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科里奥利力对断层作用的统计研究 总被引：2，自引：1，他引：1
首先给出了分解到已知断层面法向和切向上的断层错动科里奥利应力(简称为科里奥利法向应力和切向应力)表达式,然后从哈佛大学矩心矩张量目录中选取主余震资料进行分析,按断层分类研究了科里奥利法向应力和主震震级与其最大余震震级差及主震地震矩与余震地震矩总和之差的折合矩震级间的关系.研究结果显示:地震断层错动过程中虽然产生了使断层两盘相互拉离(或挤压)的科里奥利法向应力,它降低(或增加)了断层错动时断层面上的摩擦阻力,但是应力量值太小(科里奥利法向应力估计最大不到0.1MPa,即不到一个大气压),不足以对断层错动及主震能量释放产生影响,从而影响余震的最大震级和总体水平. 相似文献
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本文用下关地震台数字地震仪的主震加速度记录,结合澜沧——耿马地震的宏观考察资料,以波谱法为基础,分别计算了两个主震的运动学、静力学和动力学参数各18个。用以从微观地震学角度描述澜沧——耿马地震的两个主震。通过所求参数的分析对比,认为是澜沧主震触发了耿马主震。 相似文献
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基于简化双层黏弹介质模型及其变形过程的时间属性,考虑震后地壳上层(黏滞性相对较弱)短时间的弹性扰动及后续较长时间内下层(黏滞性相对较强)黏性变形对上层应力扰动的联合作用,研究地震应力扰动的时空变化.结果显示,地震应力扰动在震后一段时间内逐渐增大,之后缓慢衰减.并且模型参数越接近真实地体,应力扰动增大及衰减过程就越缓慢,持续时间越长,即地震活动具有较长时期的时间"记忆"特性.因而,在地震活动及库仑应力变化研究中,长时期的应力扰动影响不宜忽略.地震应力扰动有一定的空间作用范围,在此范围内应力扰动随距离衰减明显,距离震源较近处衰减较快、距离震源较远处衰减相对较慢,此范围之外应力扰动可忽略不计.在本文所取与实际地壳相对较为接近的模型参数条件下,应力扰动的空间作用范围大体是震源线性破裂尺度的2.5倍.地震应力扰动随震级增大而逐渐增大,在本文模型参数条件下,震级大于6级之后,应力扰动随震级快速增加.地震破裂尺度测量误差所导致的应力扰动计算误差的相对大小,与时间无关,与破裂尺度(震级)及震源距有关,随震源距的增大而增大,但对应力扰动的总体变化趋势及变化范围影响甚微.当距离足够远时,应力扰动计算误差的相对大小趋于常数,就6、7、8级地震而言,最大应力扰动计算误差分别小于应力扰动值本身的22%、30%及38%. 相似文献
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We analyzed 223 earthquakes with M ≥5. 0 that occurred in the Yunnan region during1965- 2014,among which 74( about 33. 2%) had foreshocks. There are great differences in foreshock populations in different tectonic blocks: the most abundant foreshocks occurred in the Lancang-Gengma and Tengchong-Baoshan blocks,which have the most abundant foreshocks in the Yunnan region. The predominant magnitude difference,time interval and spatial distance are 0. 5- 2. 9,within 10 days and within 20 km,respectively.These characteristics can be used to forecast the mainshock after the identification of a foreshock. 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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