Seismo-stratigraphic and structural interpretation of seismic data of Titas gas field,Bengal basin,Bangladesh     

Md. Sultan-Ul-Islam  Md. Aminul Islam  Md. Hasan Latif  Md. Aftabuzzaman  Syed Mustafizur Rahman  Md. Ismail Molla  Mohamed Ragab Shalaby 《Journal of the Geological Society of India》2017,89(4):471-481

In the present study, seismic interpretation has been carried out over Titas structure of Bengal basin, Bangladesh to figure out its seismo-stratigraphic and structural behavior. Seven well marked reflecting horizons (R-01 to R-07) have been identified within the Neogene sedimentary sequences using 18 seismic sections and well log data. A new seismic stratigraphy of Neogene sequences has been proposed for the Titas structure ruling out the traditional lithostratigraphy. The studied structure has been divided into 3 megasequences (MS1, MS2 and MS3). Reflector R-01 and R-03 represent the tops of the megasequence 2 (MS2) and megasequence 1 (MS1) respectively. These well marked reflectors are correlated with the top of the traditional litho-groups called Tipam and Surma. Reflectors R-02 and R-04 represent acoustic impedance boundaries within MS2 and MS1 due to lithological gradation. However, R-02 and R-04 are not considered as sequence/ formation boundaries because geologically these are not well defined. Reflectors R-05, R-06 and R-07 represent top of the gasbearing zones A, B and C that belongs to MS1. All these interfaces or reflectors are anti-form with a central long crestal zone. It forms a north-south trending semi-domal sub-surface anticlinal structure having a semi-dome shaped closure. The structure is asymmetric with steeper eastern flank and gentler western flank. The crestal region is essentially plain with discontinuous reflection. The semidomal nature of the anticline is in contrast to the neighboring narrow anticlines. Structural pattern suggests its development in relation to the NE-SW trending stress field due to convergence of Indian plate with Burmese plate. Structures of the shallower and deeper reflectors are formed at different phases of structural development.  相似文献   

Application of the Artificial Neural Network and Neuro‐fuzzy System for Assessment of Groundwater Quality          下载免费PDF全文

Mahmoud Khaki  Ismail Yusoff  Nur Islami 《洁净——土壤、空气、水》2015,43(4):551-560

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The Distribution of Riparian Corridor Plants and the Relations to River Water Salinity along Perai River, Penang, Malaysia     

Johan Ismail  Mashhor Mansor 《湿地科学》2010,8(1)

Ecological surveys were carried out to investigate the distribution and characterization of riparian corridor plants along the Perai River,Penang,Malaysia from July 2007 to March 2008.Surveys were design to represent horizon-tal sections of the river starting from the river mouth towards the upper reaches for 20 km.A total of 84 species of plants from 30 families were recorded.They consisted of 28 species of standing plants(plants with height of more than 1 m)and 56 species of weedy plants(plants with heigh...  相似文献   

Estimation of the 2D crustal velocity structure in the Hidaka and Iburi Subprefectures, Hokkaido, Japan     

Ismail Husain Fathi  Kaoru Miyashita 《Arabian Journal of Geosciences》2009,2(3):235-239

Applying the iterative shooting/bisection technique for rapid forward modeling to the seismic explosion data, we could refine the crustal velocity structure model of the western part of the Hidaka collision zone, Hokkaido, Japan. We used only the precise P-wave first arrival data obtained by the Research Group for Explosion Seismology, which set up a 113.4-km-long profile in August 2000 along with 327 observation points and four shot points with TNT charges from 100 to 300 kg. We could estimate a two-dimensional inhomogeneous crustal velocity structure model with a velocity decrease in the eastern direction at a depth of 15.7 km, several portions of velocity reversals with depth and a low velocity anomaly proposed in previous studies. The root-mean-square of travel-time residuals was improved from 0.398 s for the previous structure model to 0.176 s for the present model with a reduction of 55.8%.  相似文献   

WATER QUALITY STUDIES IN MALAYSIAN DISUSED MAN MADE LAKES FOR SUITABILITY OF AN AQUACULTURE PROJECT     

Azma Hanim Ismail  Mashhor Mansor  Wan Maznah W O 《湿地科学》2005,3(4)

1INTRODUCTIONWater is an essential component of an eco-sys-tem.It sustains life on the earth.A community de-pends on water for its domestic,agricultural and in-dustrials needs.According to Ackefors,et al.(1994),the term water quality'in the context ofaqua…  相似文献   

In-situ investigation on real-time suspended sediment measurement techniques: Turbidimetry,acoustic attenuation,laser diffraction (LISST) and vibrating tube densimetry     

David Felix  Ismail Albayrak  Robert Michael Boes 《国际泥沙研究》2018,33(1):3-17

Real-time measurements of Suspended Sediment mass Concentration(SSC) and Particle Size Distribution(PSD) are of prime importance for the investigation and management of fine-sediment related processes in surface water systems and hydraulic schemes. In a field study at the waterway of the hydropower plant(HPP) Fieschertal in the Swiss Alps, the real-time measurement performance of the following techniques and instruments were assessed based on measurements in the sediment seasons of the years 2013 and 2014:(1) turbidimetry,(2) single-frequency acoustic attenuation using a standard acoustic discharge measurement(ADM) installation,(3) laser diffraction(Laser In-Situ Scattering and Transmissometry, LISST), and(4) vibrating tube densimetry using a Coriolis Flow and Density Meter(CFDM).Reference SSCs were obtained from gravimetric analysis of 219 automatically pumped water samples.LISST additionally supplied PSD every minute. The median particle diameter, d_(50), was usually 15μm and increased occasionally to 100μm. The turbidimeter and the ADM underestimated the SSC when the transported particles were coarser than usual. Such temporary biases resulted from the poor correlation between d_(50) and SSC at this study site. The SSCs from CFDM and LISST were not or less biased by PSD variations. Mainly due to angular and flaky particle shapes, SSC from LISST needed a correction by 79% on average. With the usually prevailing silt particles, an optical path length of 5 mm and no dilution, the SSC measurement range of LISST was limited to about 1.5 g/l. The CFDM allowed measuring higher SSC than the other investigated instruments(e.g. up to 13.5 g/l). With a periodic offset correction, its relative SSC measurement uncertainty was 20% for SSC≥ 1.5 g/I. To reliably measure a wide range of SSC with temporarily variable PSD, a combination of instruments is recommended: e.g. a standard LISST, a CFDM,and an automatic water sampler for gravimetric reference measurements.  相似文献   

Multi scenario seismic hazard assessment for Egypt     

Shaimaa Ismail Mostafa  Abd el-aziz Khairy Abd el-aal  Mohamed Ahmed El-Eraki 《Journal of Seismology》2018,22(3):669-696

Egypt is located in the northeastern corner of Africa within a sensitive seismotectonic location. Earthquakes are concentrated along the active tectonic boundaries of African, Eurasian, and Arabian plates. The study area is characterized by northward increasing sediment thickness leading to more damage to structures in the north due to multiple reflections of seismic waves. Unfortunately, man-made constructions in Egypt were not designed to resist earthquake ground motions. So, it is important to evaluate the seismic hazard to reduce social and economic losses and preserve lives. The probabilistic seismic hazard assessment is used to evaluate the hazard using alternative seismotectonic models within a logic tree framework. Alternate seismotectonic models, magnitude-frequency relations, and various indigenous attenuation relationships were amended within a logic tree formulation to compute and develop the regional exposure on a set of hazard maps. Hazard contour maps are constructed for peak ground acceleration as well as 0.1-, 0.2-, 0.5-, 1-, and 2-s spectral periods for 100 and 475 years return periods for ground motion on rock. The results illustrate that Egypt is characterized by very low to high seismic activity grading from the west to the eastern part of the country. The uniform hazard spectra are estimated at some important cities distributed allover Egypt. The deaggregation of seismic hazard is estimated at some cities to identify the scenario events that contribute to a selected seismic hazard level. The results of this study can be used in seismic microzonation, risk mitigation, and earthquake engineering purposes.  相似文献   

Observed failure modes of unreinforced masonry buildings during the 2015 Hindu Kush earthquake     

Ismail  Najif  Khattak  Nouman 《地震工程与工程振动(英文版)》2019,18(2):301-314

On 26 th October 2015, an Mw 7.5 earthquake struck northern Pakistan, with its epicenter located 45 km southwest of Jarm in the Hindu Kush region of Afghanistan. The earthquake resulted from reverse faulting at a depth of 210 km, resulting in 280 fatalities and substantial damage to some 109,123 buildings. Regional seismicity, characteristics of recorded strong motions, damage statistics, and building performance observations are presented. Earthquake damage was mostly constrained to seismic-deficient unreinforced masonry(URM) buildings. Typical failure modes included toppled minarets, partial or complete out of plane collapse of URM walls, diagonal shear cracking in piers, flexural cracking in spandrels, corner damage, pounding damage, and damage due to ground settlement. The majority of human loss resulted due to failure of URM walls and subsequent roof collapse. URM buildings located in rural hilly areas closer to the epicenter suffered more intense and frequent damage than urban URM buildings located farther away in larger cities.  相似文献   

Comparing the passive sampler and biomonitoring of organic pollutants in water: A laboratory study     

Nahla S. El-Shenawy  Richard Greenwood  Ismail M. Abdel-Nabi  Zohour I. Nabil 《Ocean Science Journal》2009,44(2):69-77

Passive sampling could provide the solution to problems associated with costly and time consuming sampling programmes and biomonitoring. Mussels (Mytilus edulis) and Chemcatcher passive sampler were simultaneously analyzed for sequestered pesticides and polychlorinated biphenyls (PCBs) by gas chromatography with mass spectrometry (GC/MSD). The Chemcatcher passive sampler based on a solid phase extraction disc with two types of diffusion-limiting membranes (polyethelene and polysulphone), were also compared. Diuron, atrazine, irgarol and lindane were accumulated in the polysulphone passive sampler in greater concentration than in the mussels or in the other passive samplers with polyethelene limiting-membrane. Mussels can accumulate in their tissue high concentration of non polar compounds such as PCB 52, dieldren and PCB 153; more than the passive sampler with polysulphone membrane. The device with polyethelene limiting membrane has high affinity capacity to concentrate high amount of phenenthrene, dieldrin, PCB 153 and PCB 52, so it acts as a sampler for non-polar compounds. The highest uptake rate of hydrophobic compounds by Chemcatcher was observed for analytes with log octanol-water partition coefficient (K_OW) between 4.5 and 7.5. Laboratory-based studies using passive samplers to assess the potential for bioaccumulation could provide robust and reliable information at relatively low cost compared to biomonitoring data. Laboratory data obtained using passive samplers could be related to accumulation under field conditions where field assessments are required.  相似文献   

A conceptual and analytical framework for understanding the spatial effects on political actions in a new world order     

Mohamed Ismail Siddiqi 《GeoJournal》1995,37(1):161-169

All creations, except mankind, on this Universe are well organized under a natural universal system. They struggle for their survival within the territorial limits of their making. They do not have special barriers between, particularly similar to International Boundaries of Mankind. They even move from one physical region to another if the basic requirements, necessary for their survival are exhausted. Mankind is recognized as supreme to all creations, but diversity of their character, behavior, suspicious, and indifferent political ideology with uncomfortable mask on faces, have created an ending growth of conflicts through passion and reason within and outside the limits of their access, and set a criterion of moving power, to control the other limits on this universe.The basic object of writing this paper is to construct a framework or show a path leading to its construction for uniting mankind on one political platform, free from the influence of power and pressure. Keeping in mind the teaching of religious doctrine and their concept of world orders and the philosophical approaches, particularly the recent political writing of Kant towards inidvidual rights and freedom under the controlling factors of reason and passion, a framework for the new world order is possible to establish, leading to the final goal of creating a global system.  相似文献