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区域地震活动性诸多统计量之间各自的独立性或相关性分析是重要的，因这直接影响区域地震活动状态的分析、诸参量在综合强震预测中贡献的考虑，及各参量本身物理意义的认识。本文采用地震活动统计量，地震ｂ值、η值、活动度ｓ、活动标度△Ｆ、熵值θ￣Ｎ、θ￣Σ、β值等地震活动性时间序列的输出曲线，用相对变化斜率关联度、相对距离关联度和相似性关联度进行了研究，给出了活动性状态分析曲线簇之间强关联、弱关联和无关联的分析方法和结果。 相似文献
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通过对我国地震台网观测资料以及地震活动特征的分析，给出了处理中小地震活动性图象的网格点密集值计算方法．该方法综合考虑一定时空及震级范围内地震的数量和震中分布这两方面因素，并特别强调了计算参量的选取应充分考虑资料精度的影响．应用该方法得到的地震活动性图象能够准确、合理地反映地震活动特征并具有较好的稳定性．经该方法处理的图象是对地震活动性进行定量分析的基础，在地震趋势分析、中长期地震预测以及防震减灾等方面有很好的应用前景． 相似文献
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依据震中迁移、频度变化曲线、能量释放曲线、震级频度关系和时间序列的预测方法等,对陕西地区的地震活动性进行了初步分析,认为:陕西地区M_L>3.5级的地震活动存在着明显的由北向南、自东向西的迁移特点,其地震活动水平比较正常,今后5年内可能发生M_L≥4.3级地震。 相似文献
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从各种地震活动性参数的解析表达式入手,分析了诸参数对地震活动强度和频度的依赖性和相关性．一类为区域地震活动性统计参数,文中共分析了17个;另一类为地震活动分布类参数,即时间、空间、震级分布类参数．分布类参数的存在基础及合理性在于其分布模型的适用性．文中对地震时间、空间、震级的自然概率分布、泊松分布、威布尔（Weibull）分布和分形的解析式进行了形式类比和分析,并以实例说明．对余震序列衰减系数P值、H值、震群序列U值、F值和熵值K也作了初步评价,并给出了评价地震活动性参数之间相关性的另一途径,即分析计算输出时序曲线之间的关联度．文中推荐相似性关联度RY1Y2和相对变化斜率关联度GY1Y2作判定量．最后就众多地震活动性参量的筛选与应用提出了初步看法． 相似文献
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论述了断层地表永久位移概率地震危险性分析方法的发展过程和应用现状,指出了断层地表破裂预测模型研究的意义。根据我国最近的活动断层地表破裂震后调查结果,基于走滑型断层地表破裂数据,拟合了地表破裂预测模型。采用地震活动性模型和地表破裂预测模型,计算了则木河断裂地表迹线上的永久位移危险性曲线,对预测模型在工程场地地震危险性分析中的应用,提出了建议。 相似文献
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从分析地震活动性参数变化特征的角度出发,结合实际的地震活动观测资料,对张北６．２级地震前河北省及邻区地震活动性参数的变化,地震序列的衰减特征进行了分析,结果表明张北６．２级地震前在震源区附近１００ｋｍ和大范围地震活动性参数有长、中、短期的异常变化。张北６．２级地震强余震前地震活动性参数有短、临变化。 相似文献
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The most complete and reliable data of strong (M
s6.5), shallow (h<70 km) earthquakes which occurred in the inner Aegean seismic zone have been utilized to describe its seismicity time variation during 1800–1986 by two independent statistical models. The first is a sequentially stationary model of seismicity rates which shows that intervals of low seismicity rate, lasting for some 37 years, alternate with high rate intervals of 8–12 years duration. The second model is a statistical model according which seismic energy released within 5-year time windows approximates a harmonic curve within a period of about 50 years. This model is in agreement with the notion that the time series of strong earthquake occurrences in the inner Aegean seismic zone consists of a random (shocks withM
s=6.5–6.8) and a nonrandom component (M
s6.9). Maxima and minima of the harmonic curve coincide with the high and low rate intervals, respectively. A model of regional stationary accumulation of thermal stresses along certain seismic belts and their cyclic relaxation may explain this periodicity. 相似文献
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Research on the principle and methodology of seismic zonation 总被引：1，自引：0，他引：1
Based on the cognizance of the temporal-spatial inhomogeneity of seismicity in North China, adopting the results of earthquake prediction in the past two decades and the currently used methods of seismic hazard analysis, and after some zonation trials in North China, some improvements on the zonation principle and methodology were made:
- Seismic zones were taken as statistic units where seismicity parameters were obtained. Tendency analysis was introduced. Earthquake annual average occurrence rates were estimated corresponding to the seismicity level in the future period;
- Average annual earthquake occurrence rates for a given magnitude interval of a specific seismic zone were assigned to potential sources considering the relative risk level among these sources. Thus, the risk of great earthquakes can be estimated.
- The probabilistic spatial distribution function under the condition of magnitude interval was suggested to reflect the temporal and spatial inhomogeneity of seismicity.
- An orientation function in the seismic hazard analysis model was adopted, which reflects the real condition of earthquake foci in China.
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The Pattern Informatics (PI) technique (tiampo et al., 2002) is founded on the premise that changes in the seismicity rate are a proxy for changes in the underlying stress. These stress changes are correlated over large spatial regions, and can be quantified using a phase dynamical analysis of the changes in historic seismicity rates. This new approach to the study of seismicity quantifies its local and regional space-time patterns and identifies regions of local quiescence or activation. Here we study those local changes in an attempt to objectively quantify short-term stress shadow regions. We determine that, while persistent stress shadows are detectable with this method, they do not occur uniformly throughout the spatio-temporal region. 相似文献
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鲜水河断裂带地震活动特征及强震发生随时间增长概率 总被引：3，自引：0，他引：3
作者等仔细分析了鲜水河断裂带从１７２５年到现在的地震资料，并利用乌莫洛夫Ｔ─Ｓ、Ｍ为参数的作图法及强震发生随时间增长概率，绘制了地震活动图件及地震发生概率曲线以及Ｍ─Ｔ图和鲜水河断裂应变释放曲线。根据这些资料可以清楚地看出鲜水河断裂带自１７２５年到现在可分为两个大的活动周期，其中６．０级以上地震有由康定依次向甘孜迁移的特点。在每一个大的地震活动周期中，地震基本上两次重复由康定向甘孜迁移的过程，而且较强地震多发生在第二次迁移过程中，１９８２年甘孜地震标志着断裂带在第二幕地震活动高潮中，中强震已经完成了最后一次由断裂带东南端向西北端迁移的过程。同时考虑到断裂带应变释放曲线的特征，估计鲜水河断裂带目前已进入新的平静阶段。前两个大的活动周期之间，平静了近一个世纪。按历史上地震定向迁移规律，估计在新的活动期地震仍将从康定方向开始，逐步向甘孜发展。 相似文献
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G. A. Sobolev N. A. Zakrzhevskaya D. G. Sobolev V. A. Petrov 《Journal of Volcanology and Seismology》2017,11(2):103-112
This study is concerned with the influence exerted by worldwide M ≥ 7.5 earthquakes on the seismicity of California, and well as with the effects of M ≥ 5 southern California earthquakes on northern Californian seismicity. The analysis concerns the 1990–2013 period. We noted a seismicity increase in southern and northern California during the first 24 hours after worldwide earthquakes and a decrease during the next 48 hours. A seismicity increase in northern California during the first 24 hours following an earthquake in southern California and a decrease during the next 48 hours were also noted. A seismicity increase was observed in the Long Valley caldera during the first 24 hours following an M ≥ 5 earthquake in southern California and a decrease during the next 48 hours. We also discuss some causes of this trigger effect, in view of the fact that the external excitations had low intensity. No seismicity changes have been detected in southern and northern California during powerful typhoons in the northeastern Pacific and during magnetic storms. 相似文献
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Precursory seismic quiescence: Past,present, and future 总被引：4，自引：0，他引：4
R. E. Habermann 《Pure and Applied Geophysics》1988,126(2-4):279-318
Precursory seismic quiescence has played a major role in most of the succesful earthquake predictions made to date. In addition to these successes, the number of detailed post-mainshock documentations of precursory quiescence is steadily growing. These facts suggest that precursory quiescence will play an important role in earthquake prediction programs of the future. For this reason it is important to critically evaluate the present state of knowledge concerning this phenomenon. The history of observations of precursory seismic quiescence includes work on seismic gaps and seismic preconditions as well as actual studies of temporal quiescence. These papers demonstrated the importance of quantitative evaluation of seismicity rates and the benefits of systematic analysis. During the early 1980's the impact of man-made effects on seismicity rates was demonstrated for the first time. Despite progress in catalog understanding, the identification and correction of man-made seismicity changes remains as the major barrier to earthquake prediction using these data. Effects of man-made changes are apparent in many past studies of seismicity patterns, making the results difficult to evaluate. Recent experience with real-time anomalies has demonstrated the necessity of determining the false alarm rates associated with quiescence precursors. Determination of false alarm rates depends on quantitative definitions of anomalies and statistical evaluations of their significance. A number of successful predictions, which have been made on the basis of seismic quiescence, provide important lessons for present and future work. There are many presently unanswered questions regarding seismic quiescence which must be answered before we can determine the reliability of this phenomena as a precursor. 相似文献
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本文讨论了广西河池地区地震活动的时空分布、应力场“窗口”效应和小震级高烈度等特征,並利用岩石实验的某些结果对该区地震的发震机制作了一些定性解释。该区是一个两组断裂交汇的应力敏感区,地震是在低应力条件下在极不均匀介质宁原有裂隙发生粘滑的结果,其特殊的地体环境下可能构成蕴育大震的条件,其地震活动不会对邻近的龙滩库坝区造成威胁。 相似文献
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In this study, the seismic quiescence prior to hazardous earthquakes was analyzed along the Sumatra-Andaman subduction zone (SASZ). The seismicity data were screened statistically with mainshock earthquakes of M w?≥?4.4 reported during 1980–2015 being defined as the completeness database. In order to examine the possibility of using the seismic quiescence stage as a marker of subsequent earthquakes, the seismicity data reported prior to the eight major earthquakes along the SASZ were analyzed for changes in their seismicity rate using the statistical Z test. Iterative tests revealed that Z factors of N?=?50 events and T?=?2?years were optimal for detecting sudden rate changes such as quiescence and to map these spatially. The observed quiescence periods conformed to the subsequent major earthquake occurrences both spatially and temporally. Using suitable conditions obtained from successive retrospective tests, the seismicity rate changes were then mapped from the most up-to-date seismicity data available. This revealed three areas along the SASZ that might generate a major earthquake in the future: (i) Nicobar Islands (Z?=?6.7), (ii) the western offshore side of Sumatra Island (Z?=?7.1), and (iii) western Myanmar (Z?=?6.7). The performance of a stochastic test using a number of synthetic randomized catalogues indicated these levels of anomalous Z value showed the above anomaly is unlikely due to chance or random fluctuations of the earthquake. Thus, these three areas have a high possibility of generating a strong-to-major earthquake in the future. 相似文献