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地震进口窗：试论中国大陆及边邻强震活动关联性 总被引：4，自引：0，他引：4
本文在对我国边邻三个“地震进口窗”内M_s≥7.0级地震与中国内陆的部分M_s≥6.0级地震活动的时、空关系简述后,讨论了如何利用这种关系来预报中国内陆M_s≥6.0级地震的时、空问题,以期为大形势的趋势预报提供有益的参考.文末也对“地震进口窗”的物理意义进行了简单的讨论. 相似文献
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新疆的地震预报是1970年开始的。二十多年来在“边观测、边研究、边预报”、“多路探索、多兵种联合作战”、“走综合预报之路”的方针指导下取得了长足的进展。建设了43个地震台站,投入189套仪器,建成了遍布全疆的地震无线通讯网,开展了历史地震调查和地震烈度区划工作,建立健全了地震会商预报制度,进行了多方面的地震预报研究。实际地震预报统计分析表明,扣除自然发震概率之后,趋势预报的成功率约0.3,短临预报的成功率约0.1。在前兆台网控制范围内取得了一些震例,说明地震确实是有前兆的,但又是非常复杂的。地震预报作为科学难题还有漫长的路要走。作者简要地讨论了地震观测的间接性和地震异常的离散性、难以区别的地震异常和地壳变动异常、建立在复杂现象基础上的地震前兆以及地震的混沌性对地震预报的影响等科学问题。 相似文献
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如实记述了１９９５年度中国大陆及边邻ＭＳ≥７．０地震活动的时、空演变与华北（φＮ３０°～φＮ４２°，λＥ１０５°～λＥ１２５°）地震活动等有关的试验预报的实况。对过去的预报办法提出了一些改进意见。 相似文献
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一次地震预报有效性的"距准误差"评价法--中短期前兆及预报效能评价之一 总被引：5，自引：3，他引：2
一次地震预报有效性的评价是中短期前兆预报效能统计评分的基础。研究提出了基于误差概念的距准误差评价法(打靶模型)。以预报三要素(Ψ、λ可合为“地域”一个要素)的目标点为“准”,以准理想预报尺度围成的封闭区为“靶心”,以可容忍误差尺度为“靶径”。实际地震与目标点的距离(误差)小于准理想尺度,则地震预报击中“靶心”即为实现准理想预报(评分为1),以此向外逐渐扩大到可容忍误差尺度为止,误差超过此尺度即为“脱靶”(评分为0)。根据当前预报的实际水平,考虑了中期、短期和短临三类预报及预报震级的不同,分别给予准理想预报尺度和可容忍误差尺度的约定标准。实例证明方法有效可用。 相似文献
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"九五"我国地震地下流体研究的主要科学进展 总被引：6，自引：1，他引：6
总结了“九五”以来我国在地震地下流体研究方面的主要科学进展，从流体前兆成因、异常识别与预报技术，流体的作用与前兆机理和观测技术等方面的研究进展进行了归纳论述。还阐述了地震地下流体研究的科学发展问题。 相似文献
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"一主二辅"的预报思路 总被引：2，自引：1，他引：1
通过海域地震以来我国地震预报成功的三种类型实例和研究和基于前兆现象复杂性的分析,提出了现阶段中期－－短临预报可采用“一主二辅”的预报思路,即以地震活动为主,前兆异常现象为辅的预报途径。 相似文献
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一次地震预报有效性的"概率统计"评价法--中短期前兆及预报效能评价之二 总被引：3，自引：2，他引：1
该提出了评价一次地震预报有效性的概率统计法(套圈模型)。设预报4维空间中一个有限封闭的范围,实际地震落人其范围内即为“报准”,否则为“未报准”。在报准的情况下,预报区间的大小就反映预报水平的高低。这可用预报区域内地震发生的自然概率P来衡量。与“打靶模型”相似,“套圈模型”评价上限是准理想预报尺度,下限是可容忍误差尺度。根据不同的尺度,计算相应的概率。以相应概率对数值之差为比例计算评价值。实际算例表明,此方法与距准误差评价结果相当吻合。 相似文献
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邢台震情窗口的遥联性 总被引：2，自引：0，他引：2
通过邢台震情窗口的成组震兆与中国大陆及边邻大地震整体链式活动的对应关系，指出该“窗”具有遥联性的特点，它可能为我国大陆及边邻活动大形势作中期遥联预报或其它有关的研究工作提供有益的参考。文末对这种遥联现象的物理成因进行了初步讨论。 相似文献
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地震预测是世界公认的科学难题，本文对地震预测的难点作了简要分析，并指出其实质在于缺乏对地震发生规律性的认识。文中较详细地介绍了近些年来欧洲、日本、美国和俄罗斯在地震预测研究方面的进展。实际情况表明，国际上虽对地震预测研究还存在着种种不同意见，但地震预测研究仍在扎扎实实地取得进展，然而，要期望取得突破，尚需做出长期不懈的努力。 相似文献
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Tsuneji Rikitake 《Surveys in Geophysics》1972,1(1):4-26
A long-term research program on earthquake prediction in Japan, officially launched in 1965, has made progress. Many of the developments achieved in recent years in various disciplines are outlined. Some of the important findings include: detection of land-deformation by intensified levelling and geodimeter surveys, empirical relations between the extent of a premonitory land-deformation and the magnitude and occurrence-time, and the growth and decay of earthquake swarms accompanied by occurrences of large-scale earthquakes. Operations research on selection of survey areas for levelling and the location of crustal deformation observatories has been made.To process data for earthquake predictions, three centers for different disciplines were set up: in the Geographical Survey Institute, the Japan Meteorological Agency, and the Earthquake Research Institute (University of Tokyo). A newly established committee, called the Coordinating Committee for Earthquake Prediction, which consists of about 30 specialists, analyzes the data flowing into these three channels. The committee issues a warning of earthquake danger, whenever possible.A tentative strategy for achieving earthquake prediction is proposed. An attempt is made to evaluate ratings of earthquake threats on the basis of probability theory.An anomalous land-deformation was found in the South Kanto district, an area south of Tokyo, in 1969. following the strategy, an intensive effort, called Operation South Kanto, aiming at a possible prediction of large earthquakes is now under way. Judging from the results of various earthquake prediction elements, the probability of having an earthquake of magnitude 7 or there-abouts within a period of about 10 yr can not be low if anomalous land-deformation is related to the probability of earthquake occurrence. 相似文献
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随着川滇地区强震记录的不断增加,为了建立更符合该区域地震动特征的预测模型,文中基于该区域现有的地震动数据,通过随机效应回归模型建立适用于川滇地区的地震动预测模型;2021年5月21日,云南省大理州漾濞县发生6.4级地震,为了分析文中预测模型对漾濞地震的适用性,首先根据预测模型的适用范围选取合适的漾濞地震数据,计算真实记... 相似文献
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简述了地震预测的方法与类别, 回顾了20世纪70年代以来国内外几次重要地震预测预报实践特别是地震短临预测预报的情况, 从中凸显了地震短临预报的困难以及对挽救生命的重要性和社会需求的紧迫性. 通过对上述国内外一些大地震预报预测(海城地震、 唐山地震、 日本地震、 美国帕克菲尔德试验场的地震预报实践和汶川地震等)的成功与失败的解读, 试图得到一些有益的启示: 地震预测与预报, 尤其是地震短临预测与预报虽然困难, 但并不是不可能的, 事实说明它存在着很大的可能性. 相似文献
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M. S. Molodenskii S. M. Molodenskii D. S. Molodenskii T. A. Begitova 《Izvestiya Physics of the Solid Earth》2017,53(3):454-457
In (Molodenskii M.S. et al., 2016), the data from horizontal pendulums recording the tilts in the closest vicinity of the Great Tohoku earthquake of March 11, 2011 in Japan were analyzed. A significantly improved method for statistical analysis of the observational data enabled the authors to reveal a slow growth in tidal tilts during a period of six years before the earthquake, which was superseded by an instantaneous drop in the amplitudes at the time of the earthquake. After this, during the subsequent four years, the tidal amplitudes have remained at a significantly lower level than their average values before the earthquake. These changes in tidal amplitudes testify to the nonlinear character of the tidal response of the medium in the presence of large tectonic stresses: as is well known, the linear relationship between stresses and strains in a real medium is only the case for stresses that are far below the yield stress. When the stresses approach the failure limit, two counteracting effects come into play: (1) the shear moduli in some areas decrease as a result of the avalanche growth of the crack formation processes, and (2) the moduli increase due to the compression in the other areas. Irrespective of which particular effect of these two is predominant, in either case the linearity of the relationship between the stresses and strains should be violated. This violation cannot but affect the amplitudes of the tidal tilts and strains characterizing this relationship in the presence of fairly low additional tidal stresses (i.e., the derivative of the off-diagonal stress tensor components with respect to the same components of the strain tensor). Since there is presently a sufficiently dense network of the horizontal pendulums recording the tilts (the global IRIS network and the particularly dense F-NET network in Japan), monitoring the changes in the amplitudes of tidal tilts can be considered as a key instrument for capturing the signs of the approach of tectonic stresses to their critical values. The increase in tidal amplitudes before the Tohoku earthquake and their drop at the moment of the earthquake, which were revealed by us, as well as the constancy of the amplitudes during four years after the event, unambiguously indicate that the accumulation of tectonic stresses caused the growth in tidal amplitudes, whereas the stress release by the earthquake caused their diminution. This does not however mean that stress accumulation is accompanied by a decrease in the elastic moduli and that the release of stresses is accompanied by the growth of elastic moduli all over the source area. As was shown in (Molodenskii M.S. et al., 2012), even in the simplest model of spatially homogeneous variations of elastic modules, the variations in tidal tilts are an odd function of the distance from the epicenter. Therefore, irrespective of whether the elastic moduli decrease or increase, the amplitudes of tidal tilts should decrease in some areas and increase in other areas. Hence, the very fact of the growth of tidal tilt amplitudes with time cannot be considered as a sign of the growth of tectonic stresses. To be positive about the latter, one should make sure that the consistent (unidirectional) changes have been observed during a sufficiently long time interval and that their magnitudes were significantly larger than the measurement errors. Hence, it is important to reliably estimate the errors of the observational data. 相似文献
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回顾了我国 30多年来的地震现场震情监视预报工作。该工作从目标角度考虑大致可分为二个不同的阶段, 1980年前主要是地震预报方法的探索, 而 1980年以后,更主要的是承担地震预报的社会服务。对我国赴国外地震现场的工作情况作了概述, 并提出了地震现场震情监视预报工作的可能前景。 相似文献
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Two categories of earthquake precursors,physical and tectonic,and their roles in intermediate-term earthquake prediction 总被引：1，自引：0，他引：1
Katsuhiko Ishibashi 《Pure and Applied Geophysics》1988,126(2-4):687-700
I suggest that earthquake precursors can be divided into two major categories, physical and tectonic. I define physical precursor to be a direct or indirect indication of initiation or progression of an irreversible rupture-generating physical process within the preparation zone of a forthcoming earthquake. Tectonic precursor is defined as a manifestation of tectonic movement which takes place outside the preparation zone of an impending earthquake as a link in a chain of particular local tectonism in each individual area preceding the earthquake.Most intermediate-term, short-term and immediate precursors of various disciplines within the source regions of main shocks are considered physical ones. Some precursory crustal deformations around the source regions are, however, possibly tectonic precursors, because they may be caused by episodic plate motions or resultant block movements in the neighboring regions of the fault segments that will break. A possible example of this phenomena is the anomalous crustal uplift in the Izu Peninsula, Japan, before the 1978 Izu-Oshima earthquake ofM
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6.8. Some precursory changes in seismicity patterns in wide areas surrounding source regions also seem to be tectonic precursors, because they were probably caused by the particular tectonic setting of each region. A typical example is a so-called doughnut pattern before the 1923 Kanto, Japan, earthquake ofM
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8.2.Although most studies on earthquake precursors so far seem to regard implicitly all precursory phenomena observed as physical ones, the two categories should be distinguished carefully when statistical analysis or physical modeling is carried out based on reported precursory phenomena. In active plate boundary zones, where a practical strategy for earthquake prediction may well be different from that in intraplate regions, tectonic precursors can be powerful additional tools for intermediate-term earthquake prediction. 相似文献