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161.
The determination of the geometry of a vertical structure is one of the most important problems in the conventional stacking process used as an imaging process. The horizontal layers in depths of the earth are easily displayed in the seismic time section, but the dipping and folded layers are not correctly displayed in the reflection data. The present study addresses the same problem for the data collected from a profile of a steep marine valley and that of an offshore extension of the Ganos fault at the westernmost part of the Tekirdağ basin, Marmara Sea, NW Turkey. In the previous studies, the fault was interpreted as a low-angle reverse fault juxtaposing between the Plio-Quaternary and the Miocene strata in the time migration section. However, the results of the extensive analyses in this study show that the close position of a newly interpreted Miocene anticline to the synformal structure of the sea bottom makes the data ambiguous, whereas the subvertical fault and the other events coming away from the fault plane causes complexity. To eliminate misinterpretation due to ambiguity and complexity as in the previous analysis, the data are reinterpreted by pre-stack Kirchhoff depth migration in addition to the conventional stacking process. The new interpretation is checked through the synthetics data created from the model having appropriate parameters of the data used. The results have shown the existence of an anticline that is cored by the Miocene strata and overlain by the Plio-Quaternary strata 200 m below the sea bottom. The Ganos fault is imaged as disturbing all the layers down the way and as having a listric geometry and steeper dip angle (75° N) at shallow depths but decreasing downward. This study examples the importance of considering the problems of the complex geometry and choosing appropriate imaging technique for analyzing seismic reflection data collected over an area with known vertical fault and related tectonic complexity. 相似文献
162.
Oya Algan M. Namk Yaln Mehmet
zdoan sak Ylmaz Erol Sar Elmas Krc-Elmas Demet Ongan
zlem Bulkan-Yeiladal Yücel Ylmaz smail Karamut 《Quaternary Research》2009,72(3):457-461
The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour at İstanbul contains the records of sea level, environmental changes and the cultural history of the region. The cobbles at the base of the sequence include archaeological remnants of Neolithic culture that settled in the area between 8.4 and 7.3 14C ka BP, and are located at 6 m below the present sea level. The sediments representing a coastal environment indicate that the area was used as a harbour from AD 4th to at least the 11th century and were filled by the sediments derived from Lykos Stream after 11th century. 相似文献
163.
164.
Mehmet Ali Hindistan Abdullah Erhan Tercan Bahtiyar Ünver 《International Journal of Coal Geology》2010,81(3):139-150
The coal quality is an important aspect of coal mine planning. This paper presents a case study in which an underground coal mine is faced with severe penalty cost because it does not consider in situ coal quality control at all. To help short term planning of the coal production the mean calorific values of the blocks inside the production panels are estimated by kriging. The estimated calorific values are compared with those obtained from actual production. The ratio of the calorific values of actual production to estimated values is found to be 0.73 in average due to adverse effect of dilution on the quality of run-of-mine coal. This study reveals the importance of geostatistical block modelling in short term mine planning. 相似文献
165.
The effect of reservoir length on seismic performance of gravity dams to near- and far-fault ground motions 总被引:1,自引:1,他引:0
In this article, the effect of reservoir length on seismic performance of gravity dams to near- and far-fault ground motions
is investigated. For this purpose, four finite element models of dam–reservoir–foundation interaction system are prepared
by using the Lagrangian approach. In these models, the reservoir length varies from H to 4H (H: the height of dam). The Folsom gravity dam is selected as a numerical application. Two different ground motion records of
1989 Loma Prieta earthquake are used in the analyses. One of ground motions is recorded in near fault; the other is recorded
in far fault. Also, the two records have the same peak ground acceleration. The study mainly consists of three parts to assess
the effects of reservoir length on the seismic performance of the concrete gravity dam. In the first part, the linear time-history
analyses of the four finite element models prepared for the Folsom gravity dam are performed. In the second part, the seismic
performance of the dam is evaluated according to demand–capacity ratio and cumulative inelastic duration. Finally, the nonlinear
time-history analyses of the finite element models of the dam are carried out by using Drucker–Prager yield criteria for dam
concrete. It is seen from the analyses results that the seismic behavior of the concrete gravity dams is considerably affected
from the length of the reservoir. The reservoir length of 3H is adequate for concrete gravity dams. The selection of ground motion is on of the important parts of seismic evaluation
of gravity dams. Also, the frequency characteristics of the ground motion having the same peak ground acceleration affect
the seismic performance of the dam. The near-fault ground motions are generally creates more stress on the dam body than far-fault
ground motions. The used performance approach provides a systematic methodology for assessment of the seismic performance
and necessity of nonlinear analyses for dam systems. 相似文献
166.
167.
The Beypazarı granitoid in central Anatolia was emplaced during the Late Cretaceous and it is partly covered with Early Miocene–Quaternary sedimentary and volcanic units. Compression and tension regimes of the Beypazarı granitoid emplacing along the Sakarya River were evaluated considering the kinematical characteristics of discontinuities on granitoids, petrographic/geochemical works, formation of geothermal spring and irregularities in topographic structure. It was determined that the Beypazarı granitoid was witnessed with NE–SW compressional stress and NW–SE extensional stress which resulted in the formation of the Kapullu normal fault with N55–72°E, 78°SE crossing the Kapullu spring site. There are also several other probable normal faults around this fault in the Sakarya River basin. The results of the geochemical studies reveal that SiO2, Na2O, Al2O3, CaO and K2O as a major oxide and As, Rb, Sr, Th and U as trace elements are decreased away from the Kapullu bath spring. On the other hand, the ratio of Fe2O3 and MgO as major oxide and Y as a trace element with the lost on ignition (LOI) are increased away from the Kapullu fault. Regard as the regional plate tectonism, there is a consistency between the direction of compression in the Beypazarı granitoid and that developed by the southwesterly movement of the Anatolian plate. 相似文献
168.
Mehmet Aktas Galip Aydin Andrea Donnellan Geoffrey Fox Robert Granat Lisa Grant Greg Lyzenga Dennis McLeod Shrideep Pallickara Jay Parker Marlon Pierce John Rundle Ahmet Sayar Terry Tullis 《Pure and Applied Geophysics》2006,163(11-12):2281-2296
We describe the goals and initial implementation of the International Solid Earth Virtual Observatory (iSERVO). This system is built using a Web Services approach to Grid computing infrastructure and is accessed via a component-based Web portal user interface. We describe our implementations of services used by this system, including Geographical Information System (GIS)-based data grid services for accessing remote data repositories and job management services for controlling multiple execution steps. iSERVO is an example of a larger trend to build globally scalable scientific computing infrastructures using the Service Oriented Architecture approach. Adoption of this approach raises a number of research challenges in millisecond-latency message systems suitable for internet-enabled scientific applications. We review our research in these areas. 相似文献
169.
In this paper, a technique is proposed in order to study triple time series. It combines the variable of interest, sulfur
dioxide (SO2) with two related meteorological variables. Hence, three variables measured at the same time points are jointly analyzed.
Instead of using classical multiple time series analysis, it is suggested to consider the measurements of the two meteorological
variables as coordinates of a two-dimensional space and the simultaneous observation of the third variable (associated SO2 concentrations) at each pair of coordinates. Subsequently, well-known optimum interpolation is used for predicting the SO2 concentrations on the basis of six meteorological variables. All the variables of the study are measured at the same times
(all days in 2000) around the city of Istanbul, Turkey. The triple diagrams, in the form of contour maps, help to answer various
questions concerning the SO2 concentration variability with respect to meteorological variables. The same diagrams also provide a basis for the prediction
of SO2 concentrations. It is shown that the relative prediction error is less than 10%, which is acceptable for the practical studies. 相似文献
170.
The purpose of this study is to investigate the quality and usage possibility of groundwater in the Çavuşçayı basin and suggest the best water structure for the groundwater use. Results from hydrochemical analyses reveal that groundwater is mostly affected by salty (Na+–Cl−) waters of the Incik Formation and brackish (Ca2+, Mg2+–SO
4
2−
) waters of the Bayındır Formation. The Alibaba saltpan discharged (2 l/s) from the Incik Formation is used for salt production. In the basin, salinity risk increases with depth and along the groundwater flow direction. Therefore, shallow water and trenches opened in the alluvium aquifer at the east of the basin were determined to yield suitable water with no Na+ and Cl− contamination. Following the heavy rainy period, waters of less salinity and conductivity are possibly used for agriculture. 相似文献