Paper Title, Authors, Abstract (Issue 1, Volume 2, 2008)

Pages

Retrieving Slowness Distribution of a Medium between Two Boreholes from First Arrival Traveltimes
D. Ustundag

Abstract: We study a problem of reconstruction of seismic wave speed distribution from a set of measured first arrival traveltimes in presence of strong velocity contrasts, which cause the problem to be highly non-linear. In this context, we make an attempt to improve a stable iterative reconstruction algorithm by incorporating appropriate a variable regularizing parameter and also used it for a simple synthetic borehole test after writing its algorithm in a C++ code. The simulations results support the effectiveness of the method.
 

A Seismotectonic Study for the Heraklion Basin in Crete (Southern Hellenic Arc, Greece)
E. Kokinou, M. Moisidi, I. Tsanaki, E. Tsakalaki, E. Tsiskaki, A. Sarris, F. Vallianatos

Abstract: In the context of the present work the spatial distribution of the seismic activity around Crete Island in the Southern Hellenic Arc for the period 2003-2007 is studied. Especially in the period July-October 2007 about 600 events of low and moderate magnitudes have been indicated. Most of these events are located near coast and onshore of Crete. Additionally, we studied the relation of the earthquake epicenters with specific fault zones for the Heraklion basin. GIS techniques were used for mapping the distribution of earthquake epicenters on the various topographic and geological features of the area. Maps were created through interpolation algorithms. Spatial tools and statistical analysis were exploited to examine the correlation between earthquake loci and faulting orientations. The distribution of the epicenters indicates that the near coast and onshore seismicity is closely associated to the Crete tectonics. Especially for Heraklion prefecture the epicenter distribution is related to E-W, NE-SW and NW-SE striking faults.
 

    Paper Title, Authors, Abstract (Issue 2, Volume 2, 2008)

Pages

Quantitive Assessment of Soil Degradation in some Areas North Nile Delta, Egypt
Kh. M. Darwish, W. A. Abdel Kawy

Abstract: Most forms of land degradation are man-made problems, although there are some physical environmental factors involved, but mismanagement and misuse are still considered. Quantitative assessment of human induced land degradation and monitoring the changes in land qualities in Kafr EL-Sheikh Governorate during the period of 1963 to 2009 are the main objective of this study. Geometrically corrected physiographic-soil map was produced for the studied area. The comparison between the data extracted from the RISW reports, [1] and the data of this study were carried out to determine the rate of land degradation. Aerial photo-interpretation, Landsat ETM+ image, fieldwork and laboratory analysis data were used to produce the physiographic-soil map of Kafr EL-Sheikh Governorate. Land degradation rate, relative extent, degree, and severity level in the study area were assessed. The results indicate that the dominant active land degradation features are; water logging salinization, alkalinization and compaction. The main causative factors of human induced land degradation types in the studied area are over irrigation, human intervention in natural drainage, improper time use of heavy machinery and the absence of conservation measurements.
 

Late Cretaceous–Eocene Reactivations of the Hatta Shear Zone, Northern Oman Mountains
Ali M. A. Abd-Allah, Waheed A. Hashem, Osman Abdelghany

Abstract: The NW-trending Hatta Shear Zone was formed in the Late Cretaceous during the emplacement of the Tethyan rocks and oceanic crust on the eastern margin of the Arabian plate. The western end of this shear zone is draped over by the Campanian-Lower Eocene carbonate rocks. These rocks were thrusted and folded later during the Tertiary Alpine deformation event. The folds are represented by two large plunging, asymmetrical NW-oriented anticlines that are interveined with a middle box-shape syncline, in addition to, four small NE and E-W trending folds. The syncline is characterized by a 3-segmented z-shape, as separated by the two bends; one of them is occupied by NE-oriented folds while the other is occupied by E-W oriented folds. The origin of this syncline may be controlled by the displacement over NW-trending, NE-dipping en echelon thrust faults bounding it. The estimated E-W regional compressive stress that initially accompanied the Cretaceous rock emplacement was locally adopted in later stages to NE-SW orientation. This deformation took place synchronous to deposition in three stages. It is commenced during the Campanian-Late Maastrichtian and renewed in Early Paleocene and in post Early Eocene times. This NE-SW compression produced El Rawdah structures, which reflect shortening values between 14% and 29.4%. The rock mechanical properties and bed thicknesses controlled the folding mechanisms. Whereas, buckling developed open folds in the thick and relatively brittle beds of the Campanian to Maastrichtian rocks, while flexural slip folding mechanism produced tight folds in the thin and ductile beds of the Maastrichtian to Early Eocene rocks.
 

    Paper Title, Authors, Abstract (Issue 3, Volume 2, 2008)

Pages

A Novel Maximum Fuzzy Entropy Thresholding of Seismic Images
Sanjay Kumar Singh

Abstract: Image thresholding is very useful for keeping the significant part of an image and getting rid of the unimportant part or noise. This holds true under the assumption that a reasonable threshold value is chosen. The study of image thresholding techniques in earthquake engineering, remote sensing, geology and geophysics seems to be extremely important for recognition of certain patterns such as faults, folding, fracturing, thrusting, closure, salt domes, strong reflectors, seismic facies, channels, bright spots etc, and the identification of large zones of common signal texture which are not detectable so minutely by other techniques. This paper presents a novel maximum fuzzy entropy thresholding of seismic images. The concept of fuzzy probability and fuzzy partition is introduced first. Then, based on the conditional probabilities and fuzzy partition, a 2-level optimal thresholding is searched adaptively through the maximum entropy principle of the seismic images.
 

The Interaction between Water Resources and Faults: Case Study of Lar Valley in Northeast Tehran
A. Khorsandi Aghai, T. Miyata, H. Ghoreishi

Abstract: This research studies the interaction between the water resources and faults with the intention of identifying faults based on the effects of this inter-relation and their impacts on water resources. The research was conducted in the Lar valley located in the northeast of Tehran, the capital of Iran. The results indicate the influence of faults on 60% of Lar valley’s rivers as well as on the quality of Sefidab River. The location of 57.5% of the springs was also influenced by the fault’s actions and the change in the height of wellspring from 2500 to 3800 was attributed to the fault’s impact. 32.5% of the springs were of karstic, while 54% were of contact and 46% of overflow type, originating from the limestone (karstic), sandstones, siltstones, shale, tuff and volcanic rocks as well as the quaternary sedimentations. The water quality of most springs is thought to be influenced by faults. The results of this research complement the previous methods and they can be applied in addition to other procedures in similar cases to identify faults having an impact on surface or ground water resources.
 

Soil Study and Interpretation Procedures in Tourkovounia Hills of Attica, Greece
Dimitrios S. Oikonomou, Lambros Ekonomou

Abstract: This work is a soil study which its purpose is to analyze and study the physicochemical properties of soil in the region of Tourkovounia hills of Attica, based on the samples that collected. Fifteen soil samples were collected from different parts of the analyzed area and several laboratory tests were carried out on them. The purpose of this study and laboratory tests is a deeper understanding of the soil nature and formation in the region of Tourkovounia hills of Attica, as well as the possibility of exporting valuable conclusions for the whole region.
 

Digital Geologic Mapping Methods: From Field to 3D Model
M. De Donatis, S. Susini G. Delmonaco

Abstract: Classical geologic mapping is one of the main techniques used in geology where pencils, paper base map and field book are the traditional tools of field geologists. In this paper, we describe a new method of digital mapping from field work to buiding three dimensional geologic maps, including GIS maps and geologic cross-sections. The project consisted of detailed geologic mapping of the are of Craco village (Matera - Italy). The work started in the lab by implementing themes for defining a cartographic base (aerial photos, topographic and geologic maps) and for field work (developing symbols for outcrops, dip data, boundaries, faults, and landslide types). Special prompts were created ad hoc for data collection. All data were located or mapped through GPS. It was possible to easily store any types of documents (digital pictures, notes, and sketches), linked to an object or a geo-referenced point. Immediate thematic categorization of mapped objects, correct dimensions and positions allow to collect, interpret, and interpolate all data directly in the field. After field, the lab work was carried out keeping data separate from interpretation thanks to database opportunities. Finally, the geological map was interpreted in order to draw geologic sections and to build three-dimensional geologic model of the area.
 

Geological Investigation for Environmental Impact Assessment (EIA): Case Studies from Some of Mini Hydropower Projects in Sri Lanka
Nanda Wipula, Bandara Balasooriya

Abstract: The geological investigation is a very important factor for the environmental impact assessment (EIA) study for any development project. The major objectives of this geological investigation are to identify existing surface and sub-surface geological conditions of selected locations for the main structures of the project, to describe stability condition of soil overburden and the bed rock, to analyze geological hazard situation of the area and to recommend appropriate precautionary measures to mitigate anticipated environmental impacts due to unfavorable geological conditions. At present study was focused to conduct the geological investigations for some of the mini-hydropower projects in Central Highlands of Sri Lanka. The mini hydropower project mainly consists of diversion weir, fore bay tank, penstock line and a power house. The locations of the above structures have been selected after the preliminary field and literature survey. For the purpose of this geological survey, the evaluation of general aspects of in-situ ground stability of the proposed location of the weir site, fore bay tank, penstock line connecting the fore bay tank, the power house have been investigated. On an appraisal of the analysis of data collected in the field and conclusion made based on the field observations, the proposed locations to construct the mini hydropower projects where moderate level of geological hazards and landslide risk exists can be recommended for the above projects only with the applications of location specific guidelines and precautionary measures for the prevention of future geologic hazards. It is advised to adhere to some recommendations for the sound construction and operation of the proposed mini hydropower projects.
 

    Paper Title, Authors, Abstract (Issue 4, Volume 2, 2008)

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A Study on Light Expended Clay Aggregate (LECA) in a Geotechnical View and its Application on Greenhouse and Greenroof Cultivation
Siamak Boudaghpour, Shervin Hashemi

Abstract: Increasing population in the world increases the demand of housing and it causes destroying pasture lands and jungles immethodically. It also causes soil attrition in every country of the world. In this way, the demand of making flowerbeds in the inner and outer parts of the building increases. But expending method of making these flowerbeds as they need an environment to keep the plant and also not to be harmful for the plant and environment and also they are needed to be light and economical. According to our studies, LECA has some specific properties which can be apply as a suitable material. In this study, first the LECA and its suitable properties has been introduced in a geological and geotechnical view. Then the LECA application on greenhouse cultivation has been reviewed and a new method of making green roof by using LECA.
 

The New Prediction of the Minimum Miscible Pressure by Iranian Fractured Reservoirs
S. Torfi, E. Novieri

Abstract: The aim of this study is to develop a new model to predict the minimum miscibility pressure (MMP) of Iranian oil reservoirs. So far, different MMP correlations and models regarding the kind of injection gas and the mechanism of miscibility have been proposed, which are respectively based on mathematical and thermodynamic calculations. None of these correlations can be used with enough confidence and applying them for Iranian reservoirs is more or less prone to errors. In this article, compositional and empirical models introduced for predicting MMP regarding the composition of the injected gas and the condition in which miscible displacement is done have been studied. Experimental data from Iranian oil reservoir b with different injection gases carried out by slim-tube test have been used to obtain a new MMP correlation that is suitable to be applied to Iranian oil reservoir. By applying the new MMP correlation, one can determine minimum miscibility pressure of Iranian oil reservoir with more accuracy and within a shorter period of time. The predicted MMPs are compared with the experimental results reported from the above reservoirs .The sensitivity analysis is done and consequently their error percentage are determined and reported. Therefore, a suitable model with less error and more precision is introduced. It is shown that the results obtained from the new MMP model are more accurate when they are compared with other most common correlations reported in literature.
 

Study of the Causes for a Landslide Occurring on a National Road
Voicu Cristina Otilia, Mirea Monica

Abstract: In the beginning of the report, the authors present several general considerations regarding the geographic, geological and climatic placement of the area where the landslide occurred. Further on, the situation regarding stability conditions and technical state of the affected road is described. After the analysis of the geotechnical and technical-geological aspects, its causes and characteristics are established. Following these aspects, the report presents the recommended and applied consolidation solution.
 

Microstructural Characteristics of Saprolite with Different Weathering Degree
Hu Ruilin, Li Lihui, Yue Zhongqi, Wang Lichao, Fan Linfeng

Abstract: Microstructural characteristics of saprolite with different wheathering degrees is obtained based on SEM images. A new index—plagioclase solution degree is proposed to evaluate the weathering degree of saprolite. Application in three sections of Hong Kong suggests that the new index is sensitive to saprolite and that it can identify the degrees of weathering.