共查询到19条相似文献，搜索用时 62 毫秒
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提出利用全球应变率资料模拟全球地震活动特征的基本思想，并作了初步探索。利用GSRM的全球应变率场结果，初步设计了模拟全球地震活动时空分布特征的细胞自动机模型。该模型把地球考虑为一个自组织的整体系统，制定了细胞自动机的演化规则，获得了模拟的人工地震目录。初步的模拟结果基本反映了全球地震活动的主要分布特征，体现了全球构造活动强弱的主要格局，初步达到了利用GPS等实测资料计算的应变率作为细胞自动机网格状态及其改变量来模拟复杂的全球地震活动特征的实验目的。 相似文献
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在中国大陆活动地块假说及活动边界研究的基础上，将中国大陆按照地震活动特征进行分区. 利用大地震的震源机制资料和历史强震资料，结合小震综合节面解，研究了各地震区的应力应变状态，给出了各地震区的平均应力主轴方向和平均应变率. 应用地震应变能积累释放模型研究了各地震区的地震活动水平. 结果表明最大剪切应变率与地震活动水平存在线性关系. 将地震资料给出的中国大陆地壳应力应变场与GPS测量给出的结果进行了比较，初步说明了两种结果存在着统一性，从而显示出活动地块运动变形与强震活动的内在联系. 相似文献
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利用川滇南部GPS站点速度资料,采用Kriging插值和有限单元中形函数(拉格朗日差值函数)求导原则,计算了川滇南部主应变速率.在此基础上,引入Kostrov地震矩率计算方法,由主应变速率求得了研究区的地震矩率,进而借助于Ward地震平均复发间隔公式计算了研究区地震(MS≥6.5)平均复发间隔.计算结果表明,川滇南部不同震级档地震复发间隔空间分布总体上与区内主要活动断裂展布基本吻合;地震复发间隔低值区主要分布在地震活动水平和滑动速率较高的安宁河—则木河—小江断裂带、丽江—小金河断裂西南段、红河断裂西北段.所得的结果与利用历史地震资料获得的结果基本一致.该方法对于历史地震资料缺乏或不完整地区和活动断层定量研究程度较低的地区有着潜在的应用价值. 相似文献
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利用川滇南部GPS站点速度资料，采用Kriging插值和有限单元中形函数（拉格朗日差值函数）求导原则，计算了川滇南部主应变速率.在此基础上，引入Kostrov地震矩率计算方法，由主应变速率求得了研究区的地震矩率，进而借助于Ward地震平均复发间隔公式计算了研究区地震（MSge;6.5）平均复发间隔.计算结果表明，川滇南部不同震级档地震复发间隔空间分布总体上与区内主要活动断裂展布基本吻合；地震复发间隔低值区主要分布在地震活动水平和滑动速率较高的安宁河——则木河——小江断裂带、丽江——小金河断裂西南段、红河断裂西北段.所得的结果与利用历史地震资料获得的结果基本一致.该方法对于历史地震资料缺乏或不完整地区和活动断层定量研究程度较低的地区有着潜在的应用价值. 相似文献
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天山造山带构造环境复杂,活动断裂带和强震分布广泛,且主要分布于阿尔泰山、天山、西昆仑—帕米尔弧形构造带上,尤以天山地区最为集中.迄今为止,天山造山带地区的主要断裂带的活动特征与孕震应力场特征之间的动力学机理尚未有清晰的认识.本文以GPS等实际观测数据为约束,建立有限元数值模型,计算了研究区域地壳形变、应力/应变积累速率、弹性应变能密度以及库仑应力变化率等关键因素.模拟计算结果显示地表速度场与研究区域实际GPS观测值基本一致,且主要断裂带上弹性应变能密度分布与实际地震活动性也基本吻合,验证了数值模型和结果的可靠性.结合最新的观测和数值模拟结果分析发现,研究区的断层和地震活动性主要受控于近南北向的主压应力,与主要观测特征相一致.同时,帕米尔高原北部边界带—塔什库尔干断裂（TKF）、天山造山带南边界的东侧—迈丹断裂（MDF）、兴地断裂（XDF）库仑应力增大明显,在未来强震发生的可能性较高,应予密切关注. 相似文献
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John M. Lyman 《Surveys in Geophysics》2012,33(3-4):387-393
The relative significance of short multi-year linear trends in the global integral of 0–700?m ocean heat content anomaly (OHCA) is investigated by examining the overlapping segments of the 16-year OHCA curve from Lyman et al. (Nature 465:334–337, 2010). Segments of 4 years and less are found not to be significantly different from each other or from 0 at the 90% confidence interval. Likewise, short 5- to 7-year segments are not statistically different from each other. Ten-year and longer trends are significant and provide a useful comparison for satellite observations of the radiation imbalance at the top of the atmosphere. 相似文献
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自然灾害是一个全球性的问题,而地震也是不分国界的。因此,需要有一套统一而又各自独立的规范来计算全球地震风险。2009年3月9日,全球地震模型(Global Earthquake Model,简称GEM)公私合作项目正式启动,这拉开了GEM行动计划的帷幕。GEM计划由经济合作与发展组织(OECD)的全球科学论坛发起,旨在提供一个开源的透明标准,以便在全世界进行地震风险的计算模拟与相关信息的沟通交流。在此,我们对该计划的远景、目标战略、科学框架、参与者、计划实施、组织、资助等情况做一简要介绍。 相似文献
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Willis L. Webb 《Pure and Applied Geophysics》1971,84(1):89-108
Summary The atmospheric electrical structure of the earth is postulated to be controlled by a motivating force in the lower ionosphere which is produced by interaction between neutral atmosphere tidal circulations and the ionospheric plasma in the presence of the earth's magnetic field. Associated electric fields power the dynamo currents through the Hall effect with a resulting development of a gross electric potential distribution in the lower ionosphere. Asymmetries in these hemispheric potential distributions result in exospheric current flows in lowL-shells and larger differences in potential produced by dynamo return current flows in high magnetic latitudes result in strong currents through highL-shells between auroral zones. Vertical thunderstorm currents with their associated lightning discharges effectively connect the earth to a low potential region of the dynamo circuit and thus supply the earth with an average negative charge which motivates a leakage tropospheric electrical circuit. In addition, the dynamo currents maintain the magnetic polar regions at different potentials with a resulting electrical exchange with the solar wind through the earth's near space. These considerations indicate that observed electrical and variable magnetic phenomena near the earth are all part of a single comprehensive electrical current system.This paper was read byH. Dolezalek in an abbreviated form supplied by the author. 相似文献
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Erwin Groten 《Studia Geophysica et Geodaetica》1994,38(3):221-234
Summary Global tidal parameters are shown to have recently increased in accuracy, after more than twenty years of LLR and a decade of superconducting gravimetry, whereas the numerical values for the Earth have not changed substantially. Numerical values of Love numbers for terrestrial planets and the moon are also given for degrees higher than four as load numbers are basically linear combinations of Love numbers, at least for spherical non-rotation approximations. Numerical values for planetary moons, as far as they are known, have also been included in the paper. The static and dynamic behaviour of long-period and pole tide is discussed. Inner solid and outer fluid core effects are critically reviewed, also in view of a century of terrestrial tide observations of the classical type. The separation of long-period tides from secular effects (on a rotating Earth) such as Jn (n<5), is considered.Dedicated to the Memory of M. S. Molodensky 相似文献
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Global electromagnetic induction 总被引：1，自引：0，他引：1
R. G. Roberts 《Surveys in Geophysics》1986,8(3):339-374
Methods of analysis of long period geomagnetic variations (periods over a few hours), the available electromagnetic response function estimates, and the effect of lateral inhomogeneity within the Earth are reviewed. Recent advances in the inversion of response function data to produce conductivitydepth profiles are mentioned, and aspects of the inverse problem specific to global (spherical Earth) induction are discussed.There is a rapid rise in electrical conductivity between about 400 km and 800 km, but whether this is a gradual change or consists of one or several steps is not resolvable with the presently available data and naive inversion algorithm used here. At the greatest depths to which presently analysed variations penetrate (1000–1500 km), available data have some difficulty in resolving finer structure, but there are indications that the electrical structure of the continents becomes more laterally homogeneous as depth increases. Previously published inversions see lateral variations in electrical structure down to at least 500 km, and at shallower depths these variations are unambiguously resolved. 相似文献
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Izvestiya, Physics of the Solid Earth - Global geodynamics is determined by the thermal convection in the mantle which manifests itself on the surface by movements, relief, heat flow, and... 相似文献
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Previous studies have estimated that coastal cliffs exist on about 80% of the global shoreline, but have not been validated on a global scale. This study uses two approaches to capture information on the worldwide existence and erosion of coastal cliffs: a detailed literature survey and imagery search, and a GIS-based global mapping analysis. The literature and imagery review show coastal cliffs exist in 93% of the combined recognized independent coastal states and non-independent coastal regions worldwide (total of 213 geographic units). Additionally, cliff retreat rates have been quantified in at least one location within 33% of independent coastal states and 15% of non-independent regions. The GIS-based mapping used the near-global Shuttle Radar Topography Mission 3 arc second digital elevation model and Arctic Coastal Dynamics Database to obtain near-global backshore coastal elevations at 1 km alongshore intervals comprising about 1,340,000 locations (81% of the world vector shoreline). Backshore coastal elevations were compared with the mapped distribution of European coastal cliffs to produce a model training set, and this relationship was extended globally to map the likelihood of coastal cliff locations. About 21% of the transects (17% of the world vector shoreline) were identified as mangroves and eliminated as potential cliff locations. The results were combined with estimates of cliff percentages for Greenland and Antarctica from the literature, extending the global coverage to estimate cliff occurrence across 89% of the world vector shoreline. The results suggest coastal cliffs likely exist on about 52% of the global shoreline. © 2018 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. 相似文献