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Microearthquake activity in the Dead Sea region   总被引:2,自引:0,他引:2  
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ABSTRACT

A majority of research on Spatial Multicriteria Analysis (SMCA) has been spatially implicit. Typically, SMCA uses conventional (aspatial) multicriteria methods for analysing and solving spatial problems. This paper examines emerging trends and research frontiers related to the paradigm shift from spatially implicit to spatially explicit multicriteria analysis. The emerging trend in SMCA has been spatially explicit conceptualizations of multicriteria problems focused on multicriteria analysis with geographically varying outcomes and local multicriteria analysis. The research frontiers align with conceptual and structural elements of SMCA and pertain to, among others, theoretical frameworks, problem structuring, model parameter derivation, decision problem contextualization, scale representation, treatment of uncertainties, and the very meaning of decision support. The paper also identifies research directions and challenges associated with developing spatially explicit multicriteria methods and integrating concepts and approaches from two distinct fields: GIS and multicriteria analysis.  相似文献   

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行为地理学的学科定位与前沿方向   总被引:1,自引:1,他引:1  
始自行为革命,行为地理学逐渐走向多元化的发展方向,不断扩展自身的理论框架和实践外延,反思并重新认识自身的意义,成为了人文地理学的重要组成部分。伴随着社会经济转型的深入,世界越来越向着多样化、个体性、动态化发展,人们的空间行为决策、选择的差异与个性越来越明显,空间与行为的交互越来越强,为行为地理学带来了新的发展机遇。论文通过梳理行为地理学的学科基础,提出行为地理学的学科定位与内涵外延,并指出行为地理学已经呈现出面向动态人地关系、面向个体生活质量及面向社会可持续发展3个前沿发展方向。在此基础上,论文对行为地理学面临的方法论、研究方法与跨学科的挑战进行讨论,并展望行为地理学的未来发展,以期为中国行为地理学的理论创新与实践探索提供启示。  相似文献   

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Lake Lisan, the lake that filled the Jordan graben during the Last Glacial, left behind a well developed sequence of erosional and depositional shore terraces in the south east of the current Dead Sea. These terraces record a series of stillstands that were caused by small transgressions within an overall trend of falling lake levels. The terraces were observed in places where they had not been identified previously. The morphology of the terraces was investigated in six cross-sections using differential GPS altimetry. The levels of the terraces range between − 370 and − 148 m a.s.l. The high stand of Lake Lisan at − 148 m correlates well with the high level of − 150 m reported by Bowman and Gross [Bowman, D., Gross, T., 1992. The highest stand of Lake Lisan: ~ 150 meters below MSL. Israel Journal of Earth-Science 41, 233–237.] along the western coast of Lake Lisan. The lake terraces are horizontal, elongated and tectonically undisturbed, and have a sub-horizontal foreshore (tread) with an average slope of 8.2° and steep backshore cliff (riser) with an average slope of 17.7°. The six cross-sections show a good altitudinal correlation between their terraces. Moreover, the terraces appear in undisturbed continuity on the aerial photos. These morphological characteristics demonstrate that the retreat of the lake was a result of substantial climatic changes, not of tectonic subsidence.In-situ stromatolites were found on most of the terraces, reflecting a shallow water environment and emphasizing that these terraces are recessional. Well-developed desert varnish and Tafoni observed on blocks sitting on the terrace surfaces imply a long period of exposure and a low rate of post lacustrine erosion. The formation of Lisan terraces is constrained mainly by coastal slope, water depth and underlying lithology. The morphological analysis of these terraces allows identification of two kinds of pseudo-terraces, which were formed as a result of tread or riser destruction.U/Th and OSL dating allowed the dating of three events within the lake level curve more precisely. The high level of − 148 m occurred at 30.5 ± 0.22 ka BP, consistent with the Heinrich Event 3 and Dansgaard–Oeschger stadial 5, the coldest period in the NGRIP Greenland Ice Core record. The next lower terrace at − 154 m was formed at 22.9 ka BP ± 0.29 and corresponds to the stadial 2C, the final phase of the Last High Glacial. The correlation between the Lisan high stands and climatic stadials suggests that Northern-Hemispheric cold periods led to periods with a more positive water balance in the Near East. At ~ 10 ± 0.8 ka BP Lake Lisan experienced a sharp drop to − 200 m followed by a transgression between 9.5 to 7 ka BP.  相似文献   

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郭如新 《盐湖研究》2005,13(4):61-66
对以色列和约旦死海中溴镁资源的开发综合利用进行了解述。包括死海卤水组成,资源储量,溴及其衍生物的镁化学制品生产现状。  相似文献   

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Measurements of dissolved oxygen, density and temperature were con ducted in the Dead Sea between August 1987 and December 1989. Oxygen concentrations were found to vary around an average value of 0.8 mlSTP (standard temperature and pressure) per kg. Dissolved oxygen variations were found to reflect both physical processes (a deepening of the epilimnion, a turnover etc.) and chemical processes (oxidation reduction). Transport coefficients for the oxygen exchange across the air/sea interface were found to be generally low compared to expected values based on laboratory experiments; the presence of surface films which inhibit the gas exchange rates under calm weather conditions is suspected. During stormy weather, the exchange rates were considerably higher, suggesting that the entrainment of bubbles was involved in the gas exchange process. Contribution No. 95, Department of Environmental Sciences and Energy Research. The Weizmann Institute of Science  相似文献   

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随着全球气候变化及淡水资源紧张,国际河流逐渐成为国际社会关注的热点和焦点。为探寻中国学者对国际河流问题的研究热点与前沿方向,基于CNKI数据库中1957—2019年的2391篇中文文献,运用CiteSpaceⅤ等工具进行文献分析和数据挖掘。结果表明:近60年来中国学者在国际河流领域的研究经历了探索起步、较快发展、全面增长、成熟发展四个阶段,研究规模和学术影响力呈现良好发展态势;主体研究力量集中于少数优势机构,跨地域、跨机构间的合作较少,机构间的联合攻关和合作网络有待加强;发文期刊从自然科学向综合社科领域扩散,国际河流问题研究的多学科、多维度、多视角特征日益明显;从地域范围上,中国西南、东北、西北三大地区的国际河流普遍受到关注,西南地区为持续重点关注区,西北地区关注热度明显上升。研究热点和前沿呈现“水电开发—次区域合作—气候变化与生态环境—一带一路—澜湄合作”的演进特征,最近十年研究热点为气候变化影响下的国际河流水资源和水生态及“一带一路”背景下的涉水合作问题。  相似文献   

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Since the mass development of halophilic bacteria in 1980 and the subsequent decline of the community in 1982, no new mass development of bacteria has occurred in the Dead Sea, and bacterial numbers have remained extremely low. The lake’s salinity, and more specifically the divalent cation concentration, have increased greatly during the last ten years. To quantitate the activity of the community of heterotrophic bacteria in the Dead Sea water column, rates of incorporation of amino acids, glycerol, and acetate were measured, both during the 1980–1981 bloom and in recent years. With the development of the bloom, rates of incorporation amino acids, glycerol and acetate increased. Concomitant with the decline in bacterial numbers, the incorporation rates of amino acids and acetate decreased at the end of 1980-beginning of 1981, while glycerol incorporation rates remained high for one more year. Measurements in 1989 and in 1991 showed very low but significant incorporation rates (three to four orders of magnitude lower than during the 1980–1981 bloom). By the use of specific inhibitors, it was shown that the remaining activity was due to halophilic archaeobacteria. The mechanism of the long-term survival of a small active bacterial community in the Dead Sea in the absence of primary producers and other obvious sources of organic carbon, and at divalent cation concentrations greatly exceeding those enabling growth, is still unknown.  相似文献   

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The dramatic lake level drop of the Dead Sea during the twentieth century ( 30 m) provides a field-scale experiment in transport-limited incision of gravel-bed channels in response to quasi-continuous base level fall at approximately constant rate. We apply a one-dimensional numerical incision model based on a linear diffusion equation to seven ephemeral channels draining into the Dead Sea. The model inputs include the measured twentieth century lake level curve, annual shoreline location (i.e., annual channel lengthening following the lake level drop), reconstructed longitudinal profiles of each of the channels based on mapped and surveyed terraces, and the current profiles of the active channels. The model parameters included the diffusion coefficient and the upstream-derived sediment flux. Both were first calibrated using a set of longitudinal profiles of known ages and then validated using additional sets of longitudinal profiles.The maximum at-station total incision observed at each of the studied channels was significantly less then the total lake level drop and varied in response to both drainage area and lake bathymetry. The model applied predicted degradation rates and the pattern of degradation with high accuracy. This suggests that sediment flux in the modeled channels is indeed linearly dependent on slope. Further support for this linear dependency is provided by a linear correlation between the diffusion coefficient and the mean annual rain volume over each basin (a proxy for discharge). The model presented could be a valuable tool for planning in rapid base level fall environments where incision may risk infrastructure.  相似文献   

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In this article, through the comparison of knowledge relating to historical earthquakes with the understanding of present-day earthquake mechanics and overall GPS slip rates in the eastern Mediterranean region, it has been possible to obtain an idea of how frequently large earthquakes may be expected in some parts of the region. It has also been possible to make an assessment from these early events of slip rates over a long period of time for the Gulf of Corinth in Greece, the Marmara Sea in Turkey and the Dead Sea Fault System, as well as deriving long-term magnitude–frequency relations for these same regions.
It has been demonstrated that slip rates calculated from historical data are in general comparable to those calculated from GPS measurements and field observations, while the size of historical earthquakes and their uncertainty can be quantified. This permits a more reliable estimation of the long-term hazard, the calculation of which is the concern of the engineering seismologist. It has also been shown that in most cases large earthquakes are less frequent when they are estimated from long-term data sets rather than from the instrumental period making the notion of recurrence time and of hazard assessment, questionable.
This study focuses on some of the few areas in the world for which long-term macroseism information exists and which facilitate this kind of analysis.  相似文献   

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Several waterbodies occupied the tectonic depressions along the Dead Sea transform during the NeogeneQuaternary. The earliest of these water bodies was the marine Sedom lagoon, which produced the SedomDead Sea brine. After the disconnection of the Sedom lagoon from the open sea several lakes were developed in the Dead Sea basinJordan Valley. Lake Amora (Samra) that existed from early to late Pleistocene, Lake Lisan (~ 70–15 kyr B.P.), and the Holocene Dead Sea. The lacustrine water bodies in the Dead Sea basin behave as amplifier lakes whose size and depth reflect the changing climatic conditions in the region. Lake level and limnological conditions of Lake Amora are not yet known, nevertheless, the lake probably extended over a large part of the Dead Sea basin-Jordan Valley. Lake Lisan level changed between ~ 330 and ~ 150 meters below sea level (m b.s.l.). Its maximum elevation was reached at ~ 27–23 kyr B.P. during marine isotope stage 2. Its minimum elevation was reached at ~ 47–43 kyr during marine isotope stage 3. Lake Lisan began to recede at ~ 17–15 kyr B.P. and at 12–11 kyr B.P. the postLisan water body declined to its minimum level. During most of the Holocene the lake (paleoDead Sea) stabilized at ~ 400 m b.s.l.The limnological evolution of water bodies in the Dead Sea basin reflects the climatic conditions in the region during the late Pleistocene, which fluctuated between wetter and drier periods. During Lisan time these fluctuations appear to be modulated by the cold and warm cycles, respectively in the northern Hemisphere. This relation is less obvious in the postLisan water body, where the strongest lake drop appears to occur during the Younger Dryas cold event.  相似文献   

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