scholarly journals A combined Euler deconvolution and tilt angle method for interpretation of magnetic data in the South region

2019 ◽  
Vol 22 (2) ◽  
pp. 219-227
Author(s):  
Hai Hong Nguyen ◽  
Liet Van Dang ◽  
Vuong Van Vo
Keyword(s):  
Tilt Angle ◽  
Longitudinal Direction ◽  
Geological Structure ◽  
Magnetic Data ◽  
Euler Deconvolution ◽  
Magnetic Pole ◽  
The South ◽  
Dip Angle ◽  
Angle Method ◽  
Total Horizontal Derivative

Introduction: The purpose of this paper is to determinate the position, depth, dip direction and dip angle the faults in the South region of Vietnam from the total magnetic intensity anomalies, that reduced to the magnetic pole (RTP). Methods: Based on the Oasis Montaj software, we proposed a new way to compute the positions and the depth to the top of the faults by combining the Tilt angle and the Euler deconvolution methods. In addition, the angle and direction of the dip of theses faults were also determined by considering maximum of the total horizontal derivative of the RTP upward continuation at the different height levels. Results: The results show that there are 12 faults along the longitudinal direction, latitudinal direction, Northwest — Southeast direction and Northeast — Southwest direction with the mazimum depth is about 3100 m and the dip angle changes in the range of 65-82◦. Results: These indicate that these methods are valuable tools for specifying the characteristics of geology, contribute to give and confirm the useful information on geological structure in the South region of Vietnam.  

scholarly journals Evaluation of the Solar Quiet Reference Field (SQRF) Model for Space Weather Applications in the South America Magnetic Anomaly

2021 ◽  
Author(s):  
Sony Su Chen ◽  
Clezio Marcos Denardini ◽  
Láysa C. A. Resende ◽  
Ronan A. J. Chagas ◽  
Juliano Moro ◽  
...  
Keyword(s):  
South America ◽  
Magnetic Anomaly ◽  
Space Weather ◽  
Weather Prediction ◽  
Magnetic Data ◽  
Field Variation ◽  
Reference Field ◽  
The South ◽  
Data Set ◽  
Dip Angle

Abstract In the present work, we evaluate the accuracy of the Solar Quiet Reference Field (SQRF) model for estimating and predicting the geomagnetic solar quiet (Sq) daily field variation in the South America Magnetic Anomaly (SAMA) region. This model is based on the data set of fluxgate magnetometers from 12 magnetic stations of the Embrace Magnetometer Network (Embrace MagNet) from 2010 to 2018. The model predicts the monthly average horizontal field of the geomagnetic quiet (Sq-H) daily variation solving a set of equations for the specified geographic coordinates in terms of the solar cycle activity, the day of the year, and the universal time. We carried out two comparisons between the prediction and observational data of the Sq-H field. The first part attempts to evaluate the accuracy for estimating the Sq-H field over Medianeira (MED, 25.30°S, 54.11°W, dip angle: -33.45°) by using linear interpolation on the SQRF coefficients and compared it with the data collected from April to December in 2018. It worth mentioning that none of the datasets collected at MED is part of the dataset used to build the SQRF model, hence the need to do interpolation. The second part of the analysis attempts to evaluate the accuracy for predicting the quiet daily field variation over Cachoeira Paulista (CXP, 22.70°S, 45.01°W, dip angle: -38.48°). The dataset collected at CXP prior to the period analyzed in the present work is part of the dataset used to build the SQRF model. Thus, the accuracy of the prediction is tested using magnetic data outside the time interval considered in the model. The results of the prediction for both locations show that the outputs from this empirical model present a good agreement with the Sq-H field obtained from the magnetic field data. The accuracy of the SQRF model (high correlation, r>0.9) provides a high potential for estimating and predicting geomagnetic quiet daily field variation for space weather applications, improving the scientific insight and capability of space weather prediction centers to predict the variability of the regular solar quiet field variation as reference conditions, which may include areas with no measurements.

scholarly journals 3D Modeling and Tectonic Interpretation of the Erzincan Basin (Turkey) using Potential Field Data

2019 ◽  
Vol 23 (1) ◽  
pp. 57-66
Author(s):  
Ömer Lütfü Aydın ◽  
Ozcan Bektas ◽  
Aydın Büyüksaraç ◽  
Hüseyin Yılmaz
Keyword(s):  
Tilt Angle ◽  
Gravity Data ◽  
Analytical Signal ◽  
Geological Structure ◽  
Three Dimensions ◽  
Average Thickness ◽  
Horizontal Derivative ◽  
Surface Geology ◽  
Total Horizontal Derivative ◽  
Surface Observations

Erzincan Basin was investigated using gravity data within the scope of this study. It is also aimed to reveal the discontinuities in the work area as well as the buried discontinuities. Boundary determination filters and analysis of the structure of the data and its connection are revealed and clear information is obtained. Gravity anomalies were applied with an upward continuation method for 0.25, 0.50, 0.75 and 1 km levels. Total Horizontal Derivative (THD) filter, Analytical Signal (AS) filter, Tilt Angle Derivative (Tilt) filter, Total Horizontal Derivative (THDR) filter, Theta Angle Derivative (Cos ɵ) filter, Hyperbolic Tilt Angle Derivative (HTAD) were applied to upward continued data. The discontinuities in the region and the boundaries of the geological structure were revealed. Tilt and Theta Angle derivatives yield the best results from the applied derivative based filters. The obtained data were compared with the existing surface geology and the compatibility between the formations was checked. New discontinuities were found in addition to the discontinuities determined from surface observations in the light of the obtained results. Erzincan Basin was modeled in three dimensions using gravity data of the study area. As a result of modeling, Erzincan Basin has been determined to have an average thickness of 7 km.Total Horizontal Derivative (THD) filter, Analytical Signal (AS) filter, Tilt Angle Derivative (TAd) filter, Total Horizontal Derivative (THDR) filter, Teta Angle Derivative (Cos ɵ) filter, Hyperbolic Tilt Angle Derivative (HTAD) were applied to upward continued data. The discontinuities in the region and the boundaries of the geological structure were revealed. Tilt and Theta angle derivatives yield the best results from the applied derivative based filters. The obtained data were compared with the existing surface geology and the compatibility between the formations was checked. New discontinuities were found in addition to the discontinuities determined from surface observations in the light of the obtained results. Erzincan basin is modeled in three dimensions using gravity data of the study area. As a result of modeling, Erzincan Basin has been determined to have an average thickness of 7 km.

scholarly journals Evaluation of the Solar Quiet Reference Field (SQRF) model for space weather applications in the South America Magnetic Anomaly

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Sony Su Chen ◽  
Clezio Marcos Denardini ◽  
Láysa Cristina Araujo Resende ◽  
Ronan Arraes Jardim Chagas ◽  
Juliano Moro ◽  
...  
Keyword(s):  
South America ◽  
Magnetic Anomaly ◽  
Space Weather ◽  
Weather Prediction ◽  
Magnetic Data ◽  
Field Variation ◽  
Reference Field ◽  
The South ◽  
Data Set ◽  
Dip Angle

AbstractIn the present work, we evaluate the accuracy of the Solar Quiet Reference Field (SQRF) model for estimating and predicting the geomagnetic solar quiet (Sq) daily field variation in the South America Magnetic Anomaly (SAMA) region. This model is based on the data set of fluxgate magnetometers from 12 magnetic stations of the Embrace Magnetometer Network (Embrace MagNet) from 2010 to 2018. The model predicts the monthly average horizontal field of the geomagnetic quiet (Sq-H) daily variation solving a set of equations for the specified geographic coordinates in terms of the solar cycle activity, the day of the year, and the universal time. We carried out two comparisons between the prediction and observational data of the Sq-H field. The first part attempts to evaluate the accuracy for estimating the Sq-H field over Medianeira (MED, 25.30° S, 54.11° W, dip angle: − 33.45°) by using linear interpolation on the SQRF coefficients and comparing it with the data collected from April to December in 2018. None of the datasets collected at MED is part of the dataset used to build the SQRF model. The second part of the analysis attempts to evaluate the accuracy for predicting the quiet daily field variation over Cachoeira Paulista (CXP, 22.70° S, 45.01° W, dip angle: − 38.48°). The dataset collected at CXP before the period analyzed in the present work is part of the dataset used to build the SQRF model. Thus, the prediction accuracy is tested using magnetic data outside the time interval considered in the model. The prediction results for both locations show that this empirical model’s outputs present a good agreement with the Sq-H field obtained from the ground-based magnetometer measurements. The accuracy of the SQRF model (high correlation, r > 0.9) indicates a high potential for estimating and predicting geomagnetic quiet daily field variation. Concerning space weather applications, the model improves the scientific insight and capability of space weather prediction centers to predict the variability of the regular solar quiet field variation as reference conditions, which may include areas with no measurements.

ESTIMATION OF SOURCE PARAMETERS IN IBADAN, SOUTH – WESTERN NIGERIA USING DIGITIZED AEROMAGNETIC DATA

2018 ◽  
Vol 14 (2) ◽  
pp. 15-28
Author(s):  
A A ALABI ◽  
O OLOWOFELA
Keyword(s):  
Magnetic Susceptibility ◽  
Source Parameters ◽  
Granite Gneiss ◽  
Geological Structure ◽  
Magnetic Data ◽  
Susceptibility Map ◽  
Rock Types ◽  
Upward Continuation ◽  
Magnetic Basement ◽  
Local Wavenumber

Airborne magnetic data covering geographical latitudes of 7000‟N to 7030‟N and longitudes of 3 30′E to 4 00′E within Ibadan area were obtained from Nigeria Geology Survey Agency. The data were ana-lyzed to map the sub surface structure and the source parameters were deduced from the quantitative and qualitative interpretation of magnetic data. The upward continuation technique was used to de-emphasize short – wavelength anomaly while the depth to magnetic sources in the area was deter-mined using local wavenumber technique, the analytic signal was also employed to obtain the depths of the magnetic basement. Analysis involving the local wavenumber, upward continuation and appar-ent magnetic susceptibility techniques significantly improves the interpretation of magnetic data in terms of delineating the geological structure, source parameter and magnetic susceptibility within Iba-dan area.. These depth ranges from 0.607km to 2.48km. The apparent susceptibility map at the cut-off wavelength of 50 m ranges from -0.00012 to 0.00079 which agree with the susceptibility value of some rock types; granite gneiss, migmatite biotite gneiss, biotite muscovite granite, hornblende granite, quartz and schists. The result of the local wavenumber suggests variation along the profiles in the surface of magnetic basement across the study area.

scholarly journals PEMODELAN BAWAH PERMUKAAN MANIFESTASI MINERAL DENGAN METODE GEOMAGNETIK DAERAH PACITAN JAWA TIMUR

KURVATEK ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 25-33
Author(s):  
Fatimah Fatimah
Keyword(s):  
Image Data ◽  
Geological Structure ◽  
Magnetic Data ◽  
Magnetic Intensity ◽  
Magmatic Arc ◽  
The North ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Extensional Structure ◽  
Anomaly Map

Tulakan Subdistrict, Pacitan Regency, East Java Province. This area is part of the Southern Mountain Zone of East Java, which is the Sunda-Banda magmatic arc of Oligo-Miocene age, where there are alterations and indications of valuable ore minerals. Field magnetic data is taken in an area of 1 x 1 km, with the looping method on the grid trajectory within 200 x 100 m. Then, magnetic data correction and data processing were carried out with Oasis Montaj. From the magnetic anomaly map, the value of high magnetic intensity in the southern part is fresh (intrusive) andesit-dasitic rock as host rock which causes alteration, in the middle has a low magnetic intensity value which is in the direction of the relatively NE-SW river direction, whereas in the north with high intensity is fresh andesite lava. From the image data, it can be seen that the straightness pattern of the geological structure which is dominated by the extensional structure with the direction of NE-SW and E-W is the main trap of epithermal veins carrying ore mineralization mainly Cu, Pb in the study area.

scholarly journals Estimating Effectiveness of Some Methods for Detecting Edge of Potential Field Sources

2020 ◽  
Vol 36 (4) ◽  
Author(s):  
Pham Thanh Luan ◽  
Le Thi Sang ◽  
Vu Duc Minh ◽  
Ngo Thi To Nhu ◽  
Do Duc Thanh ◽  
...  
Keyword(s):  
Gravity Anomaly ◽  
Tilt Angle ◽  
Northeast China ◽  
Signal Amplitude ◽  
Analytic Signal ◽  
Detection Methods ◽  
Magnetic Data ◽  
Horizontal Gradient ◽  
North Vietnam ◽  
Gradient Amplitude

This paper presents a comparative study of effectiveness of edge detection methods such as total horizontal gradient, analytic signal amplitude, tilt angle, gradient amplitude of tilt angle, theta map, horizontal tilt angle, tilt angle of total horizontal gradient, tilt angle of analytic signal, improved theta map, and total horizontal gradient of improved tilt angle. The effectiveness of each method was estimated on synthetic magnetic data and synthetic gravity anomaly data with and without noise. The obtained results show that the tilt angle of gradient amplitude can detect all the edges more clearly and precisely. The applicability of each method is demonstrated on the aeromagnetic anomaly data from the Zhurihe region of Northeast China, and Bouguer gravity anomaly data from a region of North Vietnam. The results computed by the tilt angle of horizontal gradient were also in accord with the geologic structures of the areas.

scholarly journals Combination of Tilt-Angle and Euler Deconvolution Approaches to Determine Structural Features from Aeromagnetic Data Modeling over Akonolinga-Loum Area (Centre-East, Cameroon)

2017 ◽  
Vol 08 (07) ◽  
pp. 925-947 ◽  
Author(s):  
Justine Yandjimain ◽  
Théophile Ndougsa-Mbarga ◽  
Arsène Meying ◽  
Marcelin Bikoro Bi-Alou ◽  
Paul Claude Ngoumou ◽  
...  
Keyword(s):  
Tilt Angle ◽  
Data Modeling ◽  
Structural Features ◽  
Aeromagnetic Data ◽  
Euler Deconvolution

scholarly journals PEMETAAN SEBARAN BATUAN PENYUSUN PAGAR CANDI DI SITUS CANDI LOSARI DUSUN LOSARI, DESA SALAM, KECAMATAN SALAM, KABUPATEN MAGELANG BERDASARKAN METODE MAGNETIK

2013 ◽  
Vol 33 (1) ◽  
pp. 121-131
Author(s):  
Novi Dwi Ariani ◽  
Thaqibul Fikri Niyartama ◽  
Nugroho Budi Wibowo
Keyword(s):  
Magnetic Field ◽  
Field Data ◽  
Daily Variation ◽  
Local Magnetic Field ◽  
Magnetic Data ◽  
Reference Field ◽  
Magnetic Pole ◽  
Local Anomaly ◽  
Anomaly Pattern ◽  
Anomaly Map

Mapping geophysics research was conducted by geomagnetic method to know anomaly pattern of magnetic pole and to know distribution location and depth of temple gate composing stone in Losari Temple Site by using magnetic data. Data collection used Proton Precessions Magnetometer (PPM) G-856AX by area width of 88 km x 40 km and measurement space of 3 meter used looping method. Field data was corrected by daily variation and IGRF (International Geomagnetics Reference Field) correction and then reduction to pole. The slice modeling was conducted on local anomaly map on height of 6 meter. The result of the local magnetic field anomalies incision then interpolated to get an idea of the spread and depth of rocks making up the fence Losari temple. Local anomaly map shows that anomaly position lies in southwest, southeast, and northeast from main temple. Based from interpolated distribution of magnetic pole anomaly is dominated in depth of 2 meter to 4 meter. 

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