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Journal International Journal of Geosciences

924 articles
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U. Z. Magawata, D. S. Bonde, B. U. Abdullahi, Basiru Qudus, M. N. Yahaya
International Journal of Geosciences, Volume 11, pp 25-36; doi:10.4236/ijg.2020.112003

Abstract:Very low frequency (VLF-EM) was used to assess variations in overburden composition, bedrock lithology and the hidden Sedimentary structures within the foundation of Shagari Dam of the sedimentary basin of Northwestern Nigeria. Four VLF-electromagnetic (EM) traverses were occupied at 10 m in-tervals. The VLF normal and filtered real component irregularities identify major geological interfaces suspected to be faults/fractured zones. The points of crossover between the real and imaginary components delineate the fractured zones, which were identified as areas of possible seepage (sloughing and piping). The fractured zones are suspected to be present at all traverses. In total, 38 fractured zones were identified along the dam embankment and canal site, while 17 major fractures occurrence dippers along the Traverses at a point, Traverse 1 (F3, F4, F5, F7, F10, F11), Traverse 2 (F12, F13, F21, F22), Traverse 3 (F23, F24, F29) and Traverse 4 (F32, F33, F34, F38), and coincide with cross over point at 4 traverses. These seepage zones cause heterogeneity in the sub-surface structure that could be prime to dam failure which in turn leads to the flooding, decreases in irrigations activities of the peoples leaving around the dam and loss of several hundreds of life when care not taken. The result of the study suggests that VLF is suitable for observing seepages in embankment dams.
U. Z. Magawata, Ibrahim Mohammed, B. A. Ojulari, A. I. Augie, Salisu Musa
International Journal of Geosciences, Volume 11, pp 1-13; doi:10.4236/ijg.2020.111001

Abstract:An integrated geophysical investigation using very low frequency electro-magnetic (VLF-EM) and electrical resistivity methods using (VES) technique has been carried out for investigation of possible causes of dam failure in Kali, Aliero Northwestern Nigeria. A total of Three 3 (VLF-EM) traverses and Ten 10 vertical electrical soundings (VES) techniques have been carried out to identify the fracture zones, seepage and possible threat that lead to the collapse of the dam. The interpretation of VLF-EM data is carried out qualitatively using Fraser and Karous-Hjelt filters and the interpretation of sounding data is done using IPI2 win software. VLF-EM data signifies the exact fracture zones founded on higher values of relative current density that coincide to the subsurface fracture. The survey was conducted on an interval of 10 m interval along traverses at South-North direction ranging from 620 - 640 m in length. The plot of filtered real and filtered imaginary identified noticeable fracture zone close to the surface which was later further delineated by (VES) technique. VES soundings were carried out at locations of prominent VLF anomalies presumably typical of basement fracture using AB/2 of 80 m. Results interpreted show layers thickness and their corresponding resistivity, top soil (0.5 m to 3.45 m, 51.9 Ωm to 318 Ωm), underlain by clay to confined clay (4.56 m to 54 m, 7.88 Ωm to 60.2 Ωm) which is underlain by fractured/fresh basement (5.76 m to 73.9 m, 40.3 Ωm to 197 Ωm). The overburden materials underlain are far away to subsurface (bed rock) in most of the area to support the dam. The clay materials which could serve as conduit, exist within the shallow overburden which was not excavated during the construction. Therefore it was concluded that the dam cannot retain its strength to oppose the dam against collapse.
Barry Mamadou Saliou, Xinwu Huang
International Journal of Geosciences, Volume 11, pp 15-24; doi:10.4236/ijg.2020.112002

Abstract:Exploration and prospecting for mineral resources deposits are perceived to not be an easy process due to big deposits being discovered in early times. Numerous gold prospecting methods have been used in gold prospecting. The aim of this research is to critically analyze both traditional and modern gold prospecting methods that are being used in gold exploration. The research objective is to critically evaluate the numerous studies that focus on gold prospecting methods in an effort to provide an effective analysis of gold prospecting methods. In doing so, the study has used a qualitative method to review the existing literature. The study reviews academic journals and articles, books, and periodicals which were published between 2010 and 2019. This study has achieved to critically analyze both traditional and modern gold prospecting methods. The study finds out that the traditional gold prospecting methods include gold panning and dry washing. Additionally, the current gold prospecting methods include biological prospecting, geochemical prospecting and geophysical prospecting methods.
Kaboré M’Bi, Zerbo Jean Louis, Zoundi Christian, Ouattara Frédéric
International Journal of Geosciences, Volume 10, pp 833-844; doi:10.4236/ijg.2019.1010047

Abstract:In this paper we report on the foF2 variabilities for two equatorial regions (Ouagadougou: Lat. 12.4°N; Long. 358.5°E, Dip. 1.43°S; and Manila: Lat. 14°36'15.12''N; Long. 120°58'55.92''E; Dip. 0.6°S) during solar cycles 20 and 21 minima and maxima phases. Many previous works have argued on the diurnal and seasonal variation of foF2 for different solar events conditions for latitudinal position. But there are few investigations for Africa equatorial region longitudinal variation. The present paper’s goal is to outline possible similarity in foF2 behavior between variations for better understanding of physical process lead to some observed phenomenon in Asia-Africa equatorial sector. The F-layer critical frequency (foF2) data observed from the two equatorial ionosonde stations have been used for the present comparative study. The results show significant similarity between the critical frequency (foF2) seasonal variations over the time intervals 1976-1996. During day-time measured data from Manila station are higher than those from Ouagadougou station. That may lie in that Manila is closer to equatorial ionization crest region. During solar minimum phase, the longitudinal variation of foF2 shows two crossing points (11:00 UT and 22:00 UT) between the foF2 profiles form the two stations for all seasons regardless of the solar cycle. However during intense solar activity condition, the number of crossing-point between measured data from Manila and Ouagadougou stations varies by seasons and solar cycle. This phenomenon may be due to the compilations of severe activities (storms, coronal mass ejection, heliosheet fluctuations) during the solar maximum phases.
Fikre Zerfu, Abdurehman Mektel, Biniyam Bogale
International Journal of Geosciences, Volume 10, pp 811-832; doi:10.4236/ijg.2019.109046

Abstract:Drastic changes have occurred in Siti zone rangeland over nearly the last three decades, due to rapid land conversion dynamics in the area. In the zone, the land-use change over time and space and temporal trends rangeland condition have never been studied. This study analyzed land use and land cover (LULC) change dynamics since the 1980s. Three dates, 1985, 2001 and 2017, Landsat images were used for classification and analysis of the various LULC. The three images were geo-referenced, re-sampled and processed for classification, using the maximum likelihood classifier algorithm. Moreover, field observations and information from local people were used for triangulation to patterns LULC dynamics. From 1985 to 2017, the general trend observed in the land use/cover change in the rangeland resources in the study districts implies a loss of grassland cover was compensated by an increase in cultivated areas, settlement and shrub/bush land cover. Moreover, the encroachments of invasive plant, Prosopis, settlement and the promotion of cultivation to pastoral way of livelihood have exacerbated the decline of rangeland cover. The study findings have shown important changes in the LULC patterns in the north-eastern Somali rangelands of eastern Ethiopia. These trends are certainly the characteristics of a pastoral way of life turn to settlement. This suggests that major changes in the socio-ecological driving forces affecting landscape dynamics have occurred in the last three decades or so.
Felix Ike, Chinyere Ruth Ottah
International Journal of Geosciences, Volume 10, pp 801-810; doi:10.4236/ijg.2019.109045

Abstract:Marshlands are important ecosystem for living organisms. The Southern Iraqi Marshland is the central habitat for freshwater fish, provides habitat for important populations of wildlife and serves as a source of income for native economies through reed harvesting. Studies have shown that variability in climate and human-induced factors affects the spatial dynamics of marsh ecosystems. This study assessed wetland changes in the Southern Iraqi Marshlands using Remotely Sensed Data from 1986 to 2019 using Landsat satellite imagery for four epochs: 1986, 2000, 2010 and 2019. To achieve this, thirty (30) pixels were obtained in selected land cover theme and their signatures were merged into one class. Furthermore, the selected pixels were recoded and merged into ten (10) land cover classes. The multi-layer classes created were shallow water, deep water, dense marsh, medium marsh, sparse marsh, dense vegetation, medium vegetation, sparse vegetation, dry soil and wet soil. The areal extents of the land cover types were calculated for 1986, 2000, 2010 and 2019. Normalized Difference Vegetation Index (NDVI) differencing was also carried in order to highlight trends in vegetation from 1986 to 2019. The study correlated historical trends of human activities as a central factor in the degradation of marshland (by 16.25%) from 1986 to 2000. However, by the year 2000 to 2010, there was an 11.36% increase in the total marshland area, which remained almost unchanged between 2010 and 2019. In 1986, NDVI was relatively stable at 0.73 in the Al-Hammar and Al-Hwaizeh Marsh. However, by 2000, the areas of dense vegetation cover reduced drastically by over 90%. In 2010, the NDVI index indicated trends of increasing water body and an outward cluster of healthier vegetation continuing to 2019.
Nils-Axel Mörner
International Journal of Geosciences, Volume 10, pp 745-757; doi:10.4236/ijg.2019.107042

Majed Ibrahim, Fatima Ghanem, Afnan Al-Salameen, Abdallah Al-Fawwaz
International Journal of Geosciences, Volume 10, pp 576-588; doi:10.4236/ijg.2019.105033

Abstract:Soil organic matter (SOM) is an important term to realize soil productivity and quality that is extremely influential on soil physical, chemical and biological processes; SOM is one of the key soil properties controlling nutrient budgets in agricultural production systems and is an important index of soil productivity. Remote sensing (RS) and Geographic Information System (GIS) techniques were used to assess organic matter in soil and determine the relationship between measures SOM in field and digital data to calculate or obtain the correlation coefficients applied to evaluate the strength and direction of the linear relationships. In this study Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI) and Bare Soil Index (BSI) were used. The results show that the relationship between vegetation indices (NDVI, SAVI) and SOM in whole study area was (R2 = 0.19, p 2 = 0.01, p 2 = 0.13, p 2 = 0.11, p < 0.05), soil organic carbon increases with increasing NDVI and decreasing BSI. NDVI, SAVI and BSI were considered a useful index to detect the spatial distribution of SOM concentrations and mapping using remote sensing data.
Michael G. Noppe
International Journal of Geosciences, Volume 10, pp 785-799; doi:10.4236/ijg.2019.108044

Abstract:The article describes a project proposed to determine the epicenter of a future short-focus earthquake tens of hours before and to reduce the magnitude of an impending catastrophic earthquake. It focuses on developing a physical model to determine the conditions necessary for the start of an earthquake, for a method based on the registration of flows of mercury vapor in the gas rising from the Earth. This model gives an explanation of why an earthquake precursor appears so early (such a long period of time can range from a few to hundreds of hours). Normally, the characteristic times of an earthquake precursor for seismic methods are tens of seconds. The project is based on the physical and mathematical models of an earthquake. The derived formula for the time of the precursor of a future earthquake allows us to explain and to describe the time increase for the precursor, depending on the magnitude of the earthquake. The method of reducing the magnitude of an impending catastrophic earthquake is based on the proposed physical model of the onset of an earthquake and is implemented by the action of a vibration source in the region of the detected earthquake epicenter. The proposed system should save citizens, lives from future short-focus earthquakes.
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