共查询到19条相似文献，搜索用时 118 毫秒
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澜沧—耿马地震的破裂过程 总被引：7，自引：0，他引：7
本文收集了国内各个单位和国外EDR报告给出的澜沧——耿马地震的震源参数和震源机制解参数,讨论了它们之间差别的原因。由地震定标律给出了主震7.5级地震的断层长度、宽度、面积和平均错距的估计值,结果分别为52 km,26 km,1.3×10~3 km~2,2.0 m。研究了它们的破裂方向:像是从中间地区分别向东南(产生最大主震7.5级地震)和西北方向(产生次大主震7.0级地震)破裂扩展,但不是同时,相隔了约13分钟。本文还讨论了第二次主震(Ms7.0)比第一次主震(Ms7.5)造成的地面破坏面积大的原因。 相似文献
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顾及先验信息的模型参数反演——澜沧—耿马地震位错模型参数的求定 总被引：7，自引：0，他引：7
采用澜沧－耿马地震前后两期大地测量资料，结合发震区的地质资料和震后地表形变破坏带的调查资料，运用顾及参数先验信息的贝叶斯反演方法，联合求定了澜沧－耿马地震的两个发震断层的位错模型参数，由反演后的位错模型推算的地震应力降同用地震波燃料的估算的应力降属同一量级。 相似文献
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澜沧—耿马地震震源动力学参数研究 总被引：8，自引：5，他引：8
本文使用沧澜—耿马地震主震后在震区建立的数字地震仪记录,用波谱法测算澜沧—耿马余震的震源动力学参数。就这些参数的统计特征,对该双主震型两主震区的地下介质不同状态予以讨论。 相似文献
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澜沧、耿马地震序列图象与发震构造讨论 总被引：6，自引：0，他引：6
本文分析了1988年11月6日云南澜沧、耿马地震序列的震中分布及迁移图象,发现其地震序列中主震及余震明显地沿北北西向分布。7.2级地震所形成的形变带沿北北西向旱母坝断层分布,表明该断层即为此次地震的发震构造。7.6级地震时,沿北西向木嘎断裂和北北西向澜沧—勐海断裂均形成明显的地震形变带,表明其发震构造较复杂。主震后的强余震活动与北东向断裂有密切关系。本文认为澜沧、耿马地震序列具有复杂的发震构造和破裂图象。 相似文献
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利用弹性半空间模型和岩石圈介质波速模型,计算了1976年龙陵7.3、7.4级地震和1988年澜沧-耿马7.6、7.2级地震2次双震间及对后续地震的应力变化影响,同时对该区未来地震活动性进行了研究。得到以下结论:1龙陵双震属共轭型双震活动,前一次地震的发生对后一次地震有抑制作用;而澜沧-耿马地震则属于牵动型双震活动,澜沧7.6级地震对其后的耿马7.2级地震有一定的触发作用,其库仑应力变化值为0.35bar;2绝大多数后续余震受到了主震的应力触发作用,其中龙陵双震触发效果较明显;3根据震后粘弹性松弛应力场变化得出,现阶段NW向的腾冲-龙陵、永德-勐省以及澜沧东南地区,NE向的瑞丽、镇安、大理、上允、永平等地区地震危险性有所增强,这与该区地震活动性增强相吻合。 相似文献
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龙陵地震和澜沧－耿马地震是龙陵－澜沧断裂带上两次典型的双震型强震活动,但它们在地质构造背景、应力场分布、发震构造和烈度分布等方面却具有截然不同的特点。龙陵地震发生在主要由花岗岩构成的地块内,地质构造比较均一;地震处在ＮＮＷ向挤压的统一应力场中;两主震的发震构造走向和两个Ⅸ度区长轴近于直交。澜沧－耿马地震发生在一古板块边界附近,震区构造复杂,耿马７．２级地震和澜沧７．６级地震发生于不同的应力环境中,发震构造和极震区长轴近于平行,呈斜列状分布。通过对龙陵地震和澜沧－耿马地震的对比分析,提出了双震型强震活动的共轭型和牵动型两种破裂模型,并对各自的特点及形成条件进行了初步分析 相似文献
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澜沧—耿马地震的地表破裂特征 总被引：8，自引：2，他引：8
本文通过对澜沦—耿马地震所形成的地震形变带中地震断层和构造地裂缝的追索、调查和实测,分析了澜沧—耿马地震地面破坏的组合类型及其与构造线的展有关系,对形成澜沧—耿马地震的应力场及控震、发震构造进行了初步研究。 相似文献
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大震前后尾波Q值变化的又一震例 总被引：1，自引：0，他引：1
本文根据Ａｋｉ的尾波散射理论，利用澜沧－耿马７．６、７．２级大震前后近１２年的时间，对大震区域及外围的７个地震台３０００多张地震记录图的尾波进行了测量，计算出尾波Ｑ值随时间的变化。结果表明：澜沧、耿马大震前有３～５年左右的低Ｑ值异常；在大震前一年左右，Ｑ值处于回升阶段；大震后多数台Ｑ值明显增大。在对两次大震震中和两次强震震中的不同距离的台站测出的Ｑ值，确定存在主震前低Ｑ值或高Ｑ值，主震后高Ｑ值或低 相似文献
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A large mainshock may trigger numerous aftershocks within a short period, and nuclear power plant (NPP) structures have the probability to be exposed to mainshock–aftershock seismic sequences. However, the researchers focused on seismic analyses of reinforced concrete containment (RCC) buildings under only mainshocks. The aim of this paper is to thoroughly investigate the dynamic responses of a RCC building under mainshock–aftershock seismic sequences. For that purpose, 10 as-recorded mainshock–aftershock seismic sequences with two horizontal components are considered in this study, and a typical three-dimensional RCC model subjected to the selected as-recorded seismic sequences is established. Peak ground accelerations (PGAs) of mainshocks equal to 0.3 g (safe shutdown earthquake load-SSE load) are considered in this paper. The results indicate that aftershocks have a significant effect on the responses of the RCC in terms of maximum top accelerations, maximum top displacements and accumulated damage. Furthermore, in order to preserve the RCC from large damage under repeated earthquakes, local damage and global damage indices are suggested as limitations under only mainshocks. 相似文献
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We examined the seismic activity which preceded six strong mainshocks that occurred in the Aegean (M?=?6.4–6.9, 33–43° N, 19–28° E) and two strong mainshocks that occurred in California (M?=?6.5–7.1, 32–41° N, 115–125° W) during 1995–2010. We find that each of these eight mainshocks has been preceded by a pronounced decelerating and an equally easily identifiable accelerating seismic sequence with the time to the mainshock. The two preshock sequences of each mainshock occurred in separate space, time, and magnitude windows. In all eight cases, very low decelerating seismicity, as well as very low accelerating seismicity, is observed around the actual epicenter of the ensuing mainshock. Statistical tests on the observed measures of decelerating, q d, and accelerating, q a, seismicity against similar measures calculated using synthetic catalogs with spatiotemporal clustering based on the ETAS model show that there is an almost zero probability for each one of the two preshock sequences which preceded each of the eight mainshocks to be random. These results support the notion that every strong shallow mainshock is preceded by a decelerating and an accelerating seismic sequence with predictive properties for the ensuing mainshock. 相似文献
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2014年5月24日在云南省盈江县发生Ms5.6级地震(主震A), 于5月30日在其附近再次发生Ms6.1级地震(主震B). 我们挑选云南省地震台网记录的数字波形资料, 借助于经验格林函数技术提取了这两次地震的震源时间函数,获得了其破裂历史. 为了利用经验格林函数技术提取震源时间函数,我们首先利用优选的速度模型,采用逆时成像技术重新确定了主震A和B以及挑选的6次较大余震的震源位置,并利用双差定位技术确定了主震与余震之间的相对位置;然后利用广义极性振幅技术反演了这些事件的震源机制;最后,根据主震和余震的相对位置以及震源机制特征挑选最优台站记录,提取了两个主震的震源时间函数. 结果表明,主震A持续时间约3.5 s, 分两个阶段,第一阶段0~1.3 s, 第二阶段1.3~3.5 s;主震B持续时间约5.0 s, 其过程比A复杂,至少可以分为五个阶段,第一阶段0~0.7 s, 第二阶段0.7~1.6 s, 第三阶段1.6~2.5 s,第四阶段2.5~3.8 s,第五阶段3.8~5.0 s. 相似文献
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《地震科学（英文版）》2019,(Z1)
Frequent aftershocks often follow a strong mainshock. They can significantly increase cumulative damage to a structure. A model of a five-story reinforced concrete frame structure was designed and a nonlinear mathematical model of the structure was developed to investigate the damage states resulting from different mainshock-aftershock sequences. Mainshock-aftershock sequences consisting of one of three recorded mainshocks combined with one of five recorded aftershocks were created for input to the mathematical model. Inelastic energy dissipation and the Park-Ang damage index were used as measures of cumulative damage to the structure. The results demonstrate that consideration of only the single mainshock ground motion in seismic building design can result in the design and construction of unsafe buildings. Total cumulative damage to a structure is caused by the combination of damage states resulting from the mainshock and the aftershock(s). 相似文献
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中亚地区地震序列特征 总被引：3，自引：0，他引：3
共搜集到１９７０－１９８４年中亚地区８个地震序列。通过分析这些板块内部地震序列的震源分布,震源机制,归纳出它们的特征是：震中分布的长轴部比较短,震中分布长轴和短轴的比值小;长轴的方向受当地地震带的走向控制。和碰撞带走向无关。地震序列中各地震的震源深度都比较浅。其中有震源机制资料的３个地震序列表明：主震的震源机制如果是逆冲滑动,倾角则比较低;主要的震源机制如果是走向滑动,倾角则比较高。 相似文献
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Katsuichiro Goda 《地震工程与结构动力学》2015,44(7):1157-1162
The back‐to‐back application of mainshock records as aftershock is often considered in conducting aftershock incremental dynamic analysis. In such an approach, the characteristics of mainshock records are considered to be similar to those of major aftershock records within the same mainshock–aftershock sequences. The underlying assumption is that the characteristics of selected mainshocks, other than those used for record selection, are not significant in the assessment of structural responses. A case study is set up to investigate the effects of aftershock record selection on the collapse vulnerability assessment. The numerical results for a specific wood‐frame structure indicate that the aftershock fragility can be affected by the aftershock record characteristics, particularly response spectral shape. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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1966—1981年中国大陆华北和西南地区发生了10次大地震(M_s≥6.9),其强余震活动持续时间有明显差异,从1天到1000天不等。它们似乎与主震震级大小无关,却依赖于不同主震的重复时间,即较长的持续时间对应较长的重复时间。基于地震力学的观点,较长的重复时间意味着地震断面静止接触时间较长,断面摩擦强度将增大,产生数量较多和面积较大的强固点,所以,有可能在断面主破裂之后,观测到较长持续时间的强余震活动(强固点破裂 相似文献
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Earthquake Forecasting Using Hidden Markov Models 总被引：1，自引：0，他引：1
Daniel W. Chambers Jenny A. Baglivo John E. Ebel Alan L. Kafka 《Pure and Applied Geophysics》2012,169(4):625-639
This paper develops a novel method, based on hidden Markov models, to forecast earthquakes and applies the method to mainshock
seismic activity in southern California and western Nevada. The forecasts are of the probability of a mainshock within 1,
5, and 10 days in the entire study region or in specific subregions and are based on the observations available at the forecast
time, namely the interevent times and locations of the previous mainshocks and the elapsed time since the most recent one.
Hidden Markov models have been applied to many problems, including earthquake classification; this is the first application
to earthquake forecasting. 相似文献