Volume 5, Issue 3

Superimposed Decomposition of Wavelet Analysis for Seismological Investigations: Validation on GPS Stations Displacements in Central Alaska (2008-2012)
Special Issue
The comprehensive study of seismic waves is very important in order to understand the complex dynamic processes of the Earth’s interior as well as its signals emerged to the physical surface. In the last three decades, observational Global Positing System (GPS) products through determining the displacements of ground GPS station in horizontal and vertical directions have widely been applied to infer the tectonic stress regimes generated by the subsurface processes ranging from the local fault systems to the huge tectonic plate movements. However, the complex patterns generated during such movements are not always easy to interpret. Therefore, it is necessary to develop new approaches by modifying the previous strategies and improve the current methodologies to understand better such sudden crustal movements. In this paper, we employed 5 years GPS stations displacements data from January 1, 2008 to December 31, 2012 in the seismically active central Alaska area, in order to get the average daily and annual velocities of the GPS stations. Then, vector summation for horizontal and vertical velocities has been applied to yield the total velocities of GPS stations displacements. Moreover, we applied the Cross-Correlation Functions (CCFs) analysis to recognize the significant and homogenous displacements among the total displacements of GPS stations located in this region to be employed in next step for the superimposed decomposition of wavelet analysis at level number 1 and 2. Finally, the normal probability histograms related to the accuracy of each analysis are calculated and presented in details. The results show a very good agreement between the CCFs reorganizations, proposed wavelet decomposition methodology, and simultaneous earthquakes regimes occurred in central Alaska from 2008 to 2012 year.
Journal of Geosciences and Geomatics. 2017, 5(3), 147-166. DOI: 10.12691/jgg-5-3-6
Pub. Date: July 17, 2017
14791 Views2170 Downloads
Uranium Mineralization in Gubrunde Horst, Upper Benue Trough, North-East, Nigeria
Original Research
The aim of this work is to undertake a study on the occurrence of uranium bearing rocks in the area and infer the source, mechanism of migration and structures or rock type hosting uranium mineralization. This was achieved by an integration of radiation point count, petrographic studies and structural analysis. This is necessary because the Gubrunde uranium occurrence is one of the several known trace to extensive mineralization in North East Nigeria that have been least studied even in the midst of the increasing quest for clean and cheap energy. Moreso, the occurrence of uranium in the area is suspected to be associated with several health implications to the human population. The area has favorable geological environment and conditions for uranium mineralization. Field relationship shows that structurally and tectonically controlled Cretaceous continental sandstones are underlain by acidic granites of the Precambrian basement complex. These are in some places, intruded by much younger volcanic which forms traps for uraniferous solution being transported by hydrothermal fluid in structural conduits. Structural analysis of structures in the area showed a NNE-SSW deformational trend. Samples of rocks from the entire area shows dark to brown opaque minerals suspected to be uranium (Uraninite or Coffinite). Radiation point count confirms the occurrence of radiation ranging from 7.5×104 µCi -6.40×105 µCi concentration levels. There is structural and geochemical control to mineralization in the area. Radiation levels at some points were noted to be above human tolerable levels.
Journal of Geosciences and Geomatics. 2017, 5(3), 136-146. DOI: 10.12691/jgg-5-3-5
Pub. Date: July 15, 2017
15601 Views2658 Downloads
The Role of Human Activities in Streambank Stability: Lower Sakarya River (NW Turkey)
Original Research
The main objective of this study is to determine historic and current human impacts on streambank stability in Lower Sakarya River. Remote sensing and Geographical Information System techniques with conjunction field works were performed to identify the impact of human alteration on streambank stability in the riverine environment of the eastern portion of Sakarya province. LULC (land use/cover) and historical streambank changes were analyzed from Landsat 1-5 Multispectral Scanner (MSS), Landsat-7 Enhanced Thematic Mapper Plus (ETM+), and Google Earth images between 1995 and 2016. As results, a significant LULC changes have been observed along the buffered zone due to population growth. Recently, change in LULC type from agricultural to urban usage has changed river equilibrium. The stream channel also became more stable and straight as man-made modifications including a hydropower (HES) dam constructed in 2010, which primarily reduced flood frequency, water velocity, stream power, shear stress on sediment particles temporarily deposited along the streambank. After the year of 2010, downstream portion of the dam had experienced narrowing and expanding mid-channel bars. Moreover, the channel has been slightly moved towards east especially along urbanized and sinuous courses. The streambank displacement ranged from 2.9 m to 36 m in the region. Instream mining activities and bridge constructions in the region also disturb active streambanks, which raise a concern about instability of streambank and potential damage to infrastructures. Such studies are extremely important for understanding basic mechanisms of streambank evolution for further river restoration practices.
Journal of Geosciences and Geomatics. 2017, 5(3), 130-135. DOI: 10.12691/jgg-5-3-4
Pub. Date: June 15, 2017
15479 Views3188 Downloads
The Pan-African Biotite-Muscovite Granite and Amphibole-Biotite Granite of Doua (Central Cameroon): Zircon Features, LA-MC-ICP-MS U-Pb Dating and Implication on Their Tectonic Setting
Original Research
The Doua area belongs to the Adamawa-Yadé domain (AYD) of the Central African Fold Belt (CAFB) in Cameroon. It is crossed by the Central Cameroonian Shear Zone (CCSZ). The purpose of this research is to determine the tectonic setting of granites of the studied area, based on their petrography, zircons feature and their ages. Petrographicaly, the Doua area is made up of plutonic rocks hosted in an ortho or paraderivative metamorphic basement. Amphibole-biotite granite (ABG) and biotite-muscovite granite form hills and crop out on the hill side, as flagstones in the valley or river bed, and as huge blocks. Amphibole-biotite granite is granular in texture and made up of amphibole, biotite, feldspar, accessory minerals (Sphene, zircon, and apatite) and secondary minerals (sericite). Biotite-muscovite granite (BMG) is granular to granular porphyritic in texture, made up of biotite, muscovite, plagioclase, K-feldspar, quartz, accessory minerals (zircon, opaques minerals) and secondary minerals (chlorite, sericite). ABG show elongated zircon grains with well-developed magmatic oscillatory zonation. LA-ICP-MS U-Pb data from these zircons define a concordia age of 607 ± 3 Ma and considered as crystallization age of the granite. BMG shows zircon with various shape and various internal structures (oscillatory zonation, sector zonation, blurred oscillatory zonation …) which are divided into two sets. The first set regarded as xenocryst from Paleoproterozoic granitoids emplaced at 2126 ±36 Ma or from sediments which detritus comes from such granitoids. The second set of zircons shows effects of recent lead lost and a subconcordant U-Pb age of 646 ± 39 Ma . ABG was emplaced during the D3 deformational phase, date at 607 ± 3 Ma , while BMG was trigger because of syn-D1 activity of the CCSZ at 647 ±46 Ma in association with the collisional process.
Journal of Geosciences and Geomatics. 2017, 5(3), 119-129. DOI: 10.12691/jgg-5-3-3
Pub. Date: June 09, 2017
17452 Views3941 Downloads
Performance Evaluation of Multivariate Adaptive Regression Splines (MARS) and Multiple Linear Regression (MLR) for Forward Conversion of Geodetic Coordinates (ϕ, λ, h) to Cartesian Coordinates (X, Y, Z)
Original Research
In Ghana’s local Geodetic Reference Network, the standard forward transformation equation has played a major role in coordinate transformation between World Geodetic System 1984 (WGS84) and local geodetic datum. Thus, it is an initial step in forward conversion of geodetic coordinates (ϕ, λ, h) to Cartesian coordinates (X, Y, Z) in transformation from global to local datum and vice versa. Several studies in the recent decades have been conducted on converting Cartesian coordinates to geodetic coordinates (reverse procedure) through the utilisation of iterative, approximate, closed form, vector-based and computational intelligence algorithms. However, based on the existing literature covered pertaining to this present study, it was found that the existing knowledge do not fully adhere to the issue of evaluating alternative techniques in the case of the forward conversion. Hence, the aim of this present study was to explore the coordinate conversion performance of the Multivariate Adaptive Regression Splines (MARS) and Multiple Linear Regression (MLR). The performance of each model was assessed based on statistical indicators of Mean Square Error (MSE), Root Mean Square Error (RMSE), Mean Bias Error (MBE), Mean Absolute Error (MAE), Standard Deviation (SD), Noise to Signal Ratio (NSR), Correlation Coefficient (R), and Correlation of Determination (R2). The statistical findings revealed that the MARS and MLR offered satisfactory prediction of Cartesian coordinates. However, the MLR compared to MARS showed better stability and more accurate prediction results. From the results of this present study, the main conclusion drawn is that, MLR provides a promising alternative in the forward conversion of geodetic coordinates into Cartesian coordinates. Therefore, the capability of MLR as a powerful tool for solving majority of function approximation problems in mathematical geodesy has been demonstrated in this present study.
Journal of Geosciences and Geomatics. 2017, 5(3), 109-118. DOI: 10.12691/jgg-5-3-2
Pub. Date: May 03, 2017
17347 Views3606 Downloads
Appraisal of Methods for Estimating Orthometric Heights – A Case Study in a Mine
Original Research
The concept of orthometric heights system determination plays a major key role in geodesy, and it has broad applications in various fields and activities. In geodesy, one significant quantity is the orthometric height, the height above or below the geoid along the gravity plumbline. Conventionally, the orthometric height is determined by gravimetry and levelling techniques. However, the aforementioned techniques has its own demerits. Thus, the error is accumulated with the increase of the propagation measurement line, it is difficult to convert two separated points which is located in two continents or islands separated by sea. These techniques are tedious, time consuming and expensive. In order to resolve this challenge, many researchers resort to various techniques and approaches of obtaining orthometric heights for an area using various mathematical models. It is in this quest that, this study seek to estimate orthometric heights of a mine by utilizing plausible alternative techniques based on artificial neural networks (ANN), multivariate adaptive regression splines (MARS), polynomial regression models and multiple linear regression (MLR). The working efficiency and performance of each model has been assessed based on statistical indicators of Mean (M), Mean Square Error (MSE), Root Mean Square Error (RMSE), Mean Bias Error (MBE), Mean Absolute Error (MAE), Standard Deviation (SD), Correlation coefficient (R), Correction of determination (R2), and Signal to Noise Ratio (SNR). The statistical findings reveal that all the models produce satisfactory results in estimating the orthometric heights in the mine. MARS and ANN models compare to the MLR and polynomial models achieved higher results in terms of accuracy with mean and standard deviation of -0.000001888 m, +2.24736 m, and +0.005835 m and 0.095063 m respectively. This study will create the opportunity for geospatial practitioners to recognize the significant of ANN, MARS, MLR, and Polynomial model in solving some of the problems in geoscientific community.
Journal of Geosciences and Geomatics. 2017, 5(3), 96-108. DOI: 10.12691/jgg-5-3-1
Pub. Date: May 03, 2017
14726 Views2780 Downloads