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1.
A combined hydrologic and hydraulic modeling approach for testing efficiency of structural flood control measures 总被引：3，自引：2，他引：1
The necessity of estimating the degree and spatial extent of positive impacts with regard to protecting communities and properties
through potential flood control projects can be considered one of the main reasons for performing flood modeling. This paper
presents an overall systematic approach based on the simulation of some extreme event conditions, using a hydrological model
to generate the resulting river flows and then using a hydraulic modeling exercise to decide upon floodplain evolution in
the case-study area, Bostanli river basin, which has been under the threat of flooding for many years. The potential serviceability
of the planned Bostanli Dam in the study area was examined by using the HEC-HMS and HEC-RAS modeling tools, both integrated
with GIS functions for spatial operations. The results indicate that the dam construction as planned would have a somewhat
positive impact as a potential flood control measure, since it seems to decrease the flood peaks of 68.9 and 158.7 m3/s (that would potentially be generated by 100- and 500-year storm events under current conditions) to 65.5 and 150.7 m3/s (when the dam is in operation), respectively. However, this seems to contribute little to the overall flood mitigation
performance in the basin. 相似文献
2.
Nilgün Kiziloĝlu 《Astrophysics and Space Science》1992,192(1):83-89
The evolutionary behaviour of rotating solar models with different initial angular-momentum distributions has been investigated through the pre-Main-Sequence and Main-Sequence phases. The angular momentum was removed from the convective evelope of the solar models according to the Kawaler's model of magnetic stellar wind (Kawaler, 1988). The models show that (i) the surface rotational velocities of the solar mass stars are independent of initial angular momentum for ages greater than 108 years and (ii) it is not possible to explain the neutrino problem and the sufficient depletion of lithium in the Sun. 相似文献
3.
Nilgün Sayil 《Acta Geophysica》2013,61(2):338-356
In order to estimate the recurrence intervals for large earthquakes that occurred in the Marmara region, this region, limited with the coordinates of 39°–42°N, 25°–32°E, has been separated into seven seismogenic sources on the basis of certain seismological criteria, and regional time- and magnitude-predictable model has been applied for these sources. Considering the interevent time between successive mainshocks, the following two predictive relations were computed: log T t = 0.26 M min + 0.06 M p –0.56 log M 0 + 13.79 and M f = 0.63 M min ? 0.07 M p + 0.43 log M 0 ? 7.56. Multiple correlation coefficient and standard deviation have been computed as 0.53 and 0.35 for the first relation and 0.66 and 0.39 for the second relation, respectively. On the basis of these relations and using the occurrence time and magnitude of the last mainshocks in each seismogenic source, the probabilities of occurrence P(Δt) of the next mainshocks during the next five decades and the magnitude of the expected mainshocks were determined. 相似文献
4.
Nilgün Sayıl 《Natural Hazards》2013,66(2):809-834
Instrumental and historical data on mainshocks for 13 seismogenic sources in western Anatolia have been used to apply a regional time- and magnitude-predictable model. Considering the interevent time between successive mainshocks, the following two predictive relations were computed: log T t = 0.13 M min + 0.21 M p ? 0.15 log M 0 + 2.93 and M f = 0.87 M min ? 0.06 M p + 0.33 log M 0 ? 6.54. Multiple correlation coefficient and standard deviation have been computed as 0.50 and 0.29, respectively, for the first relation, and 0.65 and 0.47, respectively, for the second relation. The positive dependence of T t on M p and the negative dependence of M f on M p indicate the validity of time- and magnitude-predictable model on the area considered in this study. On the basis of these relations and using the occurrence time and magnitude of the last main shocks in each seismogenic source, the probabilities of occurrence P(Δt) of the next main shocks during the next 50 years with decade interval as well as the magnitude of the expected main shocks were determined. The highest probabilities P 10 = 80 % (M f = 6.8 and T t = 13 years) and P 10 = 32 % (M f = 7.6 and T t = 29 years) were estimated for the seismogenic source 11 (Golhisar-Dalaman-Rhodes) for the occurrence of a strong and a large earthquake during the future decade, respectively. 相似文献
5.
We investigate the helium, carbon and oxygen–hydrogen isotopic systematics and CO2/3He ratios of 8 water and 6 gas samples collected from 12 geothermal fields in western Anatolia (Turkey). 3He/4He ratios of the samples (R) normalized to the atmospheric 3He/4He ratio (RA = 1.39 × 10? 6) range from 0.27 to 1.67 and are significantly higher than the crustal production value of 0.05. Fluids with relatively high R / RA values are generally found in areas of significant heat potential (K?z?ldere and Tuzla fields). CO2/3He ratios of the samples, ranging from 1.6 × 109 to 2.3 × 1014, display significant variation and are mostly higher than values typical of an upper mantle source (2 × 109). The δ13C (CO2) and δ13C (CH4) values of all fluids vary from ? 8.04 to + 0.35‰ and ? 25.80 to ? 23.92‰ (vs. PDB), respectively. Stable isotope values (δ18O–δD) of the geothermal waters are conformable with the Mediterranean Meteoric Water Line and indicate a meteoric origin. The temperatures calculated by gas geothermometry are significantly higher than estimates from chemical geothermometers, implying that either equilibrium has not been attained for the isotope exchange reaction or that isotopic equilibration was disturbed due to gas additions en route to the surface.Evaluation of He–CO2 abundances indicates that hydrothermal degassing and calcite precipitation (controlled probably by adiabatic cooling due to degassing) significantly fractionate the elemental ratio (CO2/3He) in geothermal waters. Such processes do not affect gas phase samples to anywhere near the same extent. For the gas samples, mixing between mantle and various crustal sources appears to be the main control on the observed He–C systematics: however, crustal inputs dominate the CO2 inventory. Considering that limestone is the main source of carbon (～ 70 to 97% of the total carbon inventory), the carbon flux from the crust is found to be at least 20 times that from the mantle. As to the He-inventory, the mantle-derived component is found to vary up to 21% of the total He content and is probably transferred to the crust by fluids degassed from deep mantle melts generated in association with the elevated geotherm and adiabatic melting accompanying current extension. The range of 3He/enthalpy ratios (0.000032 to 0.19 × 10? 12 cm3 STP/J) of fluids in western Anatolia is consistent with the release of both helium and heat from contemporary additions of mantle-derived magmas to the crust. The deep faults appear to have facilitated the deep circulation of the fluids and the transport of mantle volatiles and heat to the surface. 相似文献
6.
In order to investigate the seismicity of western Anatolia limited with the coordinates of 36°–40° N, 26°–32° E, Gutenberg–Richter magnitude–frequency relation, seismic risk and recurrence period have been computed. The data belonging to both the historical period before 1900 (I0 ≥ 5.0 corresponding to MS ≥ 4.4) and the instrumental period until the end of 2006 (MS ≥ 4.0) has been used in the analysis. The study area has been divided into 13 sub-regions due to certain seismotectonic characteristics, plate tectonic models and geology of the region. All the computations have been performed for these sub-regions, separately. According to the results, a and b values in the computed magnitude–frequency relations are in the intervals 3.19±0.17 – 5.15±0.52 and 0.42±0.05 – 0.66±0.07, respectively. The highest b values have been determined for sub-regions 3 and 12 (Demirci-Gediz and Gökova Gulf-Mu?la-Gölhisar). The lowest b values have also been determined for sub-regions 1 and 9 (Bal?kesir and Bodrum-?stanköy). Finally, seismic risk and recurrence period computations from a and b values have shown as expected that sub-regions 1 and 9 which have the lowest b values and the highest risks and the shortest-recurrence periods. 相似文献
7.
Süer Selin Wiersberg Thomas Güleç Nilgün Erzinger Jörg Parlaktuna Mahmut 《Natural Hazards》2020,104(2):1655-1678
Natural Hazards - This study presents the results of a real-time gas monitoring experiment conducted, via the use of a quadrupole mass spectrometer, in a mofette field within the Tekke Hamam... 相似文献
8.
Yavuz Özdemir Jon Blundy Nilgün Güleç 《Contributions to Mineralogy and Petrology》2011,162(3):573-597
Süphan is a 4,050 m high Pleistocene-age stratovolcano in eastern Anatolia, Turkey, with eruptive products consisting of transitional
calc-alkaline to mildly alkaline basalts through trachyandesites and trachytes to rhyolites. We investigate the relative contributions
of fractional crystallization and magma mixing to compositional diversity at Süphan using a combination of petrology, geothermometry,
and melt inclusion analysis. Although major element chemistry shows near-continuous variation from basalt to rhyolite, mineral
chemistry and textures indicate that magma mixing played an important role. Intermediate magmas show a wide range of pyroxene,
olivine, and plagioclase compositions that are intermediate between those of basalts and rhyolites. Mineral thermometry of
the same rocks yields a range of temperatures bracketed by rhyolite (~750°C) and basalt (~1,100°C). The linear chemical trends
shown for most major and trace elements are attributed to mixing processes, rather than to liquid lines of descent from a
basaltic parent. In contrast, glassy melt inclusions, hosted by a wide range of phenocryst types, display curved trends for
most major elements, suggestive of fractional crystallization. Comparison of these trends to experimental data from basalts
and trachyandesites of similar composition to those at Süphan indicates that melt inclusions approximate true liquid lines
of descent from a common hydrous parent at pressures of ~500 MPa. Thus, the erupted magmas are cogenetic, but were generated
at depths below the shallow, pre-eruptive magma storage region. We infer that chemical differentiation of a mantle-derived
basalt occurred in the mid- to lower crust beneath Süphan. A variety of more and less evolved melts with ≥55 wt% SiO2 then ascended to shallow level where they interacted. The presence of glomerocrysts in many lavas suggests that cogenetic
plutonic rocks were implicated in the interaction process. Blending of diverse, but cogenetic, minerals, and melts served
to obscure the true liquid lines of descent in bulk rocks. The fact that chemical variation in melt inclusions preserves deep-seated
chemical differentiation indicates that inclusions were trapped in phenocrysts prior to shallow-level blending. Groundmass
glasses evolved after mixing and display trends that are distinct from those of melt inclusions. 相似文献
9.
In order to estimate the recurrence intervals for large earthquakes occurring in eastern Anatolia, this region enclosed within
the coordinates of 36∘–42∘N, 35∘–45∘E has been separated into nine seismogenic sources on the basis of certain seismological and geomorphological criteria, and
a regional time- and magnitude-predictable model has been applied for these sources. This model implies that the magnitude
of the preceding main shock which is the largest earthquake during a seismic excitation in a seismogenic source governs the
time of occurrence and the magnitude of the expected main shock in this source. The data belonging to both the instrumental
period (MS≥ 5.5) until 2003 and the historical period (I0≥ 9.0 corresponding to MS≥ 7.0) before 1900 have been used in the analysis. The interevent time between successive main shocks with magnitude equal
to or larger than a certain minimum magnitude threshold were considered in each of the nine source regions within the study
area. These interevent times as well as the magnitudes of the main shocks have been used to determine the following relations:
fwawhere Tt is the interevent time measured in years, Mmin is the surface wave magnitude of the smallest main shock considered, Mp is the magnitude of the preceding main shock, Mf is magnitude of the following main shock, and M0 is the released seismic moment per year in each source. Multiple correlation coefficient and standard deviation have been
computed as 0.50 and 0.28, respectively for the first relation. The corresponding values for the second relation are 0.64
and 0.32, respectively. It was found that the magnitude of the following main shock Mf does not depend on the preceding interevent time Tt. This case is an interesting property for earthquake prediction since it provides the ability to predict the time of occurrence
of the next strong earthquake. On the other hand, a strong negative dependence of Mf on Mp was found. This result indicates that a large main shock is followed by a smaller magnitude one and vice versa. On the basis
of the first one of the relations above and taking into account the occurrence time and magnitude of the last main shock,
the probabilities of occurrence P(Δ t) of main shocks in each seismogenic source of the east Anatolia during the next 10, 20, 30, 40 and 50 years for earthquakes
with magnitudes equal 6.0 and 7.0 were determined. The second of these relations has been used to estimate the magnitude of
the expected main shock. According to the time- and magnitude-predictable model, it is expected that a strong and a large
earthquake can occur in seismogenic Source 2 (Erzincan) with the highest probabilities of P10 = 66% (Mf = 6.9 and Tt = 12 years) and P10 = 44% (Mf = 7.3 and Tt = 24 years) during the future decade, respectively. 相似文献
10.
Nilgün Kiziloğlu 《Astrophysics and Space Science》1989,154(2):255-269
The evolutionary behaviour of rotating low-mass stars in the mass range 0.2 and 0.9M
has been investigated during the pre-Main-Sequence phase. The angular momentum is conserved locally in radiative regions and totally in convective regions, according to a predetermined angular velocity distribution depending on the structure of the star. As the stars contract toward the zero-age Main Sequence, they spin up under the assumption that the angular momentum is conserved during the evolution of the stars. When the stars have differential rotations, their inner regions rotate faster than the outer regions. The effective temperatures and luminosities of rotating low-mass stars are obtained lower than those of non-rotating stars. They have lower central temperature and density values compared to those of non-rotating stars. 相似文献