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我国地震科技进步的回顾与展望（一） 总被引：9，自引：2，他引：9
本文对近半个世纪以来我国地震科技发展所经历的艰辛历程和所取得的长足进步作了简要回顾。阐明了如下3点：（1）全社会对减轻地震灾害及减轻地震对社会经济生活影响的强烈要求是推动我国地震科技发展的强劲动力；（2）为人民生命财产安全、经济可持续发展和社会稳定提供更好的保障是推动我国地震科技发展的根本目的；（3）坚持地震监测等技术系统建设与地震科学研究的辩证统一，并处理好任务性、科学性、可行性之间的关系是推动我国地震科技进步性质遵循的重要原则。地震预报预防工作所取得的某些成功和所遭受的许多挫折不断加深了人们对地震的发生条件和孕育发生过程复杂性的认识，促进了地震监测等技术系统的改造与现代化建设和地震科学研究的深入。尤其是20世纪最后5年，地震监测等技术系统的改造和现代化建设使地震预报预防研究与实践的技术支撑得到较明显的改善，既突出重点，又广泛探索的地震科学研究，使人们对我国大陆地震的发生条件和孕育发生过程，以及震害特征与机理研究等取得一些新的重要认识。所取得的长足进步不仅使防震减灾工作实效得以明显提高，而且为加速新世纪，首先是“十五”期间我国地震科技的进步进一步奠定了基础。在回顾历史的基础上，阐明了当前和今后一段时期我国地震科技发展的总体要求和应重点加强的10个方面的工作，即地震观测台网的数字化改造与建设；地震前兆观测台网的改造与建设；强地震动观测台网的建设；地震实验室的建设；地震信息和应急指挥与紧急救援技术系统的建设；地震短临预报的研究；地震中长期预报的研究；地震动衰减和震害机理与震害控制的研究；城市地震活动断层探测与震害预测的研究；地震科学和地球科学有关领域的基础研究。期望通过这些努力使我国地震科技全面达到国际先进水平，地震预报预防的理论、技术、方法显著改进，防震减灾工作实效显著提高。 相似文献
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Gill M. Martin 《Surveys in Geophysics》2014,35(3):553-575
Despite their obvious environmental, societal and economic importance, our understanding of the causes and magnitude of the variations in the global water cycle is still unsatisfactory. Uncertainties in hydrological predictions from the current generation of models pose a serious challenge to the reliability of forecasts and projections across time and space scales. This paper provides an overview of the current issues and challenges in modelling various aspects of the Earth’s hydrological cycle. These include: the global water budget and water conservation, the role of model resolution and parametrisation of precipitation-generating processes on the representation of the global and regional hydrological cycle, representation of clouds and microphysical processes, rainfall variability, the influence of land–atmosphere coupling on rainfall patterns and their variability, monsoon processes and teleconnections, and ocean and cryosphere modelling. We conclude that continued collaborative activity in the areas of model development across timescales, process studies and climate change studies will provide better understanding of how and why the hydrological cycle may change, and better estimation of uncertainty in model projections of changes in the global water cycle. 相似文献
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弹性孔隙介质分界面上的反透射系数特征,在岩性划分、流体识别、储层边界判识等方面有重要的应用.本文研究上层为含两项不混合黏性流体孔隙介质、下层为含单项黏性流体孔隙介质分界面上的反透射理论.首先根据两种孔隙介质分界面上的能量守恒得到边界条件,再将波函数、位移、应力与应变关系代入边界条件,推导出完全连通孔隙情况下,第一类纵波入射到孔隙介质分界面上的反透射系数方程.通过建立砂岩孔隙介质模型,分别分析不同孔隙流体类型、不同含油饱和度及不同入射角情况下,各类波的反透射系数特征.研究表明,第二、三类纵波反透射系数数值比第一类纵波小多个数量级,且两者对入射角的变化不敏感,但对孔隙流体性质、含油饱和度的变化较敏感,而横波反透射系数特征恰好与此相反;第一类纵波反透射系数特征比较复杂,入射角、孔隙流体的性质及含油饱和度的变化都对其产生影响.不同孔隙流体弹性物性的差异、孔隙介质中含油饱和度的变化及不同入射角引起垂向和切向应力分量的变化都会影响各类波的反透射系数特征,分析这些特征可以为研究储层含油气性提供理论基础. 相似文献
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地下岩石由岩石骨架和孔隙流体组成,通常流体含黏性.地震波在地下介质中传播时受岩石骨架和黏性流体的影响会呈现出复杂的变化.本文将流、固体位移和应力连续作为边界条件,推导出含黏性流体孔隙介质分界面上反透射系数方程;通过建立上层为饱油、下层为饱盐水的砂岩孔隙介质模型,开展反透射系数特征研究,分别分析不同频率、不同黏滞系数条件下,含黏性流体孔隙介质分界面上反透射系数随入射角的变化.研究表明,孔隙介质分界面上和等效介质分界面上的反透射系数分别随入射角的变化趋势基本一致,说明方程推导和数值计算的正确性;快纵波反透射系数受频率、流体黏性的影响较小,而快横波反透射系数在一定入射角范围内受频率、流体黏性的影响比较大;由于黏性孔隙流体的作用,慢纵波和慢横波的反透射系数受入射角、频率及流体黏性的影响都很大. 相似文献
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湖冰光谱特征是湖冰遥感反演的物理基础,是研究湖冰光学特性和空间分布的理论依据。本文以查干湖为例,使用ASD Field Spec 4便携式地物光谱仪采集冰封期不同类型湖冰、积雪和水体光谱,利用Savitzky-Golay滤波法和包络线去除法分析白冰、灰冰、黑冰、雪冰、积雪和水体的反射光谱特征,探索气泡对湖冰反射光谱特征的影响。积雪和雪冰、白冰和灰冰、黑冰和水体的反射特征随着波长的变化特征基本一致,冰的反射率介于积雪和水体之间,其中白冰的反射率高于灰冰和黑冰,在包络线去除结果中,黑冰和水体在440 nm吸收谷处的吸收面积为5.184和10.878、吸收深度为0.052和0.106,雪、雪冰、白冰、灰冰在800和1030 nm吸收谷处的吸收面积和吸收深度的变化表现为雪<雪冰<灰冰<白冰。气泡是影响湖冰光谱特征的重要因素,气泡使白冰反射率减小和黑冰反射率增大,并且气泡使得白冰在800/1030nm和黑冰在440 nm处的吸收面积和吸收深度减小,其中气泡大小和疏密程度的不同会导致湖冰反射率的影响程度存在差异。同时,本文选取时间同步的Landsat 8 OLI遥感影像,在完成辐... 相似文献
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本文将加卸载响应比的理论和方法引入到地下水位潮汐资料计算中来,从岩石的应变与应力的非线性响应分析了井水位固体潮加卸载响应比的物理。 相似文献
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在对沂水泉成因探讨、沂水水氡正常变化特征和主要影响因素分析的基础上，结合沂水水氡变化的现场分析落实和周围采样点分析结果及构造地质和流动地磁观测结果，对山东沂水水氡自2001年3月28日以来的异常变化从形成机制上进行了分析，认为沂水水氡的下降变化与应力活动增强、构造活动加剧有关。 相似文献
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Based on the examination of the global researches on oil and gas provinces and large gas fields and the analysis of the features, attributes and distribution of large gas provinces and gas fields, this paper puts forward three indicators of determining large oil and gas provinces: spatial indicator, reservoir-forming indicator and resource indicator. It classifies the gas accumulated areas and large gas provinces in China and analyzes the controlling factors on the distribution of large gas provinces and large gas fields: the lateral distribution is mainly controlled by high-energy sedimentary facies and constructive diagenetic facies, palaeo-highs and their periclinal zones, deep faults, etc, and the vertical distribution is mainly controlled by unconformities, series of evaporates and deep low-velocity highly-conductive beds, etc. It also reveals the main geological characteristics of large gas provinces and large gas fields in China. Large gas fields in four-type basins have their own characteristics and onland large gas fields are dominantly developed in foreland basins and craton basins; there are three types of gas sources, of which, coal is the main source with high gas generating intensity and varying origins; reservoir rocks of the large gas fields (provinces) are of various types and dominated generally by low-middle permeability and porosity pore-type reservoirs; structural traps and litho-stratigraphic traps coexist in Chinese large gas fields and form dense high abundance and large-area low and middle-abundance large gas fields; most of the large gas fields have late hydrocarbon-generation peaks and reservoir formation, and experienced the process of multiple-stage charging and late finalization; large gas provinces (fields) have good sealing and preservation conditions, and evaporates seals are largely developed in large and extra-large gas fields. This paper intends to shed light on the exploration and development of large gas fields (provinces) through analyzing their geological characteristics. 相似文献
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Nearly 55% of Chinese GNP is out of and 70% of large-middle cities are located in the coastal regions, where there are vast plains and river-mouth deltas, covering 14% of the total land area and 40% of the nation抯 population. Since the 1980s, the coastal… 相似文献
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为了给银川市海宝塔的修缮保护工作提供参考依据,对其动力特性及结构损伤状况开展测试和数值模拟分析。首先对海宝塔的材料强度进行测试和计算,得出塔砌体的抗压强度及弹性模量;然后对该塔进行环境激励作用下的振动响应测试,得到塔东西和南北方向的1阶频率;最后建立数值模型并分析其模态与抗震性能,得到海宝塔的动力特性与地震作用下塔体各层的层间位移角,并基于砖石古塔破坏状态位移准则以及损伤指标开展损伤分析。结果表明：海宝塔东西方向和南北方向的1阶频率较为接近,但不同楼层的振动频谱曲线差异较大,尤其是峰值点数量;楼层越高,最大位移和层间位移角越大,受损也越严重;结构总体刚度退化较为严重,存在较大安全隐患,需进一步开展深入分析并采取保护措施。 相似文献
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Flooding is one of the most costly natural disasters and thus mapping, modeling and forecasting flood events at various temporal and spatial scales is important for any flood risk mitigation plan, disaster relief services and the global (re-)insurance markets. Both computer models and observations (ground-based, airborne and Earth-orbiting) of flood processes and variables are of great value but the amount and quality of information available varies greatly with location, spatial scales and time. It is very well known that remote sensing of flooding, especially in the microwave region of the electromagnetic spectrum, can complement ground-based observations and be integrated with flood models to augment the amount of information available to end-users, decision-makers and scientists. This paper aims to provide a concise review of both the science and applications of microwave remote sensing of flood inundation, focusing mainly on synthetic aperture radar (SAR), in a variety of natural and man-made environments. Strengths and limitations are discussed and the paper will conclude with a brief account on perspectives and emerging technologies. 相似文献
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Thierry Calmus Carlos Pallares Ren�� C. Maury Alfredo Aguill��n-Robles Herv�� Bellon Mathieu Benoit Fran?ois Michaud 《Pure and Applied Geophysics》2011,168(8-9):1303-1330
The study of the geochemical compositions and K-Ar or Ar-Ar ages of ca. 350 Neogene and Quaternary lavas from Baja California, the Gulf of California and Sonora allows us to discuss the nature of their mantle or crustal sources, the conditions of their melting and the tectonic regime prevailing during their genesis and emplacement. Nine petrographic/geochemical groups are distinguished: ??regular?? calc-alkaline lavas; adakites; magnesian andesites and related basalts and basaltic andesites; niobium-enriched basalts; alkali basalts and trachybasalts; oceanic (MORB-type) basalts; tholeiitic/transitional basalts and basaltic andesites; peralkaline rhyolites (comendites); and icelandites. We show that the spatial and temporal distribution of these lava types provides constraints on their sources and the geodynamic setting controlling their partial melting. Three successive stages are distinguished. Between 23 and 13 Ma, calc-alkaline lavas linked to the subduction of the Pacific-Farallon plate formed the Comondú and central coast of the Sonora volcanic arc. In the extensional domain of western Sonora, lithospheric mantle-derived tholeiitic to transitional basalts and basaltic andesites were emplaced within the southern extension of the Basin and Range province. The end of the Farallon subduction was marked by the emplacement of much more complex Middle to Late Miocene volcanic associations, between 13 and 7 Ma. Calc-alkaline activity became sporadic and was replaced by unusual post-subduction magma types including adakites, niobium-enriched basalts, magnesian andesites, comendites and icelandites. The spatial and temporal distribution of these lavas is consistent with the development of a slab tear, evolving into a 200-km-wide slab window sub-parallel to the trench, and extending from the Pacific coast of Baja California to coastal Sonora. Tholeiitic, transitional and alkali basalts of subslab origin ascended through this window, and adakites derived from the partial melting of its upper lip, relatively close to the trench. Calc-alkaline lavas, magnesian andesites and niobium-enriched basalts formed from hydrous melting of the supraslab mantle triggered by the uprise of hot Pacific asthenosphere through the window. During the Plio-Quaternary, the ??no-slab?? regime following the sinking of the old part of the Farallon plate within the deep mantle allowed the emplacement of alkali and tholeiitic/transitional basalts of deep asthenospheric origin in Baja California and Sonora. The lithospheric rupture connected with the opening of the Gulf of California generated a high thermal regime associated to asthenospheric uprise and emplaced Quaternary depleted MORB-type tholeiites. This thermal regime also induced partial melting of the thinned lithospheric mantle of the Gulf area, generating calc-alkaline lavas as well as adakites derived from slivers of oceanic crust incorporated within this mantle. 相似文献
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Sean K. Carey Doerthe Tetzlaff Jan Seibert Chris Soulsby Jim Buttle Hjalmar Laudon Jeff McDonnell Kevin McGuire Daniel Caissie Jamie Shanley Mike Kennedy Kevin Devito John W. Pomeroy 《水文研究》2010,24(24):3591-3602
The higher mid‐latitudes of the Northern Hemisphere are particularly sensitive to climate change as small differences in temperature determine frozen ground status, precipitation phase, and the magnitude and timing of snow accumulation and melt. An international inter‐catchment comparison program, North‐Watch, seeks to improve our understanding of the sensitivity of northern catchments to climate change by examining their hydrological and biogeochemical responses. The catchments are located in Sweden (Krycklan), Scotland (Mharcaidh, Girnock and Strontian), the United States (Sleepers River, Hubbard Brook and HJ Andrews) and Canada (Catamaran, Dorset and Wolf Creek). This briefing presents the initial stage of the North‐Watch program, which focuses on how these catchments collect, store and release water and identify ‘types’ of hydro‐climatic catchment response. At most sites, a 10‐year data of daily precipitation, discharge and temperature were compiled and evaporation and storage were calculated. Inter‐annual and seasonal patterns of hydrological processes were assessed via normalized fluxes and standard flow metrics. At the annual‐scale, relations between temperature, precipitation and discharge were compared, highlighting the role of seasonality, wetness and snow/frozen ground. The seasonal pattern and synchronicity of fluxes at the monthly scale provided insight into system memory and the role of storage. We identified types of catchments that rapidly translate precipitation into runoff and others that more readily store water for delayed release. Synchronicity and variance of rainfall–runoff patterns were characterized by the coefficient of variation (cv) of monthly fluxes and correlation coefficients. Principal component analysis (PCA) revealed clustering among like catchments in terms of functioning, largely controlled by two components that (i) reflect temperature and precipitation gradients and the correlation of monthly precipitation and discharge and (ii) the seasonality of precipitation and storage. By advancing the ecological concepts of resistance and resilience for catchment functioning, results provided a conceptual framework for understanding susceptibility to hydrological change across northern catchments. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Present changes in the regime and structure of mouths of rivers, which empty into the Caspian Sea, are discussed. The similarities and differences of these processes at the mouths of different rivers of the Caspian Region were revealed. Assessment was made of the impact of changes in river water runoff and sediment load and in the Caspian Sea level as well as the nearshore zone relief and local hydraulic engineering activities on the processes under study. Anomalous features of the processes occurring at the mouths of the Volga and Terek rivers were revealed and explained. Hydrological and morphological processes typical of the present mouths of the rivers of Ural, Sulak, and Kura were revealed; these processes could be accepted as universal and possible analogs in assessing the expected changes at the mouths of other rivers in Russia and the world in the XXI century. 相似文献