Earth and Planetary Science

Journal Information
EISSN : 2810-9732
Published by: Nan Yang Academy of Sciences Pte Ltd (10.36956)
Total articles ≅ 5
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Anatoly R. Ischuk, Conrad Lindholm, Zuhra G. Ilyasova, Shohruh Murodkulov
Earth and Planetary Science, Volume 1; https://doi.org/10.36956/eps.v1i1.510

Abstract:
In current Probabilistic Seismic Hazard Analysis we analyzed an area and fault models. Shallow crust and deep earthquakes are occurred in the area of Tajikistan, and used two area models for shallow earthquakes and one area model for the deep earthquakes. Additionally, we used so called “Woo’s model” or “point model” which is based on the past seismicity more directly. Six active fault databases for Central Asia and specifically for Tajikistan were used to create the fault model.Software CRISIS2015 and recent Ground Motion Prediction Equations were used in the computation. A grid with 0.1 degree of latitude and 0.1 degree of longitude covered the study area, was created for calculations, and for each 9744 grid points we calculated the spectral accelerations from 0.01 s (PGA) to 3.0s, and for 5 exceedance probabilities in 50 years.For easy application of the results in seismic design, all calculations were made for three values of Vs30, corresponding to 3 categories of the soils in the existing Seismic Design Code in Tajikistan.Special 15 Excel sheets were created for engineers and designers to easy construct the uniform hazard spectra for three types of soil conditions for needed points and exceedance probabilities.
Faramarz Abazari, Hossein Jalilifar, Mohammad Ali Riahi
Earth and Planetary Science, Volume 1; https://doi.org/10.36956/eps.v1i1.524

Abstract:
The instability of the wellbore has significant effects on drilling, causing delays in operations, increasing costs, and ultimately may result in the abandonment of wells. Nowadays, it is possible to stabilize a wellbore by changing the drilling mud composition. With the help of rock mechanics and knowledge of the mechanical properties of the formation, the optimal path for the drilling of the well and the window of the mud is determined. Several features of the formation are influential in wellbore design; knowing these features is necessary for designing optimal mud weight to ensure wellbore stability. In practice, analytical methods for the calculation of the optimal mud weight are more convenient than numerical ones because the latter needs information on many samples that are usually unknown at the commencement of the project. This research investigates the wellbore stability in the Kupal carbonate oil field using an analytical method with three rock strength criteria of Mogi-Coulomb, Mohr-Coulomb, and Hoek-Brown failure. We conclude that the Mogi-Coulomb criterion predicts a minimum drilling mud pressure and is more conservative. This is due to the use of its intermediate stress.
Francis Temgo Sopie, Victorine Ambassa Bela, Armel Zacharie Ekoa Bessa, Archange Duviol Tsanga, Patrice Roland Liyouck, Théophile Njanko, Gabriel Ngueutchoua
Earth and Planetary Science, Volume 1; https://doi.org/10.36956/eps.v1i1.525

Abstract:
Sandy sediments collected along the southern part of the Cameroonian coast have been analyzed geochemically by ICP MS methods to investigate the distribution characteristics, contamination levels and related ecological risks. In these sediments, the concentration (mg/kg) of selected elements are in order Fe > Mn > Cr > V > Th > Ni > U > Co. Indices of pollution such as index of geoaccumulation, where values of all elements in the sediments were < 0, except Th in the sediments station of Yoyo II, and Cr in sediment of all stations were Igeo > 0. Contamination factor shows that the station of Yoyo II has values of CF < 1, such as Fe, V, Ni and Co. while Uranium, Th and Mn values vary from 1 to 3 and 3 to 6, and for Cr values of CF > 6. However, Kribi and Campo stations show that all the elements have values of CF < 1, except Cr which has values of CF > 6. The degree of contamination values ranges between (9.48 – 37.13) for the station of Yoyo II, (8.84 – 17.62) for Kribi station, and (6.52 – 13.56) for Campo station. The pollution loading index values at all sampling stations are lower than 1. The potential ecological risk (Er and RI), indicates that this coastal area is a low risk region. Pearson correlation, cluster analysis and principal component analysis supported that heavy metals (Fe, Mn, Cr, V, Ni and Co) have common human influences while radionuclides (Th and U) have a natural source. The presence of human activities such as domestic waste, intensive farming and the processing of industrial products could be potential sources of anthropogenic environmental pollution, thereby threatening the environmental concerns of the entire study area.
Haidar Salim Anan
Earth and Planetary Science, Volume 1; https://doi.org/10.36956/eps.v1i1.511

Abstract:
Ninety-seven Campanian–Paleogene smaller agglutinated benthic foraminiferal species belong to thirty-five genera from ten countries in the Southern Tethys (Algeria, Egypt, Palestine, Jordan, Iraq, Qatar, UAE, Iran, Pakistan, India) have been studied. The modern taxonomical consideration of the species are used. Eighty-nine of the recorded species were previously noted in the literatures, while eight of them are believed here as new: Haplophragmoides iranica, Pseudogaudryinella iraqensis, Arenobulimina beitjebrinensis, A. jerusalemensis, Textulariella sinaensis, Dorothia iranica, Clavulinoides iranica, and Textularia salahii. Forty species of them are recorded from Egypt (about 41%), twenty seven from Pakistan (~28%), ten from UAE (~10.5%), six from Qatar (~ 6%), four from each of Algeria and Iran (~ 4 %), three from each of Jordan (~ 3%), two from each of Palestine and Iran (~2%), and only one from each of Iraq and India (~1%). Most of the Southern Tethyan recorded species are endemic to their original description, while five of them are also recorded in some Northern Tethyan countries (Spain, France, Italy, Hungary and Slovenia): Bathysiphon saidi, Haplophragmoides desertorum, Spiroplectinella esnaensis, Siphogaudryina africana and Textularia crookshanki. The Southern Tethyan assemblage indicate an open marine environment, which represents middle-outer neritic environment (100-200 m depth), and show s an affinity with Midway-Type Fauna 'MTF'' of the United States Gulf Coastal area.
Muhammad Jahangir Khan, Syeda Rida Fatima Bokhari, Umair Bin Nisar, Farhad Ali
Earth and Planetary Science, Volume 1; https://doi.org/10.36956/eps.v1i1.520

Abstract:
Availability of subsurface fresh water in coastal cities of the world is a growing problem due to sea level intrusion and less seepage. We have utilized an integrated data analysis in which conventional geophysical methods was used to collect primary data for the groundwater resources in Karachi and geospatial approaches were used to model the hydrogeological parameters. It was aimed to investigate geological/hydrogeological conditions of any aquifer system in the study area. The geophysical survey was conducted to acquire electrical resistivity data in the outskirts of Karachi. The geophysical survey was carried out at twenty-one stations by adopting vertical electrical sounding technique with schlumberger configuration. The field data was processed in an iterative process to improve the signal to noise ratio and obtain smooth field data curves for delineation of the aquifer. We have interpreted field data to model the geological information and determine the hydrogeophysical parameters of respective layers. These parameters including the number of layers, aquifer resistivity, aquifer lithology, aquifer thickness and depth to the aquifer, are determined at each field station. The acquired dataset of hydrogeophysical parameters was used to build a geospatial database. The multi-criteria analysis and decision-making process were utilized in GIS based program to model spatial distribution models of hydrogeophysical parameters. The results identified aquifer system in the depth ranging from 53.3 meter to 143.9 meter. The aquifer in the area are mostly sandstone having sufficient thickness which varies from northeast to south and southwest due to undulating topography of the area. The maximum potential of the groundwater is identified in the south which is suitable for water exploration because of low resistivity zone, high aquifer thickness, and flow of drainage network.
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