排序方式： 共有9条查询结果，搜索用时 15 毫秒
1
1.
Erkan Aydar Alain Gourgaud Inan Ulusoy Fabrice Digonnet Philippe Labazuy Erdal Sen Hasan Bayhan Turker Kurttas Arif Umit Tolluoglu 《Journal of Volcanology and Geothermal Research》2003,123(3-4):301-312
Mount Nemrut, an active stratovolcano in eastern Turkey, is a great danger for its vicinity. The volcano possesses a summit caldera which cuts the volcano into two stages, i.e. pre- and post-caldera. Wisps of smoke and hot springs are to be found within the caldera. Although the last recorded volcanic activity is known to have been in 1441, we consider here that the last eruption of Nemrut occurred more recently, probably just before 1597. The present active tectonic regime, historical eruptions, occurrence of mantle-derived magmatic gases and the fumarole and hot spring activities on the caldera floor make Nemrut Volcano a real danger for its vicinity. According to the volcanological past of Nemrut, the styles of expected eruptions are well-focused on two types: (1) occurrence of water within the caldera leads to phreatomagmatic (highly energetic) eruptions, subsequently followed by lava extrusions, and (2) effusions–extrusions (non-explosive or weakly energetic eruptions) on the flanks from fissures. To predict the impact area of future eruptions, a series of morphological analyses based on field observations, Digital Elevation Model and satellite images were realized. Twenty-two valleys (main transport pathways) were classified according to their importance, and the physical parameters related to the valleys were determined. The slope values in each point of the flanks and the Heim parameters H/L were calculated. In the light of morphological analysis the possible impact areas around the volcano and danger zones were proposed. The possible transport pathways of the products of expected volcanic events are unified in three main directions: Bitlis, Guroymak, Tatvan and Ahlat cities, the about 135 000 inhabitants of which could be threatened by future eruptions of this poorly known and unsurveyed volcano. 相似文献
2.
This paper presents probable effects of climate change on soil moisture availability in the Southeast Anatolia Development Project (GAP) region of Turkey. A series of hypothetical climate change scenarios and GCM-generated IPCC Business-as-Usual scenario estimates of temperature and precipitation changes were used to examine implications of climate change for seasonal changes in actual evapotranspiration, soil moisture deficit, and soil moisture surplus in 13 subregions of the GAP. Of particular importance are predicted patterns of enhancement in summer soil moisture deficit that are consistent across the region in all scenarios. Least effect of the projected warming on the soil moisture deficit enhancement is observed with the IPCC estimates. The projected temperature changes would be responsible for a great portion of the enhancement in summer deficits in the GAP region. The increase in precipitation had less effect on depletion rate of soil moisture when the temperatures increase. Particularly southern and southeastern parts of the region will suffer severe moisture shortages during summer. Winter surplus decreased in scenarios with increased temperature and decreased precipitation in most cases. Even when precipitation was not changed, total annual surplus decreased by 4 percent to 43 percent for a 2°C warming and by 8 percent to 91 percent for a 4°C warming. These hydrologic results may have significant implications for water availability in the GAP as the present project evaluations lack climate change analysis. Adaptation strategies – such as changes in crop varieties, applying more advanced dry farming methods, improved water management, developing more efficient irrigation systems, and changes in planting – will be important in limiting adverse effects and taking advantage of beneficial changes in climate. 相似文献
3.
Hamid M. K. Al-Naimiy Ala A. J. Al-Douri Abdalla A. Alnajjar Umran Inan 《Earth, Moon, and Planets》2009,104(1-4):189-193
The proposed research project is aiming for providing basic data for quantitative comparison of lightning-induced disturbances of the ionosphere and the radiation belts in the American, European and Asia sectors. Most of the current data on such phenomena has so far been obtained in the western hemisphere, and the weight of scientific information indicates that lightning-induced effects at high altitudes and in the radiation belts may dominate other processes on a global scale. The proposed research project will facilitate the establishment and conduct of Very Low Frequency observations in the United Arab Emirates as a part of the Asia sector, thus providing a basis for comparison to facilitate global extrapolations and conclusions. Under the proposed project, Stanford University partners with Sharjah University, deploying one of their Very Low Frequency receivers at Sharjah University campus. Sharjah University provides the data digitization and recording equipment to facilitate continuous acquisition of the data. All data from the proposed project will be available for analysis over the Internet, and a series of annual visits are planned to maximize interactions and information exchange between the two universities. 相似文献
4.
Deep petroleum occurrences in the Lower Kura Depression, South Caspian Basin, Azerbaijan: an organic geochemical and basin modeling study 总被引：1，自引：0，他引：1
Sedat Inan M. Namik Yalin Ibrahim S. Guliev Kerem Kuliev A. Akper Feizullayev 《Marine and Petroleum Geology》1997,14(7-8)
High sedimentation rates (as much as 2500 m/Ma) during Pliocene-Pleistocene, with a resultant undercompacted section as thick as 10,000 m, and lower than normal geothermal gradients are the main characteristics which have created all the means for generation and preservation of oil at deep layers in the Lower Kura Depression.Oils collected from eight different oil fields for analyses seem to have originated from a common source rock which probably is clastic, deposited in relatively subanoxic to suboxic transitional marine environment receiving low to moderate input of terrestrial organic matter.Oils from shallow (< 3000 m) and cold (< 70–80°C) reservoirs have been altered to various extent by bacterial activity.A computer-aided basin modeling study has been carried out to outline the spatial variation of the oil window and thus help in further identification of possible source rocks for the reservoired oil in the Lower Kura Depression. Results suggest that the potential hydrocarbon source horizons of the Miocene and Pliocene Red Bed Series of the so called Productive Succession are, even at depocenter areas, immature with respect to oil generation, and thus, are very unlikely to have been source rocks for the reservoired oils. However, the Oligocene-Lower Miocene Maykop rocks are marginally mature to mature depending on locality and the Eocene and older rocks are mature with respect to oil generation at all representative field locations. Oil generation commenced at the end of Pliocene and continues at present at depths between 6000 and 12,000 m.An unusually deep (> 10,000 m) oil window in the depocenter areas has been caused by the depressed isotherms due to extremely high sedimentation rates (up to 3000 m/Ma) for the last two million years. The main phase of oil generation is taking place at depths greater than what most of the wells in the study are have reached. 相似文献
5.
Merve Zeyrek Kadriye Ertekin Sibel Kacmaz Cemil Seyis Sedat Inan 《Geostandards and Geoanalytical Research》2010,34(1):67-77
A single-column suppressed ion chromatography technique was employed for the simultaneous determination of major and trace anions in sulfaterich groundwater samples. An analytical column, a self regenerating suppressor and sodium carbonate as the eluent were used to separate the anions. Method detection limits for the anions of interest were 10.4, 15.9, 36.8, 62, 60, 61 and 67 μg l−1 for F− , Cl− , NO2 − , Br− , NO3 − , PO4 3− and SO4 2− respectively. The precision of the method was tested at five different concentration levels for each anion reference sample to evaluate the effectiveness of the method for groundwater analysis. Recovery studies were performed between two successive months by adding reference samples to the geothermal groundwater and drinking water samples. Precision was also assessed as the relative standard deviation of both repeatability (within-day) and reproducibility (between-day and different concentrations) for groundwater samples. Standard deviation and RSD values of 220 groundwater samples acquired over 8 months were evaluated. The suppressed ion chromatography technique was found to be a suitable method for determining major anions in sulfate-rich geothermal water samples. 相似文献
6.
Calc-alkaline rocks of the Hasan Dagi volcano (Central Anatolia, Turkey) are products of arc volcanism triggered by continental
collision. Volcanic rocks of the Hasan Dagi range in composition from basalt to rhyolite but are dominated by andesite and
dacite. Considering only the mass transfer part of the process leads to an incomplete picture of magma chamber processes.
The exclusion of simultaneous calculations of heat and mass transfer between mixing magmas, however, has prevented petrologists
from gaining new insights into the magma mixing process. Thus, we report our experimental results in conjunction with modeling
with MELTS to test the ideas concerning the petrogenesis of Hasan Dagi volcanic rocks and quantitatively model the relevant
petrogenetic processes. Our results demonstrate that the chemical diversity of Hasan Dagi volcano is inconsistent with the
closed-system crystallization and differentiation. Thus, (1) our experimental modeling, (2) the agreement between the liquid
line of descent defined by the natural rock data and the MELTS calculations, and (3) the agreement between the mineralogy
of the rocks and calculated mineralogy corroborate the conclusion that the isobaric–isenthalpic magma mixing of basalt and
rhyolite is the major controlling process in the petrogenesis of the Hasan Dagi magmas. 相似文献
7.
Mustafa Ergin eref Keskin A. Umran Doan Yusuf Kaan Kad&#x;olu Zehra Karaka 《Marine Geology》2007,240(1-4):185-196
Backshore sediment samples from 22 beaches along the Antalya and Finike Gulfs have been studied for their grain size, chemical and heavy mineral composition. Data presented here suggest that well- to moderately-sorted (0.41 Φ–0.92 Φ) medium sand (1 Φ–2 Φ) represents dominant mean grain size in most beaches. In contrast, some beaches from the western part of the Gulf of Antalya (Göynük, Kemer-Kiriş and Beldibi) are composed of pebble- to boulder-size grained beaches which are located close to mouths of short and steep-gradient ephemeral rivers entering the sea from the Western Taurus Mountains. The heavy mineral assemblages are dominated by detrital opaque minerals (14–58% magnetite, chromite, and hematite), pyroxene (8–65% augite), amphibole (3–15% tremolite and actinolite), epidote (3–25%), garnet (2–9% pyrope and almandine) and micas (3–20 biotite, muscovite and chlorite). The very high concentrations of heavy minerals (up to 86% of bulk sediment) together with the significant concentrations of some elements found in beach sediments from the Gulf of Finike and western Gulf of Antalya (Fe: 18.40%; Cr: 10.00%; and Ti: 1.32%) are indicative of ultramafic origin, mainly derived from the ophiolitic rocks of the Antalya–Tekirova nappe on coastal hinterland. 相似文献
8.
Rock fall is a common natural hazard causing significant damage to infrastructure and loss of life and property. This paper describes selection of prevention method, construction processes and the results of a rockfall hazard assessment for the village of Sarica (Gürün region, Turkey) based on an engineering-geological model. The study area is located on the lower parts of an area with very steep cliffs and 40-500 slopes with fractured sedimentary and volcanic rocks. Detailed studies have been conducted in the region to prevent the risk of any rockfalls. Maps and charts are prepared including the rock blocks that are likely to fall and the related housing area under the risk. It was found that block sizes reached 3 m3. Rockfall analyses were performed along the selected profiles using the Rocfall V.5.0 software. Kinetic energy, bounce height, horizontal location of rock end-points and velocity of the rocks along each section were evaluated separately for each profile. This data was used to select design and construction of rockfall preventing system. In this study professional type rock fall barrier (catchment fence) was used. This method was chosen because it was cheaper, more practical and reliable than others. 相似文献
9.
Marek Gołkowski Marek Kubicki Morris Cohen Andrzej Kułak Umran S. Inan 《Acta Geophysica》2011,59(1):183-204
Variations in the global atmospheric electric circuit are investigated using a wide range of globally spaced instruments observing
VLF (∼10 kHz) waves, ELF (∼300 Hz) waves, Schumann resonances (4–60 Hz), and the atmospheric fair weather electric field.
For the ELF/VLF observations, propagation effects are accounted for in a novel approach using established monthly averages
of lightning location provided by the Lightning Image Sensor (LIS) and applying known frequency specific attenuation parameters
for daytime/nighttime ELF/VLF propagation. Schumann resonances are analyzed using decomposition into propagating and standing
waves in the Earth-ionosphere waveguide. Derived lightning activity is compared to existing global lightning detection networks
and fair weather field observations. The results suggest that characteristics of lightning discharges vary by region and may
have diverse effects upon the ionospheric potential. 相似文献
1