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地震活动性中心Ｇｕｔｅｎｂｅｒｇ－Ｒｉｃｈｔｅｒ关系（ｌｏｇＮ＝ａ－ｂＭ）在确定地震发生率时起着重要作用，实际分析中存在的对Ｇ－Ｒ关系的偏离主要是由于地震目录的不完全性引起：即在低震级端因地震的监测能力有限，在高震级端因大震的稀少导致的统计涨落。 相似文献
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对湖南及其邻区7°×7°范围内的历史有感地震进行了分析,按照C-R关系推测,研究区自1509年起肘≥31/2地震目录基本完整.研究区现代地震活动水平较弱,而破坏性地震不仅发生的周期较长,且频次较低,在地震活动性研究中很难将现代小震与历史破坏性地震合理地结合起来.考虑了较为完整的有感地震目录后,地震活动性参数统计样本量显著增加,b值拟和的相关系数提高了,拟和方差降低了,拟和结果也更加合理,年发生率v4的计算也变得更为合理.同时发现,较强历史有感地震的空间分布与深部构造有密切关系.该研究成果对研究区地震安全性评价和地震区划具有参考价值. 相似文献
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地震统计区地震活动性参数b值及v4不确定性研究 总被引：5，自引：1，他引：5
本文结合华北地区几个地震统计区的实例，探讨了地震统计区的重要地震活动性参数b值和v4不确定性的主要影响因素及其特征，并研究分析了其不确定性的大小。结果表明，地震活动性参数的不确定性主要影响因素为样本统计时段、样本处理方法、统计下限震级、高震级年平均发生率等。在郯庐地震统计区，b值变化可达0．2以上，v4的变化可达1．4以上，汾渭地震统计区的不确定性也基本相当，河北平原地震统计区因为地震样本相对丰富，不确定性要小许多。 相似文献
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本文利用最大熵原理计算了山西地震带(1200—1989年)中强震分震级档的年平均发生率。利用综合概率法根据地震活动性的多次指标计算了各潜在震源区的空间分布函数,把空间分布函数作为权系数将山西地震带中强震分震级档的年平均发生率向各潜在震源区分配,可得到各潜在震源区分震级档的年平均发生率和平均重现期。对震级M的概率密度函数f_M(m)的x~2检验表明,在水平0.25时通过x~2检验。作为应用实例,计算了临汾盆地M≥5.5地震的年平均发生率和平均重现期,内符检验表明,理论值和实际发生地震数符合得较好。 相似文献
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基于1990-2016年中国地震台网地震目录中面波震级和全球矩心矩张量（GCMT）项目的矩震级数据，使用加权最小二乘法，给出中国地震台网面波震级与矩震级的统计关系，分析该统计关系与实际数据之间的残差分布，并将其与已有统计关系进行对比，结果表明，本研究所得统计关系式具有较好的无偏性，更能体现中国地震台网面波震级与矩震级的对应关系。 相似文献
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地震活动性参数b值和年发生率的一种取值方法 总被引：1，自引：0，他引：1
介绍了一种将历史地震与现代小震统计结果相协调,去不可靠或不稳定数据段确定地震活动性参数ｂ值,以及通过不同震级下限地震频度的时间滑动分析,选取现今与历史相近,且具较高震级下限的统计结果,推算４级以上地震年发生度ｖ４的方法。计算给出了东南沿海地震带及其南带,北带的ｂ值和ｖ４值。 相似文献
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利用活动断裂定量研究资料（滑动速率、古地震等）,结合新疆地区的地震构造环境特征分析,研究了典型潜在震源区大震复发模式,建立了具有区域特征的混合模型,以此评定了新疆地区典型潜在震源区大震的年发生率。混合模型由截断G-R关系模型和特征地震模型构成,计算时先分别计算两个模型的大震分震级档年发生率,然后根据潜在震源区地震地质资料的完备性情况、可靠程度以及大震孕育的区域性特征为两个模型的分震级档结果赋予一定权重,最后求两个模型的加权和。大震复发间隔的计算中利用汶川地震与集集地震的最大垂直位错和平均垂直位错统计关系约束了逆冲型断裂的平均位错量,潜源区的大震年发生率的计算考虑了级联破裂问题。结果表明,本研究所得高震级档大震年发生率比第三代、第四代地震区划图小,文中对这一现象产生的原因进行了初步分析。 相似文献
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Introduction At present, the current probabilistic method of seismic hazard analysis in the world is gener-ally adopted in seismic safety evaluation (Cornell, 1968). It supposed that earthquake occurrence conforms to the segmented Poisson distribution model in time and space and the proportional rela-tion among earthquakes of various magnitudes obeys the cut-exponential distribution law in a sta-tistical area in compiling Seismic Intensity Zoning Map in China (1990) owing to the temporal- sp… 相似文献
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发震构造特性是潜在震源区划分及其地震年发生率确定的重要依据。潜在震源区除了反映“未来具有发生破坏性地震的地区”的内涵外,还应反映高震级档地震具有相似复发特征的涵义。由于在地震活动性参数统计单元内,有一些具有不同本底地震的活动构造块体,为更好地反映地震活动的空间不均匀性,考虑潜在震源区的三级划分是有必要的。通过分析潜在震源区内高震级档地震的复发特征,计算预测时段内潜在震源区的高震级档地震的发震概率,采用预测时段内概率等效转换获得地震年平均发生率的方法,有助于在中国地震危险性分析框架内考虑潜在震源区的强震复发特性。另外,文中还对潜在震源区内特征地震次级震级档频度不足的特性和发震构造上强震非均匀性在地震危险性分析中的应用问题进行了探讨 相似文献
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UNIFIED EARTHQUAKE CATALOG FOR CHINA’S SEAS AND ADJACENT REGIONS AND ITS COMPLETENESS ANALYSIS 
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下载免费PDF全文 China’s seas and adjacent regions are affected by interactions among the Eurasian plate, the western Pacific plate, and the Philippine Sea plate. Both intraplate and plate-edge earthquakes have occurred in these regions and the seismic activities are frequent. The coastal areas of China are economically developed and densely populated. With the development and utilization of marine energy and resources along with the development of national economy, the types and quantity of construction projects in the marine and coastal areas have increased, once an earthquake happens, it will cause huge damage and loss to these areas, therefore, the earthquake-related research for these sea areas cannot be ignored and the need for study on these areas is increasingly urgent. One type of essential basic data for marine seismic research is a complete, unified earthquake catalog, which is an important database for seismotectonics, seismic zoning, earthquake prediction, earthquake prevention, and disaster reduction. Completeness and reliability analysis of an earthquake catalog is one of the fundamental research topics in seismology.
At present, four editions of earthquake catalogs have been officially published in China, as well as the earthquake catalogue compiled in the national fifth-generation earthquake parameter zoning map, these catalogs are based on historical data, seismic survey investigations, and various instrumental observations. However, these catalogs have earlier data deadlines and contain the earthquake records for only the offshore regions of China, which are extensions of coastal land. Distant sea regions, subduction zones, and adjacent sea regions have not been included in these catalogs. Secondly, there were no cross-border areas involved in the compilation of earthquake catalogs in the past. It was not required to use magnitudes measured by other countries’ seismic networks and observation agencies to develop an earthquake catalog with a uniform magnitude scale, moreover, there was no formula suitable for the conversion of magnitude scale in China’s seas areas and adjacent regions. Little research has been conducted to compile and analyze the completeness of a unified earthquake catalog for China’s seas and adjacent regions. Therefore, in this study, we compiled earthquake data from the seismic networks of China and other countries for China’s seas and adjacent regions. The earthquake-monitoring capabilities of different sea areas at different time periods were evaluated, and the temporal and spatial distribution characteristics of epicentral location accuracy for China’s seas and adjacent regions were analyzed. We used the orthogonal regression method to obtain conversion relationships between the surface wave magnitude, body wave magnitude, and moment magnitude for China’s seas and adjacent regions, and established magnitude conversion formulae between the China Seismic Network and the ML magnitude of the Taiwan Seismic Network and the MS magnitude of the Philippine Seismic Network. Finally, we developed an earthquake catalog with uniform magnitude scales for China’s seas and adjacent regions.
On the basis of the frequency-magnitude distribution obtained from the magnitude-cumulative frequency relationship (N-T) and the Gutenberg-Richter(GR)law, we conducted a completeness analysis of the unified earthquake catalog for China’s seas and adjacent regions, Then, we identified the beginning years of each magnitude interval at different focal depth ranges and different seismic zones in the earthquake catalog.
This study marks the first time that a unified earthquake catalog has been compiled for China’s seas and adjacent regions, based on the characteristics of seismicity in the surrounding sea regions, which fills the gap in the compilation of the earthquake catalogue of China’s seas and adjacent areas. The resulting earthquake catalog provides a basis for seismotectonics, seismicity study, and seismic hazard analysis for China’s seas and adjacent regions. The catalog also provides technical support for the preparation of seismic zoning maps as well as for earthquake prevention and disaster reduction in project planning and engineering construction in the sea regions. In addition, by evaluating the earthquake-monitoring capability of the seismic networks in China’s seas and adjacent regions and analyzing the completeness of the compiled unified earthquake catalog, this study provides a scientific reference to improve the earthquake-monitoring capability and optimizing the distribution of the seismic networks in these regions. 相似文献
At present, four editions of earthquake catalogs have been officially published in China, as well as the earthquake catalogue compiled in the national fifth-generation earthquake parameter zoning map, these catalogs are based on historical data, seismic survey investigations, and various instrumental observations. However, these catalogs have earlier data deadlines and contain the earthquake records for only the offshore regions of China, which are extensions of coastal land. Distant sea regions, subduction zones, and adjacent sea regions have not been included in these catalogs. Secondly, there were no cross-border areas involved in the compilation of earthquake catalogs in the past. It was not required to use magnitudes measured by other countries’ seismic networks and observation agencies to develop an earthquake catalog with a uniform magnitude scale, moreover, there was no formula suitable for the conversion of magnitude scale in China’s seas areas and adjacent regions. Little research has been conducted to compile and analyze the completeness of a unified earthquake catalog for China’s seas and adjacent regions. Therefore, in this study, we compiled earthquake data from the seismic networks of China and other countries for China’s seas and adjacent regions. The earthquake-monitoring capabilities of different sea areas at different time periods were evaluated, and the temporal and spatial distribution characteristics of epicentral location accuracy for China’s seas and adjacent regions were analyzed. We used the orthogonal regression method to obtain conversion relationships between the surface wave magnitude, body wave magnitude, and moment magnitude for China’s seas and adjacent regions, and established magnitude conversion formulae between the China Seismic Network and the ML magnitude of the Taiwan Seismic Network and the MS magnitude of the Philippine Seismic Network. Finally, we developed an earthquake catalog with uniform magnitude scales for China’s seas and adjacent regions.
On the basis of the frequency-magnitude distribution obtained from the magnitude-cumulative frequency relationship (N-T) and the Gutenberg-Richter(GR)law, we conducted a completeness analysis of the unified earthquake catalog for China’s seas and adjacent regions, Then, we identified the beginning years of each magnitude interval at different focal depth ranges and different seismic zones in the earthquake catalog.
This study marks the first time that a unified earthquake catalog has been compiled for China’s seas and adjacent regions, based on the characteristics of seismicity in the surrounding sea regions, which fills the gap in the compilation of the earthquake catalogue of China’s seas and adjacent areas. The resulting earthquake catalog provides a basis for seismotectonics, seismicity study, and seismic hazard analysis for China’s seas and adjacent regions. The catalog also provides technical support for the preparation of seismic zoning maps as well as for earthquake prevention and disaster reduction in project planning and engineering construction in the sea regions. In addition, by evaluating the earthquake-monitoring capability of the seismic networks in China’s seas and adjacent regions and analyzing the completeness of the compiled unified earthquake catalog, this study provides a scientific reference to improve the earthquake-monitoring capability and optimizing the distribution of the seismic networks in these regions. 相似文献
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To actually reflect the seismic temporal-spatial inhomogeneity of intra continental strong earthquakes of North China in seismic
hazard analysis, several seismological and geological characteristics have been selected and quantized to describe the seismicity
features in time and space of every magnitude interval with the thought of dividing the interesting magnitude range into several
intervals and using of spatial probability distribution function. A component analysis method with orthogonal transformation
is introduced to avoid the repeated use of the same element and the subjective effects in determining the annual earthquake
occurrence rates of earthquake. By passing synthetic fuzzy judgement on the nonintercorrelated new characteristics, the annual
occurrence rates of every magnitude interval of each potential source area are obtained associated with the adjustments of
earthquake reducing process after the occurrence ofM>7 quake. An intensity map of the Beijing-Tianjin-Zhangjiakou area is calculated as an example which shows a close coincidence
with the seismic temporal-spatial inhomogeneity of North China.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 496–504, 1991. 相似文献
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通过回顾甘肃省近20多年的地震预报工作,发现年尺度地震预报成功率不足8％。分析了年尺度地震预报成功率低下的原因和提高年尺度地震预报成功率在实现具有减灾实效地震预报的目标中的重要意义。最后提出了在对甘肃及邻区地震构造环境、地球物理场和地震资料搜集、整理和分析的基础上,探讨其与强震活动的关联性,寻找地震发生的时、空、强分布规律,建立具有明确构造物理含义的地震预测模型,先进行长期地震危险性分析,再开展年尺度的地震跟踪预报的新思路。沿用这一思路,预期可以减少虚报,进而提高年尺度地震预报成功率。 相似文献
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中国目前实行的区域地震台网独立运行机制，使得在相邻不同台网的交界地区可能存在多个版本的地震目录和震相观测报告，影响了地震活动性分析与研究.为此，本文提出了一种基于联合概率的方法，可标明两个或多个相邻台网目录中相同的事件，合并它们的震相数据开展重新定位，并重构不同台网交界地区的统一地震目录.该方法的思路与分析步骤是：首先，计算获得不同台网之间具有最小发震时刻差异的两两地震的时空强差异分布，查找并剔除独立地震，计算事件合并的联合概率；其次，基于联合概率分析合并不同台网的地震目录和震相观测报告，对合并事件进行重新定位和定位误差分析，并基于G-R关系检验重构目录的完整性.本文以2014年鲁甸地震序列为例的初步应用结果显示，震相合并之后的地震定位精度相比之前单个台网的结果，特别是相比四川台网的目录，定位精度提高非常显著，合并后的目录与之前相对完整的云南目录接近，但相比由两个台网目录简单拼凑而成的目录更加准确.此外，研究还发现在目录合并过程中，对于4级以上的中强震，应选择MS而不是以ML震级标度；震相合并后被复用台站记录的到时信息可用于检测不同台网间的震相拾取是否存在系统偏差.本文提出的方法使得在相邻不同台网的过渡区形成一个统一且尽可能准确可靠的地震目录成为可能. 相似文献
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地震目录资料是进行地震预测、地震危险性分析、地震活动性研究等地震学研究的基础资料.对地震目录资料的完整性可靠性分析是地震学研究的基础工作之一.近几十年来我国积累的大量的仪器地震记录,历史地震也在不断更新,为地震活动性研究提供了更为丰富的样本,因此有必要对新的地震目录进行完整性分析.本文采用了新的统计方法对我国仪器记录地震目录和历史破坏性地震目录进行了完整性分析.结果表明,对于仪器记录地震目录（M≥3.0）我国东部地区1975年后基本完整,西部地区1980年后基本完整.对于历史地震目录（M≥5.0）,东部地区1500年后基本完整,西部地区1950年后基本完整.考虑到华北地震区历史破坏性地震（M≥43/4）活动的时间非平稳性,我们采用突变点分析法研究了华北地震区历史破坏性地震目录的时间特征,得到了华北地震区地震活动周期性变化的突变点位置,并揭示了华北地震区历史破坏性地震目录完整起始时间约为公元1500年前后. 相似文献
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利用１９７０～１９９４年华北地区仪器记录到的地震目录，通过层次模型，将该地区分为不同大小的单元，在每个单元中，由小震活动情况，通过Ｇ－Ｒ关系是到较大地震的活动情况；并根据震级和烈度之间的关系，得到未来５０ａ不同地震烈度的发生概率，文中还将所得结果与历史地震活动情况以及第三代区划图进行对比研究，结果表明，由近代小震活动对地震危险性进行评估是可能的。 相似文献
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川滇菱形块体及其边界断裂带(21°～33°N,96°～108°E)是中国大陆地震活动最强烈的地区之一,该地区发生的一系列大地震造成了巨大的人员伤亡和财产损失。文中分别应用基于地震空间相关性和地壳形变场的预测方法分析了该地区未来的地震危险性。由Kagan等(1994)提出的基于地震空间相关性的方法,假定未来发生地震的概率与历史发生地震的频度成正比,根据历史地震目录建立统计学模型估计未来发生地震的概率。回溯性检验表明,这种方法对于评估地震复发周期较短的断裂带的地震危险性有较高的有效性,但对于地震复发周期较长的断裂带,如龙门山断裂带,很难给出一个理想的预期。由Shen等(2007)提出的基于地壳形变场的方法,假定长期地震危险性与地壳构造应变率成正比,根据由GPS观测获得的应变率场建立统计学模型评估未来的地震危险性。回溯性检验表明,川滇地区过去30a间发生的地震与区域应变率的大小没有明显的对应关系,但过去500a间发生的地震与应变率场有很高的相关性,表明由10a时间尺度的大地测量资料得到的地壳应变场可以很好地反映数百a时间尺度的地震危险性。 相似文献