Lithologic and structural analysis of a part of western Turkey by using Landsat Tm data

Online access for this thesis was created in part with support from the Institute of Museum and Library Services (IMLS) administered by the Nevada State Library, Archives and Public Records through the Library Services and Technology Act (LSTA). To obtain a high quality image or document please contact the DeLaMare Library at https://unr.libanswers.com/ or call: 775-784-6945.The lithology and structure of the Korucu-Dugla area in western Turkey have been studied using Landsat TM data. Image processing techniques were used to discriminate the lithologies and structure as well as associated areas of hydrothermal alteration. A lineament map and rose diagram were prepared using high-pass Laplacian filters

Slip distribution and stress changes associated with the 1999 November 12, Duzce (Turkey) earthquake (M (w)=7.1)

The 1999 November 12 Duzce earthquake (M (w) = 7.1) was apparently the eastward extension of the August 17, Izmit earthquake (M (w) = 7.4). The Duzce event caused heavy damage and fatalities in the cities of Duzce and Bolu. Here a finite-fault inversion method with five discrete time windows is applied to derive the co-seismic slip distribution of the Duzce earthquake. The fault plane is best modelled as a 40 x 20 km(2) plane, with a strike of 262degrees and a dip of 65degrees to the north, and that the majority of slip occurred in two distinct patches on either side of the hypocentre, implying bilateral rupture. The possible triggering of this event by the Izmit earthquake is investigated using Coulomb stress modelling of all large events since 1943 with the inclusion of secular loading. The results show that although the Duzce rupture plane was in a stress shadow prior to the Izmit earthquake, that event caused a significant Coulomb stress load, taking the Duzce fault out of the stress shadow, which probably precipitated failure. A comparison of the mapped Coulomb stress change with the inferred slip shows no correlation between the two. Finally, the stress modelling indicates that the northern branch of the North Anatolian fault zone, beneath the Sea of Marmara towards the city of Istanbul, is presently the most highly loaded segment of the North Anatolian Fault Zone

FAM20: an evolutionarily conserved family of secreted proteins expressed in hematopoietic cells

BACKGROUND: Hematopoiesis is a complex developmental process controlled by a large number of factors that regulate stem cell renewal, lineage commitment and differentiation. Secreted proteins, including the hematopoietic growth factors, play critical roles in these processes and have important biological and clinical significance. We have employed representational difference analysis to identify genes that are differentially expressed during experimentally induced myeloid differentiation in the murine EML hematopoietic stem cell line. RESULTS: One identified clone encoded a previously unidentified protein of 541 amino acids that contains an amino terminal signal sequence but no other characterized domains. This protein is a member of family of related proteins that has been named family with sequence similarity 20 (FAM20) with three members (FAM20A, FAM20B and FAM20C) in mammals. Evolutionary comparisons revealed the existence of a single FAM20 gene in the simple vertebrate Ciona intestinalis and the invertebrate worm Caenorhabditis elegans and two genes in two insect species, Drosophila melanogaster and Anopheles gambiae. Six FAM20 family members were identified in the genome of the pufferfish, Fugu rubripes and five members in the zebrafish, Danio rerio. The mouse Fam20a protein was ectopically expressed in a mammalian cell line and found to be a bona fide secreted protein and efficient secretion was dependent on the integrity of the signal sequence. Expression analysis revealed that the Fam20a gene was indeed differentially expressed during hematopoietic differentiation and that the other two family members (Fam20b and Fam20c) were also expressed during hematcpoiesis but that their mRNA levels did not vary significantly. Likewise FAM20A was expressed in more limited set of human tissues than the other two family members. CONCLUSIONS: The FAM20 family represents a new family of secreted proteins with potential functions in regulating differentiation and function of hematopoietic and other tissues. The Fam20a mRNA was only expressed during early stages of hematopoietic development and may play a role in lineage commitment or proliferation. The expansion in gene number in different species suggests that the family has evolved as a result of several gene duplication events that have occurred in both vertebrates and invertebrates

Synovial fluid features and their relations to osteoarthritis severity: new findings from sequential studies

AbstractObjective Many factors are involved in the osteoarthritic process. It is not yet known which are initiators, promoters or simply results. Thus, we have evaluated some of those potentially important factors in osteoarthritis (OA) as observed sequentially for the first time in synovial fluids.DesignSynovial fluids (SF) obtained between 1992–2002 were all routinely evaluated for gross appearance, leukocyte counts and microscopic examination of wet drop preparations. We used regular and polarized light and alizarin red s stains. We separated out all OA patients, then we looked for patients who had more than two synovial fluid analyses to get sequential information. Time between first and final aspiration ranged from 2 to 7 (3.6±1.6) years and number of analyses per patients from 3 to 6 (3.3±0.7). We related synovial fluid crystals, fibrils and white blood cell count (WBC) to age, sex, disease duration and radiographic assessment according to the Kellgren–Lawrence radiographic rating system.Results Of 4523 synovial fluid examinations, we found 855 in patients with knee OA; 330 patients with adequate clinical details for comparison were included in our study. Twenty-six patients (one woman and 25 men) had sequentially examined SF.We found that 52% of those OA patients with effusions studied had crystals identified in their synovial fluid. Twenty-one percent of all the patients had CPPD crystals, 47% had hydroxyapatite, also called basic calcium phosphate (BCP) crystals and 16% had both types of crystals. Microscopically identifiable fibrils were found in 60% of SF.In sequentially examined patients, CPPD crystals and apatite (BCP) were found in 19% and 23%, respectively, at the first aspiration and, in 34% and 58% at the final aspiration. Fibrils were seen in 54% at first examination and 85% later. Apatite and fibrils showed more significant correlation with time (r=0.51,r =0.92) than did CPPD (r=0.32). SF WBC correlated only with CPPD crystals and did not increase with OA duration or severity. CPPD, apatite and fibrils all correlated with higher radiographic grades of OA.Conclusions As noted before CPPD and apatite crystals were more common in patients with more severe OA. New findings are that our sequential cases showed that there were some patients with no crystals at onset but that crystals appeared with progression of the disease. Fibril presence in SF also correlated with progression of the disease.Copyright 2003 OsteoArthritis Research Society International. Published by Elsevier Science Ltd. All rights reserved

Onto what planes should Coulomb stress perturbations be resolved?

[1] Coulomb stress maps are produced by computing the tensorial stress perturbation due to an earthquake rupture and resolving this tensor onto planes of a particular orientation. It is often assumed that aftershock fault planes are ‘‘optimally oriented’’; in other words, the regional stress and coseismic stress change are used to compute the orientation of planes most likely to fail and the coseismic stress is resolved onto these orientations. This practice assumes that faults capable of sustaining aftershocks exist at all orientations, an assumption contradicted by the observation that aftershock focal mechanisms have strong preferred orientations consistent with mapped structural trends. Here we systematically investigate the best planes onto which stress should be resolved for the Landers, Hector Mine, Loma Prieta, and Northridge earthquakes by quantitatively comparing observed aftershock distributions with stress maps based on optimally oriented planes (two- and three-dimensional), main shock orientation, and regional structural trend. We find that the best model differs between different tectonic regions but that in all cases, models that incorporate the regional stress field tend to produce stress maps that best fit the observed aftershock distributions, although not all such models do so equally well. Our results suggest that when the regional stress field is poorly defined, or in structurally complex areas, the best model may be to fix the strike of the planes upon which the stress is to be resolved to that of the main shock but allow the dip and rake to vary

Near-field propagation of tsunamis from megathrust earthquakes

We investigate controls on tsunami generation and propagation in the near-field of great megathrust earthquakes using a series of numerical simulations of subduction and tsunamigenesis on the Sumatran forearc. The Sunda megathrust here is advanced in its seismic cycle and may be ready for another great earthquake. We calculate the seafloor displacements and tsunami wave heights for about 100 complex earthquake ruptures whose synthesis was informed by reference to geodetic and stress accumulation studies. Remarkably, results show that, for any near-field location: (1) the timing of tsunami inundation is independent of slip-distribution on the earthquake or even of its magnitude, and (2) the maximum wave height is directly proportional to the vertical coseismic displacement experienced at that location. Both observations are explained by the dominance of long wavelength crustal flexure in near-field tsunamigenesis. The results show, for the first time, that a single estimate of vertical coseismic displacement might provide a reliable short-term forecast of the maximum height of tsunami waves

Indonesian earthquake: Earthquake risk from co-seismic stress.

Following the massive loss of life caused by the Sumatra-Andaman earthquake in Indonesia and its tsunami, the possibility of a triggered earthquake on the contiguous Sunda trench subduction zone is a real concern. We have calculated the distributions of co-seismic stress on this zone, as well as on the neighbouring, vertical strike-slip Sumatra fault, and find an increase in stress on both structures that significantly boosts the already considerable earthquake hazard posed by them. In particular, the increased potential for a large subduction-zone event in this region, with the concomitant risk of another tsunami, makes the need for a tsunami warning system in the Indian Ocean all the more urgent.John McCloskey, Suleyman S.Nalbant, Sandy Steac

Near-field propagation of tsunamis from megathrust earthquakes

We investigate controls on tsunami generation and propagation in the near-field of great megathrust earthquakes using a series of numerical simulations of subduction and tsunamigenesis on the Sumatran forearc. The Sunda megathrust here is advanced in its seismic cycle and may be ready for another great earthquake. We calculate the seafloor displacements and tsunami wave heights for about 100 complex earthquake ruptures whose synthesis was informed by reference to geodetic and stress accumulation studies. Remarkably, results show that, for any near-field location: (1) the timing of tsunami inundation is independent of slipdistribution on the earthquake or even of its magnitude, and (2) the maximum wave height is directly proportional to the vertical coseismic displacement experienced at that location. Both observations are explained by the dominance of long wavelength crustal flexure in near-field tsunamigenesis. The results show, for the first time, that a single estimate of vertical coseismic displacement might provide a reliable short-term forecast of the maximum height of tsunami waves