共查询到19条相似文献，搜索用时 718 毫秒
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车用太 《水文地质工程地质》1987,(1)
我国是多地震的国家。本世纪以来,大约平均每三年发生两次7级以上的强震,1966—1976年间仅在大陆就发生八次强震,严重危害了人民的生命财产。面对着这样频繁的地震活动和几乎接连不断的地震灾害,党和国家十分重视地震工作。我国的地震水文地 相似文献
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福建减灾十年(1989-1999)正处在我省地震活动十分活跃的时期,共发生4.0级以上地震16次,其中有6次地震造成了地震灾害,使我省经济损失达2.6亿元,人员伤亡412人,并对当地的社会生活和经济建设产生了消极影响。文章分析了本省地震活动特点与灾害特征,分析了造成本省地震灾害的主要因素和地震灾害不十分严重的原因。 在福建减灾十年中,省地震部门坚持以预防为主,依靠科技进步,发挥政府减灾职能,走综合防震减灾道路;认真抓好观测数据高质量产出,各类信息处理与综合分析,震后快速应急三个环节;积极实施全省综合防御地震灾害体系建设,闽南地区综合防震减灾示范工程已经在全国综合防震减灾工作中起到示范作用,福建数字遥测地震台网工程成为中国大陆第一个正式投入观测的全省数字化地震台网;同时加快了法制建设步伐,坚持不懈地进行地震知识的科普宣传教育,努力提高全民防震减灾意识。这些措施对减轻福建十年地震灾害取得显著收益。 为了减轻我省下世纪地震灾害,提出几个值得重视的向题,防患于未然。全省地震前兆台网必须彻底改造,建设高灵敏度、高精度的数字化前兆台网,引入新的观测系统,以期捕捉未来中强以上地震的前兆信息;关注未来城市地震灾害向题,应该开展城市地震灾害环境调查与研究;加强管理,对地震烈度 相似文献
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江苏省一个中强地震活动地区。省城面积的２／３位于地震重点监视防御区内,近年来中强地震频繁发生,我国,我省的地震灾害情况,当前的地震形势以及减轻地震灾害的对策措施等都是社会和公众十分关心的问题,扼要介绍了这些方面的有关情况及一一些见解。 相似文献
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Magnitude scale and quantification of earthquakes 总被引：1，自引：0，他引：1
Hiroo Kanamori 《Tectonophysics》1983,93(3-4)
Despite various shortcomings, the earthquake magnitude scale is one of the most fundamental earthquake source parameters to be used for catalogs. Although use of a uniform scale is desirable, it is not always possible because of changes in instrumentation, the data reduction method and the magnitude formula, the station distribution, etc. As a result, various magnitude scales have been developed and are currently in use. Recent developments in seismometry and earthquake source theories provide more quantitative source parameters than the magnitude. In order to maintain continuity and uniformity of the data, it is important to relate these magnitude scales and the new parameters. In view of this importance, relations between different magnitude scales are examined with an emphasis on the difference in the period of the waves used for the magnitude determination. Use of several magnitude scales determined at different periods provides a convenient method for characterizing earthquakes. The moment magnitude can be used to quantify both shallow and deep earthquakes on the basis of wave energy radiated, and provides a uniform scheme. 相似文献
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地震是一种复杂的自然现象,其成因及发展的物理过程,目前尚在探索之中。地震预报在世界上还是一个尚未解决的难题。但是,地震预报并不是不可能的。地震既然是一种自然现象,必然有其特定的规律。 相似文献
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Akio Yoshida 《Tectonophysics》1987,140(2-4):131-143
Seismic activity in the region surrounding the foci is investigated for three severe earthquakes (two with a magnitude of 6.1 and one with a magnitude of 5.3) which have occurred in Japan in recent years. The most conspicuous feature commonly noticed is precursory activation of seismic belts which include the focal regions of main shocks. The repetition of the same pattern in the space-time distribution of earthquake occurrence along the seismic belt is also observed for each case. The precursory activity of seismic belts terminates in rather a short period and, after that, the area around the focus of the forthcoming large earthquake becomes quiescent, which demonstrates the appearance of the seismic gap of the second kind (Mogi, 1979). The periods of seismic quiescence for the cases investigated in this paper are longer than those which are given by the regression relationship between earthquake magnitude and precursor time proposed for example, by Sekiya (1977). However, our definition of anomalous seismic activity is clear, and it is possible to give a physical meaning to it as an increase in the local stress field in the seismic belt. We propose that a kind of coupling between intraplate tectonic blocks, analogous to interplate coupling in the subduction region, is responsible for the formation of the stress field relevant to these earthquakes. Although this is at present only one of the possible viewpoints on the formation of the focal region of large intraplate earthquakes, it may be worthwhile to study various precursory phenomena in-connection with this hypothesis. 相似文献
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闽台地球动力学及其能态结构研究 总被引：1，自引：0，他引：1
台湾地处中国大陆东南边缘是菲律宾海板块凸向亚欧大陆俯冲-碰撞异常岛弧带。福建位于台湾岛弧西侧活动地块。闽台独特的构造格架、地球动力学状态和构造应力场与地震活动之间的内在关联性,使之成为研究海陆板块俯冲-碰撞效应及其对板内地震活动影响天然地区。本文主要依据近30多年以来对福建地块的地震地质背景、地壳变形观测、构造应力场、地震活动性以及地壳-上地幔结构探测、地热场等资料,结合台湾学者详细对台湾岛弧地球动力学与强震构造等研究成果,探索海陆板块俯冲-碰撞地球动力学特征及其对板内活动地块影响,进而揭示板间-板缘-板内强震活动关联性和动力学性状的异同性。试图为本区强震预测和防震减灾对策提供新思路。 相似文献
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To improve the reliability of earthquake prediction, it is important to determine those layers in the crust of the earth in which the foci of most strong earthquakes occur. An analysis of regional earthquake catalogues shows that in depressions strong events originate within a specific layer in the middle part of the crust. An investigation of the geothermal regime in the depressions under study shows that the thickness and location of this layer depend on geothermal parameters which correlate with the strongest earthquake magnitude in particular areas. Thus, it seems possible to use geothermal and seismological parameters for estimating the maximum magnitude of earthquakes for at least some areas. 相似文献
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A new approach on numerical modeling of wave propagation is introduced and is used to analyze the effect of earthquake magnitudes (ground motion amplitudes) on wave propagation. In this method, the sum of the maximum amplitudes of the first output model at time 0 s and rest of the output models at different times are normalized to unity. Considering this as a constraint, the sum of the weighted‐squared Fourier amplitudes is minimized by using the Lagrange multiplier method. The proposed method can reveal the relationship of actual time histories by showing simple clear peaks. This method is used to analyze the time histories of various earthquake events at different vertical array sites of the Kashiwazaki–Kariwa nuclear power plant of Tokyo electric power company (TEPCO). The wave arrival times obtained from this method and down‐hole measurements are compared. The results show increase in the arrival times at surface layer when the magnitude of earthquake is large. The results reveal that the amplitudes of small magnitude earthquakes at depths are small and are largely amplified at surface, whereas in case of large magnitude earthquakes, the amplitudes are large at depths and are deamplified at surface reflecting the effects of the strain‐dependent soil properties that result in non‐linear site response to strong shaking. The results also show that the reflected peak amplitudes are higher for small magnitude earthquakes than for large magnitude earthquakes. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献