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Parameterization of anisotropic media by A-parameters Stud. Geophys. Geod. (IF 0.9) Pub Date : 2024-01-13 Ivan Pšenčík, Véronique Farra
Most common parameterization of anisotropic media is by twenty one independent elements aijkl of the density-normalized stiffness tensor or by twenty one independent elements Aαβ of the density-normalized matrix of elastic parameters in the Voigt notation. These parameters are commonly of significantly different sizes, are dimensional, in (km/s)2, often appear in combinations. We are offering an alternative
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On correct definition and use of normal heights in geodesy Stud. Geophys. Geod. (IF 0.9) Pub Date : 2024-01-13 Pavel Novák, Fernando Sansò
Physical heights is one of the most important topics in physical geodesy. Their original concept, introduced in the 19-th century, defined physical heights as lengths of plumblines of the Earth’s gravity field between the geoid and points of interest. There are orthometric heights of surface points, that have been traditionally estimated by spirit levelling and measured gravity; however, the knowledge
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Day to night shift in reflection height of VLF radio waves derived from IRI model electron density models Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-11-08 Tirumalaraju Madhavilatha, Pyla Peddi Naidu, Malladi Indira Devi
The Very Low Frequency (VLF) radio wave propagation characteristics play a very important role in understanding the behaviour of the D-region. The earth-ionosphere wave guide theory has been used to evaluate the reflection height of VLF radio waves using the electron density profiles obtained from the International Reference Ionosphere (IRI) 2012 and 2016 models. For calculating the conductivity parameter
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Anisotropy of out-of-phase magnetic susceptibility in titanomagnetite-bearing rocks due to weak field hysteresis Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-08-03 František Hrouda, Josef Ježek, Martin Chadima
Properties of the out-of-phase susceptibility (opMS) of rocks and artificial specimens whose opMS is due to weak-field hysteresis, containing magnetite and titanomagnetite, were investigated and theoretical relation between degrees of the in-phase susceptibility (ipMS) and opAMS was confirmed experimentally. Pure magnetite shows virtually no field dependence of ipMS and zero opMS in fields less than
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Self-similarity convolution neural network for seismic noise suppression in desert environment Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-08-03 Hongbo Lin, Xinyu Xu, Shigang Wang
Seismic signals are inevitably disturbed by random noise in the acquisition process, which greatly degrades seismic data. In order to improve the quality of seismic data, we propose a self-similarity convolutional neural network (SS-Net) for seismic data denoising by introducing the coherence of seismic events into convolutional neural network (CNN). The SS-Net consists of two modules, the directional
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Mesoproterozoic geomagnetic field strength from Nova Guarita mafic dykes (Amazon Craton) Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-07-04 Anita Di Chiara, Adrian R. Muxworthy, Ricrdo I. F. Trindade, Franklin Bispo-Santos, Evelyn B. Baker
Palaeointensity data from the Precambrian are key to understanding the timing of the Earth’s Inner Core Nucleation (ICN). Due to the scarcity of data, the ICN timing is still poorly constrained and is thought to have occurred between 2500 to 500 Ma. Numerical dynamo simulation models predict an increase in entropy, a stronger driving force for convection that could affect the field strength and show
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Medium- and long-term prediction of length-of-day changes with the combined singular spectrum analysis and neural networks Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-07-04 Yu Lei, Danning Zhao, Min Guo
Real-time estimates of the Earth orientation parameters (EOP) are currently unavailable for users owing to the delay caused by complex data processing and heavy computation procedures. Accurate short-term predictions of the EOP are therefore essential for several real-time applications such as navigation and tracking of interplanetary spacecrafts and precise orbit determination of Earth satellites
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A priori and effective estimation of variance factors based on the code chipping rate in BeiDou navigation satellite system positioning Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-05-18 Xuezhen Li, Zhetao Zhang, Yuan Li, Xiaomin Luo, Vagner G. Ferreira
In multi-frequency and multi-constellation BeiDou Navigation Satellite System (BDS), the observation type is increased, and the observation precision is inevitably different. Consequently, it is difficult to determine the variance factors of various observations. Variance component estimation can reasonably determine the weights of different types of observations and greatly improve positioning accuracy
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On the topographic bias by analytical continuation in geoid determination Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-04-25 Lars E. Sjöberg
We consider the topographic bias in gravimetric geoid determination when analytically downward continuing the disturbing potential from the Earth’s surface to sea level. The total bias is subdivided into those of the Bouguer shell or plate and the terrain. In this process, the potential of the Bouguer shell always has a downward continuation bias in the process, which increases with the square of the
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The gravitational potential and its first- and second-order partial derivatives of an ellipsoidal tesseroid based on the Cartesian integral kernel Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-03-21 Shuai Wang, Zhaoxi Chen, Longjun Qiu
Gravity forward modelling is a fundamental problem in the fields of geophysics and geodesy at regional and global scales. Considering the curvature of the Earth, tesseroids are suitable to accurately simulate the theoretical gravity field. In general, the spherical tesseroid is regarded as an ideal model, but it cannot consider the oblateness of the Earth. Therefore, we define an ellipsoidal tesseroid
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Numerical simulation and time-frequency analysis of borehole acoustic logging in fractured formations Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-01-11 Min Xiang, Ran An, Xinghua Qi
Currently, using the finite difference method to simulate millimeter-sized fractures in formations requires intensive calculations. However, only the time domain characteristics of the calculated borehole acoustic signal are often analysed, while the frequency domain characteristics are ignored. This study aims to obtain the time-frequency characteristics of full acoustic waveforms in different types
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Magnetic susceptibility in soil pedons developed on different parent rocks in Kerman province (Iran) Stud. Geophys. Geod. (IF 0.9) Pub Date : 2023-01-11 Elham Soleimani Sardoo, Mohammad Hady Farpoor, Majid Mahmoodabadi, Azam Jafari
Lithology and soil formation affect magnetic susceptibility and its distribution along soil pedons. Kerman province in Iran is typical for variable lithology. However, only limited data on soil magnetic susceptibility in this province and its relation to the lithology are available. We investigate the effect of soil properties and processes on magnetic susceptibility values of soils with different
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Regionally adjusted ground motion model: Case study of the ML6.2 (Mw6.4) Petrinja (Croatia) 2020 earthquake Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-11-14 Jakov Stanislav Uglešić, Filip Skendrović, Iva Lončar, Snježana Markušić, Davor Stanko
In the wake of recent 2020 ML ≥ 5.5 earthquakes in Croatia, Zagreb ML5.5 and Petrinja ML6.2, the insufficient instrumental network as well as the lack of regional ground motion prediction equation (GMPE) were identified as the drawbacks of our engineering community. The former is related to the quality definition of active seismicity (most of the instruments are installed in the southern part of Croatia
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Tracing real-valued reference rays in anisotropic viscoelastic media Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-11-14 Ludĕk Klimeš
The eikonal equation in an attenuating medium has the form of a complex—valued Hamilton—Jacobi equation and must be solved in terms of the complex—valued travel time. A very suitable approximate method for calculating the complex—valued travel time right in real space is represented by the perturbation from the reference travel time calculated along the real—valued reference rays to the complex—valued
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Hybrid geoid model over peninsular Malaysia (PMHG2020) using two approaches Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-11-14 Muhammad Faiz Pa’suya, Ami Hassan Md Din, Ramazan Alpay Abbak, Mohammad Hanif Hamden, Nornajihah Mohammad Yazid, Mohamad Azril Che Aziz, Mohd Adhar Abd Samad
We describe the development of a hybrid geoid model for Peninsular Malaysia, based on two approaches. The first approach is utilising an ordinary method fitting the gravimetric geoid to the geometric undulation derived from GNSS-levelling data; the second approach directly fits the gravimetric geoid to the reference mean sea level derived from the tide measurements of Port Klang tide gauge station
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New methods for numerical evaluation of ultra-high degree and order associated Legendre functions Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-11-14 Mehdi Goli, Ismael Foroughi, Pavel Novák
We improve the precision and computation speed of the fully-normalized associated Legendre functions (fnALFs) for ultra-high degrees and orders of spherical harmonic transforms. We take advantage of their numerical behaviour of and propose two new methods for solving an underflow/overflow problem in their calculation. We specifically discuss the application of the two methods in the fixed-order increasing-degree
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Extremely strong anisotropy of out-of-phase component of AC magnetic susceptibility in hematite single crystals and its origin Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-08-30 František Hrouda, Josef Ježek, Martin Chadima
So far unknown anisotropic properties of out-of-phase magnetic susceptibility (opMS) of hematite and their bearing on understanding the origin of hematite magnetism were investigated on example of four single crystals from Minas Gerais, Brazil. The research comprised measurement of directional variation of field-dependent and frequency-dependent opMS and testing whether the anisotropy of opMS can be
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Anisotropic VSP reverse-time migration with optimal pure acoustic wave and complex wavefield separation Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-08-27 Zhiming Ren, Zhefeng Wei, Chenghong Zhu
Ignoring anisotropy characteristic of subsurface media may lead to misplaced images and low resolution of the target for the reverse-time migration (RTM). The mature anisotropic RTM methods are mainly based on the pseudoacoustic wave approximation. Although these schemes have high computational efficiency, most of pseudo-acoustic wave equations (PWEs) inevitably encounter SV-wave artifacts or instability
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Velocity analysis of noisy seismic data based on RSVD weighted semblance Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-04-30 Yankai Xu, Siyuan Cao, Xiao Pan, Siyuan Chen, Mingjun Cai, Jialiang Zhang
The accuracy of velocity spectrum affects the subsequent processing of seismic data. Though the singular value decomposition (SVD) weighted semblance has a higher velocity resolution than conventional semblance, its performance is degraded for noisy seismic data. A rectified SVD weighted semblance method (RSVD), aiming to improve the accuracy of velocity spectrum for seismic data contaminated by noise
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Erratum to “Improving the accuracy of the expanded anisotropic eikonal equation at larger offsets using Levin’s T-transformation” Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-04-04 Humbang Purba,Awali Priyono,Wahyu Triyoso,Mochamad Apri
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Evaluation of latest marine gravity field models derived from satellite altimetry over the Gulf of Guinea (Central Africa) with shipborne gravity data Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-04-04 Paul Gautier Kamto, Loudi Yap, Sévérin Nguiya, Ludovic Houetchak Kandé, Joseph Kamguia
The marine gravity field is vital for mapping various submarine geological and tectonic structures, also for computation of high-resolution gravimetric geoid. This study aims to evaluate the accuracy of two latest high-resolution marine gravity models derived from satellite altimetry (DTU17 and SSv27.1) using shipborne gravity data and to pruduce high-precision gravity field over the Gulf of Guinea
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Expressions for the calculation of isotropic Gaussian filter kernels in the spherical harmonic domain Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-04-04 Dimitrios Piretzidis, Michael G. Sideris
The isotropic Gaussian filter has been used extensively in Gravity Recovery and Climate Experiment (GRACE) temporal gravity field solutions, and is still being applied to GRACE Follow-On products to remove high-frequency errors and improve the estimation of mass transport events on the Earth’s surface. For such applications, the only known rigorous method to calculate the spherical harmonic coefficients
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Rotationally invariant viscoelastic medium with a non-symmetric stiffness matrix Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-02-08 Luděk Klimeš
The stiffness matrix of a viscoelastic medium is symmetric in the low—frequency and high—frequency limits, but not for finite frequencies. We thus consider a non—symmetric stiffness matrix in this paper. We determine the general form of a rotationally invariant non—symmetric stiffness matrix of a viscoelastic medium. It is described by three additional complex—valued parameters in comparison with a
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Geoelectrical imaging and spatial distribution of alluvial materials of the Sanaga River (Cameroon, Central Africa) Stud. Geophys. Geod. (IF 0.9) Pub Date : 2022-02-08 Renaud Menanga Tokouet, Joseph Quentin Yene Atangana, Mbida Yem, Emile Ekomane, Ferdinand Deffo, Florent Daniel Akono, Mike-Franck Mienlam Essi
Recent research has shown that the floodplains of the Sanaga river catchment contain significant resources of minerals suitable for industry. However, these studies were carried out in large grids, and do not allow for detailed specification of the geometry of the identified resources. The aim of this study is to minimize the uncertainties observed in the characterization of these deposits using two
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Velocity structure and its relation to the seismicity of Datong Window and adjacent regions in Shanxi Province, North China Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-12-12 Wang, Xia, Song, Meiqing, Zhang, Na, Shen, Jinchao
Datong Window is at the junction of Datong Basin and Liulengshan Range in the northern part of Shanxi Graben, China. It is important to analyze the relationship between the frequency of small earthquakes and the deep velocity structure in this region since the earthquake swarm in 1989 with the maximum surface-wave magnitude Ms of 5.9. A high-resolution 3D P-wave velocity model of the crust in this
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Application of the nonlinear optimisation in regional gravity field modelling using spherical radial base functions Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-12-12 Hany Mahbuby, Yazdan Amerian, Amirhossein Nikoofard, Mehdi Eshagh
The gravity field is a signature of the mass distribution and interior structure of the Earth, in addition to all its geodetic applications especially geoid determination and vertical datum unification. Determination of a regional gravity field model is an important subject and needs to be investigated and developed. Here, the spherical radial basis functions (SBFs) are applied in two scenarios for
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Two S-wave eigenvectors of the Christoffel matrix need not exist in anisotropic viscoelastic media Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-11-15 Luděk Klimeš
The 3×3×3×3 frequency-domain stiffness tensor is complex-valued in viscoelastic media. The 3 × 3 Christoffel matrix is then also complex-valued. Using a simple example, we demonstrate that a complex-valued Christoffel matrix need not have all three eigenvectors at an S-wave singularity, and we thus cannot apply the eigenvectors to calculating the phase-space derivatives of the Hamiltonian function
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Sensitivity Gaussian packets Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-11-15 Luděk Klimeš
Perturbations of elastic moduli and density can be decomposed into Gabor functions. The wave field scattered by the perturbations is then composed of waves scattered by the individual Gabor functions. The scattered waves can be estimated using the first-order Born approximation with the paraxial ray approximation. For a particular source generating a short-duration broad-band incident wave field with
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Error bounds for the spectral approximation of the potential of a homogeneous almost spherical body Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-09-04 Bucha, Blažej, Rossi, Lorenzo, Sansò, Fernando
Several kinds of approximation of the gravitational potential of a homogeneous body by truncated spherical harmonics series are in use in physical geodesy. However, only one of them is capable of a representation converging to the true potential in the whole layer between the Brillouin sphere and the Bjerhammar sphere of the body. We aim at providing various majorizations, namely upper bounds, of the
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The stability criterion for downward continuation of surface gravity data with various spatial resolutions over Ireland Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-09-04 Sajjadi, Sajjad, Martinec, Zdeněk, Prendergast, Patrick, Hagedoorn, Jan, Šachl, Libor
The differences between local and reference geopotential values are the fundamental quantities of interest in the geodetic boundary value problem approach for connecting independent height reference frames. The local gravity potential values are usually derived from gravimetric and geometric geoid undulations. In determining the short-wavelength components of the gravimetric geoid, a harmonic or analytical
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Relationship between soil magnetic susceptibility enhancement and precipitation in Cretaceous paleosols Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-07-28 Liu, Xiaojing, Chen, Jiasheng, Xie, Qin
Magnetic susceptibility (MS) is widely used for paleoclimate reconstruction. In one of the previous studies, data from 12 locations of modern middle- and low-latitude soils revealed that MS increases with increasing precipitation from approximately 200 to 1000–1200 mm yr−1 and then decreases with further precipitation. However, as a result of diverse sediment sources from different locations, the MS
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Erratum to “Bounds and averages of seismic quality factor Q” Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-07-28 Ayman N. Qadrouh,José M. Carcione,Mamdoh Alajmi,Jing Ba
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Two-dimensional magnetotelluric data inversion using Lanczos bidiagonalization method with active constraint balancing Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-04-13 Faegheh Mina Araghi, Mirsattar Meshinchi-Asl, Ali Nejati Kalateh, Mahmoud Mirzaei
The magnetotelluric (MT) technique is an electromagnetic geophysical method, which is widely used as a complementary to seismic surveys for exploration of hydrocarbon reservoirs. In the inversion process, the method of matrix inverse calculation has a considerable effect on the speed of the inversion and the quality of obtained models. Lanczos Bidiagonalization (LB) method has been reported to be a
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An alternative geoid model for Africa using the shallow-layer method Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-04-08 Mostafa Ashry, Wen-Bin Shen, Hussein A. Abd-Elmotaal
The aim of the current investigation is to determine an alternative geoid model for Africa using the shallow-layer method. The shallow-layer method, following the basic definition of the geoid, differs essentially from the traditional geoid determination techniques (Stokes and Molodensky) that it doesn’t need real gravity data. It comes from the definition of the geoid. Here, the shallow-layer method
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Alternative formulae for robust Weighted Total Least-Squares solutions for Errors-In-Variables models Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-03-12 Zhipeng Lv, Lifen Sui
Weighted Total Least-Squares (WTLS) can optimally solve the issue of parameter estimation in the Errors-In-Variables (EIV) model; however, this method is relatively sensitive to outliers that may exist in the observation vector and/or the coefficient matrix. Hence, an attempt to identify/suppress those outliers is in progress and will ultimately lead to a novel robust estimation procedure similar to
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Comparison of three methods for computing the gravitational attraction of tesseroids at satellite altitude Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-03-12 Longjun Qiu, Zhaoxi Chen
Global gravity modelling is one of the most important issues in geophysics and geodesy. Because a tesseroid model comprises the curvature of the Earth, the computation methods for the gravitational potential of tesseroids and its first-order derivatives in spherical coordinates are attracting great attention in recent years. In this paper we deal with the numerical evaluation of the radial component
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Assessment of state of earth dam of Elchovka settling pond by combination of electromagnetic soundings and polarization methods Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-02-22 Vadim A. Davydov, Olga I. Fedorova, Vitaliy Y. Gorshkov, Sergey V. Baydikov
Earth dams are constantly under the hydraulic pressure. Their long-term operation leads to arising of zones of increased water cut and filtration in body and base of dams. This weakens dam’s strength. Geophysical methods can be used to control condition of the soil structures. We describe the research results of the Elchovka earth dam by a complex of electrometric methods, as they are most sensitive
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Velocity structure of the upper crust beneath the Jiaonan uplift and its adjacent areas, China Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-02-15 Jinchao Shen, Song Yao
The Jiaonan uplift and its adjacent areas (JUAA) are the result of collision and amalgamation of the North China plate and Yangtze plate. In this area, the tectonic environment is complex and crustal deformation is strong. However, detailed and in-depth study of the upper crustal structure and medium properties in the JUAA has not previously been performed. The high-resolution three-dimensional crustal
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Post-stack seismic data interpolation using a fast non-local similarity matching algorithm Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-02-15 Siyuan Chen, Siyuan Cao, Haokun Wang, Yaoguang Sun, Yankai Xu
In the process of seismic data acquisition, there are often missing seismic traces in seismic records, so it is necessary to reconstruct the missing data to provide high-quality data for subsequent seismic data migration and reservoir inversion. Traditional interpolation methods for post-stack seismic data are based on the sparse constraint in the frequency-wavenumber (f-k) domain. However, the data
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Vertical distribution of magnetic susceptibility as affected by pedoenvironmental factors along an arid and semi-arid transect, Fars Province, Iran Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-02-04 Sahar Taghdis, Mohammad Hady Farpoor, Majid Fekri, Majid Mahmoodabadi
Soil magnetism provides valuable information about soil-landscape relationships and soil evolution. However, only limited number of studies on the relationship between soil magnetic properties and soil forming factors and processes, especially in arid and semi-arid regions, are available. The aim of this study was to determine vertical distribution of soil magnetic susceptibility and selected pedoenvironmental
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Representation theorem for viscoelastic waves with a non-symmetric stiffness matrix Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-02-01 Luděk Klimeš
In an elastic medium, it was proved that the stiffness tensor is symmetric with respect to the exchange of the first pair of indices and the second pair of indices, but the proof does not apply to a viscoelastic medium. In this paper, we thus derive the representation theorem for viscoelastic waves in a medium with a non-symmetric stiffness matrix. The representation theorem expresses the wave field
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A data-driven method for time-varying wavelet extraction based on the local frequency spectrum Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-02-01 Yumeng Jiang, Siyuan Cao, Siyuan Chen, Duo Zheng
Seismic wavelet extraction always plays a central role in high-resolution seismic processing. Conventional methods assume that seismic data are stationary when a constant wavelet is considered, which ignores the time-varying characteristics of seismic wavelets. In reality, seismic data are nonstationary because of attenuation, scattering, and other physical processes during propagation, which means
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Recent Macaronesian kinematics from GNSS ground displacement analysis Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-01-08 Ignacio Barbero, Cristina Torrecillas, Raúl Páez, Gonçalo Prates, Manuel Berrocoso
Macaronesia is a complex oceanic region spanning three tectonic plates in the northeast Atlantic ocean. It is composed of four archipelagos, widely distributed and limited to the east by the Iberian Peninsula and north-western coast of Africa. This study aims to clarify recent Macaronesian kinematics from 19 GNSS stations located on the four archipelagos and the Iberian and African coastlines. The
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A new univariate deformation analysis approach considering displacements as model errors Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-01-08 Bahattin Erdogan, Serif Hekimoglu, Utkan Mustafa Durdag
In Conventional Deformation Analysis (CDA), at least two different epochs are adjusted by using the Least Squares Estimation (LSE) method and compared statistically. The effect of the geometry of the network is an essential part of the adjustment model and the LSE method smears the effects of the displaced point over the other nondisplaced points. In this study, to remove these spoiling effects and
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Mantle deformation and seismic anisotropy beneath Northeast India inferred from SKKS birefringence Stud. Geophys. Geod. (IF 0.9) Pub Date : 2021-01-08 Poulommi Mondal, Debasis D. Mohanty
The present study produces very new SKKS splitting measurements from the Northeast India, suggesting the region as tectonically more heterogeneous and complex in nature. It fills the gap of anisotropic parameters from an epicentral range of 140°–180° in order to understand the lithospheric deformation patterns of the terrain in a better way. The splitting parameters namely polarisation direction of
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Rate of seismic deformation in the Gulf of Aqaba inferred from moment-tensor summation Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-11-09 Sattam Almadani
This study aims to quantify the rate of coseismic deformation in the Gulf of Aqaba. Earthquake catalogue, Gutenberg-Richter relationship and fault plane solutions were integrated to measure the size and shape of deformation using the moment-tensor summation technique. First, the Gutenberg-Richter relationship was established using seismicity data from the period of 1964–2019. Then, the moment-tensor
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Exact line search method for using the L1-norm misfit function in full waveform inversion Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-11-09 Xiaona Ma, Guanghe Liang, Shanhui Xu, Zhiyuan Li, Haixin Feng
Full waveform inversion (FWI) is a non-linear inverse problem that can be sensitive to noise. The tolerance of the noise-interference characteristics depends on the types of misfit functions. To date, different misfit functions, such as the least-squares norm (L2), the least-absolute-value norm (L1), and combinations of the two (e.g., the Huber and hybrid criteria), have been applied to FWI. The L2
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Effect of a high-resolution global crustal model on gravimetric geoid determination: a case study in a mountainous region Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-10-27 Ramazan Alpay Abbak
A precise gravimetric geoid model is determined by using Stokes formula assuming that there is no topography above the geoid. Then, the geoid model is simply corrected by considering the constant crustal density of 2670 kg m−3 for topographical mass. In fact, the actual density of topographical mass differs about ±20% from the constant value. Recently a global crustal density model within 30″ resolution
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Modeling 3D acoustic-wave propagation using modified cuboid-based staggered-grid finite-difference methods with temporal and spatial high-order accuracy Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-10-27 Shigang Xu, Yang Liu
To improve the modeling accuracy and adaptability of traditional temporal second-order staggered-grid finite-difference (SFD) methods for 3D acoustic-wave modeling, we propose a modified time-space-domain temporal and spatial high-order SFD stencil on a cuboid grid. The grid nodes on a double-pyramid stencil and the standard orthogonality stencil are used to approximate temporal and spatial derivatives
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Gravity sparse inversion using the interior-point method and a general model weighting function Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-10-24 Wenwu Zhu, Junhuan Peng, Sanming Luo, Xiangang Meng, Jinzhao Liu, Chuandong Zhu
This study presents an optimized gravity-sparse inversion method. The proposed method minimizes the global objective function using interior-point method for boundary constraints and a general weighting function comprising the depth, compactness, and kernel weighting functions of the density models. For the compactness weighting function, practical experiments demonstrate that the recovered model becomes
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Stable optimization of finite-difference operators for seismic wave modeling Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-09-03 Jian Wang, Liu Hong
The finite difference scheme is now widely used in the reverse time migration and full waveform inversion. Their results are dependent on the accuracy of finite difference operators. In this paper, we combine the cosine function with the original window function to construct a new window function, in order to obtain higher precision finite difference operators. The absolute error curves of the optimized
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A stable regularization method of downward continuation of potential field Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-07-27 Jinpeng Li, Yingtang Zhang, Hongbo Fan, Zhining Li, Fucheng Sun
Downward continuation is known as one of the crucial steps in interpreting gravity or magnetic data. As the continuation depth and the influence of noise increases, the results of downward continuation become unstable. Based on the computation of the Chebyshev-Padé approximation function obtained by the Tikhonov regularization, this paper proposes a new regularized method intended for the downward
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Desert seismic data denoising based on energy spectrum analysis in empirical curvelet domain Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-07-18 Mo Li, Yue Li, Ning Wu, Yanan Tian
Desert seismic events are disturbed and contaminated by strong random noise, which complicates the subsequent processing, inversion, and interpretation of the data. Thus, noise suppression is an important task. The complex characteristics of random noise in desert seismic records differ completely from those of Gaussian white noise such that they are non-stationary, non-Gaussian, non-linear and low
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Improving the accuracy of the expanded anisotropic eikonal equation at larger offsets using Levin T-transformation Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-07-15 Humbang Purba, Awali Priyono, Wahyu Triyoso, Mochamad Apri
In an anisotropic model, traveltime can be determined approximately by numerical solution of the eikonal equation in terms of an anellipticity parameter η, using perturbation theory. However, its accuracy decreases under the effect of strong anisotropy at larger offsets. It becomes invalid for determining normal moveout velocity and anellipticity parameter in seismic processing. We propose a new approach
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Impact of environmental phenomena on continuous relative gravity measurements performed in urban area Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-06-22 Branislav Hábel, Juraj Janák, Juraj Papčo, Miloš Val’ko
The relative monitoring gravimeter gPhoneX #108 was installed in the building of Faculty of Civil Engineering of the Slovak University of Technology in Bratislava in the beginning of 2016. Main purpose of the paper is to analyze how external environmental phenomena generating non-gravitational signal, such as strong human activity, ambient noise and tilting of observing site due to solar radiation
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Quality assessment of global gravity field models in coastal zones: A case study using astrogeodetic vertical deflections in Istanbul, Turkey Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-06-06 Müge Albayrak, Christian Hirt, Sébastien Guillaume, Kerem Halicioglu, M. Tevfik Özlüdemir, C. K. Shum
We present the first high-precision astrogeodetic vertical deflection (VD) observations collected in Istanbul, Turkey, using a novel lightweight total station integrated with a charge-coupled device (CCD) camera, the QDaedalus system. The observed VDs are unique in that, they were measured for the first time in Istanbul, and they form Turkey’s first dense astrogeodetic network. To establish the Istanbul
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Incidence of solar cycle 24 in nighttime foF2 long-term trends for two Japanese ionospheric stations Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-06-06 Blas F. de Haro Barbás, Ana G. Elias, Mariano Fagre, Bruno S. Zossi
Ionospheric long-term trend studies are of great scientific interest since they contribute to the more general and controversial climatic change issue. In this paper we analyze the effect of the inclusion of solar cycle 24 on estimation of the nighttime trend of the critical frequency of ionospheric F2 layer (foF2) for Kokubunji (35.7°N, 139.5°E) and Wakkanai (45.4°N, 141.7°E), two mid-latitude Japanese
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A technique to reduce the edge-effect in least squares extrapolation for enhanced Earth orientation prediction Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-05-30 Danning Zhao, Yu Lei
A well-known property of the classical least squares (LS) extrapolation is that a fit is best in the middle of the time span of observed data, but worse near the beginning and end of the time span. This phenomenon is called the edge effect in data processing. The goal of this work is to reduce the edge effect to improve predictions of the Earth rotation parameters (ERP), which comprise the Earth’s
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Archaeomagnetic investigations in Bolgar (Tatarstan) Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-04-25 Lina R. Kosareva, Dilyara M. Kuzina, Danis K. Nurgaliev, Airat G. Sitdikov, Olga V. Luneva, Damir I. Khasanov, Neil Suttie, Simo Spassov
The objective of this study is to provide a well-dated point for a future palaeosecular variation (PSV) reference curve for western Russia. For this purpose archaeomagnetic and magnetic property analyses were carried out on a pottery kiln unearthed at the UNESCO World Heritage site of ancient Bolgar, having a rather precise age dating. The archaeological context provided an age between 1340 and 1360
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Simple numerical tests for ocean tidal models Stud. Geophys. Geod. (IF 0.9) Pub Date : 2020-04-25 Libor Šachl, David Einšpigel, Zdeněk Martinec
There is a growing interest in tidal effects on the global wind-driven oceanic circulation. Tidal models used in such investigations have been verified by comparison with satellite and tide gauge data, but synthetic tests have not been published. In this paper we present three numerical tests in spherical geometry, which are suitable for testing the tidal component of global ocean models. The first