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51.
A methodology to model seismic microzonation maps is required in the hazard mitigation decision plans of the earthquake prone areas. The stage of disaster preparedness for new residential places is of great importance for detailed seismic microzonation models. The effects of local geological and geotechnical site conditions were considered in order to establish site characterization as the initial stage of the models in this study. Dynamic soil properties based on the empirical correlations between shear wave velocity (V s) and standard penetration test blow counts were taken into account in order to define representative soil profiles extending down to the engineering bedrock. One-dimensional site response analyses were performed to analyze earthquake characteristics on the ground surface. The layers for soil classification, geology, depth to groundwater level, amplification, distance to fault, slope and aspect, and liquefaction-induced ground deformation potential of the study area were prepared in seismic microzonation models. The study area, Erbaa, is placed along the seismically active North Anatolian Fault Zone. Final seismic microzonation map of the study area was evaluated applying different GIS-based Multi-Criteria Decision Analysis (MCDA) techniques. Two of the MCDA techniques, simple additive weighting and analytical hierarchical process (AHP), are considered during the evaluation step of the final seismic microzonation map. The comparison is made in order to distinguish two different maps based on these MCDA techniques. Eventually, AHP-based seismic microzonation map is more preferable for the seismic design purposes in this study. 相似文献
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53.
Oktay Erten Mehmet Siddik Kizil Erkan Topal Lachlan McAndrew 《Natural Resources Research》2013,22(3):207-227
Tropical laterite-type bauxite deposits often pose a unique challenge for resource modelling and mine planning due to the extreme lateral variability at the base of the bauxite ore unit within the regolith profile. An economically viable drilling grid is often rather sparse for traditional prediction techniques to precisely account for the lateral variability in the lower contact of a bauxite ore unit. However, ground-penetrating radar (GPR) offers an inexpensive and rapid method for delineating laterite profiles by acquiring fine-scale data from the ground. These numerous data (secondary variable) can be merged with sparsely spaced borehole data (primary variable) through various statistical and geostatistical techniques, provided that there is a linear relation between the primary and secondary variables. Four prediction techniques, including standard linear regression, simple kriging with varying local means, co-located cokriging and kriging with an external drift, were used in this study to incorporate exhaustive GPR data in predictive estimation the base of a bauxite ore unit within a lateritic bauxite deposit in Australia. Cross-validation was used to assess the performance of each technique. The most robust estimates are produced using ordinary co-located cokriging in accordance with the cross-validation analysis. Comparison of the estimates against the actual mine floor indicates that the inclusion of ancillary GPR data substantially improves the quality of the estimates representing the bauxite base surface. 相似文献
54.
Onshore and offshore seismic and geologic-morphologic evidence from the wider region of the ?anakkale Basin indicates that this area has been widely exposed to transpressional tectonism, which already commenced in the Pliocene. During this transpressional tectonism, the Gelibolu Fault and the Anafartalar Shear Zone on the Gelibolu Peninsula, as well as the Bozcaada-Biga Shear Zone on the Biga Peninsula were activated. As a consequence, the northern part of the Gelibolu Peninsula, and a broad zone between Bozcaada Island and the Karaburun Peninsula were uplifted to form the northern and southern boundaries of the ?anakkale Basin, respectively. This remained a low-elevation intermontane basin between these two highlands. The original morphology of the ?anakkale Basin may have developed as a coastal and shelf section of the large extensional Marmara Sea Basin at the end of the Late Miocene. This tectonic phase was followed in the Pliocene by the transpressional tectonism of the North Anatolian Fault Zone, which destroyed the initial morphology and formed the present V-shaped basin. The activity of the Gelibolu Fault and the Anafartalar Shear Zone along the northern boundary of the ?anakkale Basin ended in the late Pleistocene with the initiation of the northern segment of the North Anatolian Fault Zone. The tectonism along the northern boundary of the ?anakkale Basin thus shifted from a transpressional to a transtensional regime. Seismic data indicate that the Bozcaada-Biga Shear Zone continues to be active to the present day. 相似文献
55.
Geothermal exploration is typically limited to high-grade hydrothermal reservoirs that are usually found in the western United
States, yet large areas with subsurface temperatures above 150°C at economic drilling depths can be found east of the Rocky
Mountains. The object of this paper is to present new heat flow data and to evaluate the geothermal potential of Texas and
adjacent areas. The new data show that, west of the Ouachita Thrust Belt, the heat flow values are lower than east of the
fault zone. Basement heat flow values for the Palo Duro and Fort Worth Basins are below 50 mW/m2 while, in the frontal zone of the belt, they can exceed 60 mW/m2. Further east, along the Balcones fault system the heat flow is in general higher than 55 mW/m2. The eastern most heat flow sites are in Louisiana and they show very high heat flow (over 80 mW/m2), which is associated with the apparently highly radioactive basement of the Sabine uplift. The geothermal resource in this
area is large and diverse, and can be divided in high grade (temperature above 150°C) convective systems, conductive based
enhanced geothermal systems and geothermal/geopressured systems. One of the most attractive areas east of the cordillera extends
from eastern Texas across Louisiana and Arkansas to western Mississippi. Here temperatures reach exploitation range at depths
below 4 km, and tapping such a resource from shut in hydrocarbon fields is relatively easy. The initial costs of the development
can be greatly reduced if existing hydrocarbon infrastructure is used, and therefore using shut-in hydrocarbon fields for
geothermal purposes should not be neglected. 相似文献
56.
Recently acquired (2005) multi-beam bathymetric and high-resolution seismic reflection data from the E–W-oriented Gulf of Gökova off SW Anatolia were evaluated in order to assess the uneven seafloor morphology and its evolution in terms of present-day active regional tectonics. Stratigraphically, the three identified seismic units, i.e., the basement, deltaic sediments deposited during Quaternary glacial periods, and modern gulf deposits, are consistent with those observed in previous studies. Structurally, the folds and faults with strike-slip and reverse components have been regionally mapped for the first time. Of these, NE–SW-oriented left-lateral strike-slip faults with compressional components forming the so-called Gökova Fault Zone intersect and displace two WNW–ESE-oriented submarine ridges and deep submarine plains. Thus, strike-slip faults are the youngest major structures in the gulf, and control present-day active tectonism. E–W-oriented folds on the inner and outer shelf, which are generally accompanied by reverse faults, delimit the margins of these submarine ridges, and deform the young basin deposits. These features also reveal the concomitant existence of a compressional tectonic regime. The compressional structures probably represent pressure ridges along left-lateral strike-slip fault segments. However, some E–W-oriented normal faults occur on the northwestern and partly also southern shelf, and along the borders of the adjacent deep submarine plains. They are intersected and displaced by the strike-slip faults. The lower seismicity along the normal faults relative to the NE–SW-oriented strike-slip faults suggests that the former are at present inactive or at least less active. 相似文献
57.
A new natural gas pipeline with a 0.90-m diameter is under construction to provide a gas connection between Turkey and Greece
as well as to create a gas ring for southern Europe. The new pipeline route lies next to an existing small diameter gas pipeline
broken by a landslide that occurred in February 2006 near Karacabey (Bursa). Although the existing pipeline has been temporarily
repaired, either the pipeline route should be relocated or the landslide should be stabilized. The geological survey conducted
in the study area reveals that relocation is not feasible due to the existence of other landslides in close vicinity to the
site. In order to investigate the causes of the landslide and to suggest possible remedial measures, geotechnical investigations
including surface geological mapping, trial pitting, drilling with field tests, inclinometer measurements, laboratory testing,
and limit equilibrium analyses were conducted. The investigation revealed that the unconsolidated clayey soil slid on claystone
along a non-circular failure surface. Based on the gathered data, possible remedial measures including partial removal of
landslide material and construction of toe buttresses, slope flattening, lowering the pipeline, and surface drainage systems
were evaluated. These are suggested to prevent the reactivation of the landslide, and thus to establish a safe route for both
the existing and the new pipelines. 相似文献
58.
Y. Erkan 《Rock Mechanics and Rock Engineering》1971,3(2):113-120
ZusammenfassungZum Einfluß einiger Gefügeparameter auf die Würfeldruckfestigkeit der Granite Die Möglichkeit, die physikalischen Eigenschaften des Festkörpers durch einige Gefügeparameter zu erfassen, wird in der vorliegenden Arbeit erörtert.Anhand der Bestimmung der Druckfestigkeitswerte der Granitproben und der Oberflächen-und Volumendichte zwischen deren Mineralen wird gezeigt, daß die Druckfestigkeit des Gesteins mit steigender Oberflächendichte der Minerale zunimmt und daß die Volumendichte der einzelnen Minerale für die Druckfestigkeit keine Bedeutung hat.Die Ergebnisse können ferner die Bedeutung einiger metrischer und stereologischer Methoden für quantitative Erfassung von physikalischen Eigenschaften, von Gesteinsgefügen und vom modalen Mineralbestand zeigen.
Für wertvolle Anregungen, Hinweise und Korrekturen bin ich Herrn Prof. Dr. G. C. Amstutz und Herrn Dr. H. Giger sehr dankbar.
Mit 5 Abbildungen 相似文献
SummaryInfluence of Some Structural Parameters on the Compressive Strength of Granite The present paper discusses and illustrates the possibility of characterizing strength properties of rock by structural parameters.Tests including the determination of the compressive strength of granites and the surface and volume densities of their minerals indicated that the compressive strength increases with increasing surface density of the minerals, whereas no significant influence of the volume density of the individual minerals was found.
RésuméL'influence de quelques paramètres structuraux sur la résistance à la compression de granite Dans cet article l'auteur montre les relations entre les propriétés physiques des corps solides et certains paramètres de texture.Par l'étude de la resistance à la compression des granites et de la densité superficielle et volumétrique des minéraux on montre que la résistance à la compression des roches croît avec l'augmentation de la densité superficielle des minéraux, alors que la densité volumétrique des minéraux individuels, à cet égard, n'est pas significative.Par conséquent ces résultats démontrent l'importance que peuvent avoir les méthodes métriques et stéréologiques pour décrire d'une manière quantitative les propriétés physiques, les propriétés de textures et d'analyse modale des roches.
Für wertvolle Anregungen, Hinweise und Korrekturen bin ich Herrn Prof. Dr. G. C. Amstutz und Herrn Dr. H. Giger sehr dankbar.
Mit 5 Abbildungen 相似文献
59.
Cappadocian monuments that are within tuff have serious deterioration problems. Understanding the effects of lichens on the tuffs is of utmost importance. In this paper, interactions between lichen-coated surfaces of Cappadocian monuments and the rock substratum have been studied. Thin sections and freshly cut sections were investigated by light and scanning electron microscopy. The presence of clay minerals and zeolites as weathering by-products produced by alteration and hydrolysis of glass and feldspars was assessed by XRD patterns. Furthermore, some physical properties of the tuff coated by and free of lichens were measured and compared. Analysis of mineralogical data has shown that the main weathering mechanism can be identified as hydrolysis of some of the rock-forming minerals. The lichenic coat reduces the presence of water inside the rock, thus protecting the rock material from physical decay and disintegration. 相似文献
60.
Deterioration mechanisms of tuffs in Midas monument 总被引：3，自引：0，他引：3
Slightly weathered white and pink tuffs of the Midas monument have deterioration problems. In this study, depths and characteristics of the weathering zones developed within the tuffs are investigated through optical microscopy, X-ray diffractometry (XRD), chemical analyses, scanning electron microscopy (SEM) and some index parameters. Accelerated weathering tests including wetting–drying, freezing–thawing and salt crystallization are performed, and durability assessment methods are used to predict the durabilities of the tuffs. The findings are compared with field observations. By examining quantitative weathering indices and comparing them with thin section studies, it is found that thin section analyses of the crystals, LoI, and WPI are good indicators to quantify the depth of weathering for the tuffs. However, thin section studies have limited value for fine-grained tuffaceous matrix. The chemical weathering of the tuffs produces weathered zones that are 4.5-cm thick within the white tuff and 2.5-cm thick within the pink tuff. Physical weathering causes scaling of outer layers of the tuffs and fracturing of feldspars along their cleavage planes. However, variations of the index properties of the tuffs due to weathering are not so significant to quantify the weathering depths in the tuffs. Among the accelerated weathering tests, salt crystallization is found to be the most destructive environmental condition. Pigeon droppings rich in NO31− are found to be the main source of soluble salt at the Midas monument. The salt transported up by capillary rise due to surface water causes spalling of the tuffs in the capillary zone. Surface water and salt of any kind in the close vicinity of the monument should be totally eliminated for the purpose of conservation. Field observations and the durability equations reveal that the white tuff is less durable than the pink tuff. Wet-to-dry strength ratio yields a better stone durability assessment among various durability methods used in this study. 相似文献