional workflow of source parameter estimation often suffers from cumulative uncertainties. In this study, a new Python package called MCMTpy is introduced, which utilizes the Cut-And-Paste algorithm and Bayesian inference to integrate the source location and focal mechanism inversions into one workflow. The effectiveness of MCMTpy is demonstrated through applications to real earthquake events.
SEISMOLOGICAL RESEARCH LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Marcin Morawiec, Filip Wilczynski
Summary: This article presents the electric drive system of a five-phase induction machine using a current source inverter. The proposed control structure allows for independent control of the machine's state variables and injection of the third harmonic, resulting in an increased electromagnetic torque value.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Geochemistry & Geophysics
Shan Lu, Bingyang Liang, Jianwen Wang, Feng Han, Qing Huo Liu
Summary: This letter discusses the application of supervised descent method (SDM) in solving controlled-source electromagnetic inversion. By learning the descent direction offline and combining it with measured data and forward model online, the efficiency of SDM is significantly enhanced. Both synthesized and field-measured data are used to verify the feasibility and efficiency of SDM, while also studying its learning ability.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2022)
Article
Environmental Sciences
Tao He, Lei Cui, Pengbo Wang, Yanan Guo, Lei Zhuang
Summary: This paper presents a novel ultra-high resolution imaging algorithm based on an accurate high-order 2-D spectrum. The algorithm replaces the range models in the defective spectrum with a polynomial range model and calculates a new spectrum using the Lagrange inversion formula. The algorithm compensates for the range high-order term and eliminates the range chirp rate space variance using a cubic phase term. Simulation results demonstrate that the proposed algorithm can achieve imaging processing with a 0.25 m resolution in the azimuth and range, validating its feasibility.
Article
Geochemistry & Geophysics
Sh Bronson Aimol, G. Srinivasa Rao, Thinesh Kumar, Rama Chandrudu Arasada
Summary: In this study, a fast and efficient inversion algorithm based on machine learning techniques is developed to interpret the magnetic anomalies produced by 2D dike bodies. The algorithm shows good agreement with true model parameters and previous studies when applied to both synthetic data and real case examples.
Article
Engineering, Electrical & Electronic
Li-Ye Xiao, Ronghan Hong, Le-Yi Zhao, Hao-Jie Hu, Qing Huo Liu
Summary: This paper proposes a hybrid neural network electromagnetic inversion scheme for microwave human brain imaging, which combines shallow and deep neural networks to reduce computational costs and solve the high contrast inverse problem. The proposed scheme shows superior super-resolution inversion capabilities for human brain imaging.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Geochemistry & Geophysics
Bernhard Siemon, Stephan Costabel, Wolfgang Voss, Uwe Meyer, Nico Deus, Joerg Elbracht, Thomas Guenther, Helga Wiederhold
Article
Geosciences, Multidisciplinary
M. Scheunert, A. Ullmann, M. Afanasjew, R. -U. Boerner, B. Siemon, K. Spitzer
JOURNAL OF APPLIED GEOPHYSICS
(2016)
Article
Geosciences, Multidisciplinary
Stephan Costabel, Bernhard Siemon, Georg Houben, Thomas Guenther
JOURNAL OF APPLIED GEOPHYSICS
(2017)
Article
Environmental Sciences
Joost R. Delsman, Esther S. van Baaren, Bernhard Siemon, Willem Dabekaussen, Marios C. Karaoulis, Pieter S. Pauw, Tommer Vermaas, Huite Bootsma, Perry G. B. de Louw, Jan L. Gunnink, C. Wim Dubelaar, Armin Menkovic, Annika Steuer, Uwe Meyer, Andre Revil, Gualbert H. P. Oude Essink
ENVIRONMENTAL RESEARCH LETTERS
(2018)
Article
Geochemistry & Geophysics
Sudha, Buelent Tezkan, Bernhard Siemon
GEOPHYSICAL PROSPECTING
(2014)
Article
Geosciences, Multidisciplinary
D. Steinmetz, J. Winsemann, C. Brandes, B. Siemon, A. Ullmann, H. Wiederhold, U. Meyer
NETHERLANDS JOURNAL OF GEOSCIENCES-GEOLOGIE EN MIJNBOUW
(2015)
Article
Environmental Sciences
Jude King, Gualbert Oude Essink, Marios Karaolis, Bernhard Siemon, Marc. F. P. Bierkens
WATER RESOURCES RESEARCH
(2018)
Article
Environmental Sciences
Bernhard Siemon, Malte Ibs-von Seht, Stefan Frank
Article
Environmental Sciences
Bernhard Siemon, Malte Ibs-von Seht, Annika Steuer, Nico Deus, Helga Wiederhold
Article
Geochemistry & Geophysics
Hernan Ugalde, William Morris, Yuleika Madriz, Moritz Kirsch, Richard Gloaguen, Michael Schneider, Markus Schiffler, Bernhard Siemon, Tristan Freville, Marc Munschy
Summary: Magnetic data can be acquired from different platforms and sensors to detect magnetic anomalies associated with mineral content. Prior measurements and lab testing can provide information on physical contrast and magnetic properties. In this study, magnetic patterns of skarn bodies in Germany were analyzed.
GEOPHYSICAL PROSPECTING
(2022)
Proceedings Paper
Environmental Sciences
Bernhard Siemon, Annika Steuer, Nico Deus, Joerg Elbracht
25TH SALT WATER INTRUSION MEETING (SWIM 2018)
(2018)
Proceedings Paper
Environmental Sciences
Mohammad Azizur Rahman, Eva Gonzalez, Helga Wiederhold, Nico Deus, Joerg Elbracht, Bernhard Siemon
25TH SALT WATER INTRUSION MEETING (SWIM 2018)
(2018)
Article
Geochemistry & Geophysics
Jan L. Gunnink, Bernhard Siemon
NEAR SURFACE GEOPHYSICS
(2015)
Article
Geosciences, Multidisciplinary
M. Faneca Sanchez, J. L. Gunnink, E. S. van Baaren, G. H. P. Oude Essink, B. Siemon, E. Auken, W. Elderhorst, P. G. B. de Louw
HYDROLOGY AND EARTH SYSTEM SCIENCES
(2012)