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中国地震历史资料的信息开发与利用 总被引:7,自引:1,他引:7
本文对全国历史地震资料的有用信息作了进一步的开发和利用,按统一方法处理了大量有感以上地震的文字记载,确字每个独立地震的时间与地点;分区求得地震的有感区长半径与震级的关系式;确定了历史有感地震的最低震级为4;取得了8000余次有感地震垢基本参数;用等震线测定了巨大地震的参数;将有感强震目录统编成全国与几个大区M≥4.0地震目录,按《地震学地震预报实用程序系统》(EPSEIS)的格式要求建库;同时编制 相似文献
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利用历史地震和现代小地震资料(其中包括少数有感地震)分析区域地震活动图象的文章已屡见不鲜,然而专门分析有感地震区域特征的文章尚未见到。这是由于历史上的有感地震是根据有关史料记载分析的结果,精度低,难于分析其区域特征;而现代有感地震资料的积累受到时间的限制,尚未取得一定数量的资料。本文对山东地区近十多年的有感地震进行了搜集整理,并研究其区域地震活动图象,发现其规律性远比相近震级范围的无感地震图象强,从而加深了对本区地震活动格局的认识。有关同一震级范围有感地震与无感地震图象的差异以及有感地震的宏观研究等方面的问题将另作讨论。 相似文献
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本文整理了湖北地区近26年来的202次地震资料,从中判别出138次有感地震.分析了这些地震的时间、空间和频度的演变特点,结果表明:1.区内现代有感地震活动西强东弱,三峡地区最强;2.震中多沿断裂带分布,断裂交汇部地震尤其活跃;3.以往划出的11个地震危险区中的竹溪、黄冈和麻城三个历史强震区于最近26年没有发生有感地震,此三区目前应当处于地震活动的平静期. 相似文献
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湖南省境内现今仪器记录地震约有1/5的地震有感,M_L≥2.7级的地震基本都有感。这些有感地震分布在东经111°以东地区,呈一向北张口的马蹄形分布,与当地地壳深部的马蹄形构生吻合,湖南省地震震级~烈度统计关系为M=0.93I_0-0.78,所有现今有感地震全部听到地声。 相似文献
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以无震时期细菌群落及水文化学元素信息为背景,阐明有感地震时的泉水细菌群落映震特征. 2010年12月——2011年4月,乌鲁木齐周边先后发生了MS3.1和MS3.6两次有感地震.本文采用末端限制性片段长度多态性法(T-RFLP)分析了该时间段内乌鲁木齐10号泉中细菌群落结构、多样性、稳定性、优势类群及特殊类群变化特征.结果表明,水文地球化学指标对有感地震不敏感,泉水细菌群落结构稳定,地震对其优势类群及多样性影响均不显著,但无震时期部分类群(以82,170, 176, 462 bp为代表)在前后两次地震中丰度变化趋势相似,即震前有小幅上升,震后1——12天内出现极大值,之后丰度逐渐恢复至较低水平,且表现出与震级、震中距具有一定相关性.这表明部分泉水细菌对有感地震映震灵敏. 相似文献
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在吸收历史地震研究、历史政区地理研究等多方面成果基础上,基于历史有感地震记载特点,探索了历史有感地震目录的编制原则,给出了地震日期、震中位置、震级的确定方法。以《中国地震历史资料汇编》等为依据,编制了公元前618年-公元1949年期间中国境内3≤M<443/4级历史有感地震目录9 121条。目录数量为中国同期文字记载的43/4级以上破坏性地震的7倍多,比全球其他国家或地区最早的同类目录早1 695年,约占全球同期M≤4.5级有感地震目录的2/3。 相似文献
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《Advances in water resources》2005,28(7):701-710
The patterns of temporal variations of precipitation (P), streamflow (SF) and baseflow (BF) as well as their nitrate-nitrogen (nitrate) concentrations (C) and loads (L) from a long-term record (28 years) in the Raccoon River, Iowa, were analyzed using variogram and spectral analyses. The daily P is random but scaling may exist in the daily SF and BF with a possible break point in the scaling at about 18 days and 45 days, respectively. The nitrate concentrations and loads are shown to have a half-year cycle while daily P, SF, and BF have a one-year cycle. Furthermore, there may be a low-frequency cycle of 6–8 years in C. The power spectra of C and L in both SF and BF exhibit fractal 1/f scaling with two characteristic frequencies of half-year and one-year, and are fitted well with the spectrum of the gamma distribution. The nitrate input to SF and BF at the Raccoon watershed seems likely to be a white noise process superimposed on another process with a half-year and one-year cycle. 相似文献
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燕郊等测点迁移优化与地磁观测研究 总被引:1,自引:2,他引:1
为优化地磁观测条件,开展了燕郊、夏垫等测点迁移工作;按照测眯迁移原则与实施技术方案,完整地收集并整理了地质构造与地球物理等方面的基本资料;进行了野外实地勘察,磁场梯度的测量,确定了新测点,在新老测点上进行了较长时间的地磁场对比观测;应用多种方法分析研究了地磁对比观测资料,结果表明,新老测点与有关测点的地磁变化具有良好的一致性,并得到了新老测点之间的地磁数据的按点差。 相似文献
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We rederive and generalize hyperbolic moveout formulae for the common-midpoint (CMP) gather and for the zero-offset (ZO) section that can be efficiently used for macro-model-independent reflection imaging in two-dimensional media. The hyperbolic moveout formulae for the common-midpoint gather are obtained from different Taylor series expansions of a particular parametric moveout surface defined in the multicoverage data space. Such a moveout surface involves three kinematic wave-field attributes of two hypothetical waves, which have to be determined by a coherency analysis. By using hyperbolic moveout curves in the CMP gather and in the ZO section one can determine these attributes in two steps. The relationships between the local shapes of the interfaces and the attributes of the hypothetical wave-fields attributes are considered by means of geometrical optics. The determination of these attributes allows to perform a macro-model-independent ZO simulation and a subsequent inversion. 相似文献
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Vindell Hsu Charles E. Helsley Eduard Berg David A. Novelo-Casanova 《Pure and Applied Geophysics》1984,122(6):878-893
A close correlation in spatial distribution of local seismic activity and energy release patterns before and after the 1979 Petatlan, Mexico earthquake suggests heterogeneity within the fault plane of this major low-angle thrust event associated with subduction along the Middle America Trench. A simple two-asperity model is proposed to account for the complexity. Foreshocks and aftershocks of the neighboring 1981 Playa Azul earthquake showed a similar pattern. As both events occurred at the junction of the Orozco Fracture Zone and the Middle America Trench, we speculate that the observed complex fault plane is caused by subduction of the rugged ocean floor of the Orozco Fracture Zone. Short-term precursory seismicity prior to the Petatlan earthquake can be explained by using the asperity model and migration of a slip front from the south-east to the north-west across the main shock source region. 相似文献
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Summary This paper discusses the influence of system stiffness on the dynamic instability of fault surfaces under laboratory conditions for a number of test modes. In conjunction with shear load stiffness, the normal load stiffness, often neglected, is shown to have a considerable effect on the stick-slip process —its presence or absence and its characteristics. Also appropriate stiffnesses are suggested for an earthquake sequence modeled as a growing dislocation. 相似文献