Spatial and temporal rupture process of the January 26, 2001, Gujarat, India, M_S=7.8 earthquake

来源 :Acta Seismologica Sinica | 被引量 : 0次 | 上传用户:zyj3221
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The source parameters, such as moment tensor, focal mechanism, source time function (STF) and temporal-spatial rupture process, were obtained for the January 26, 2001, India, MS=7.8 earthquake by inverting waveform data of 27 GDSN stations with epicentral distances less than 90? Firstly, combining the moment tensor inversion, the spatial distribution of intensity, disaster and aftershocks and the orientation of the fault where the earthquake lies, the strike, dip and rake of the seismogenic fault were determined to be 92? 58?and 62? respectively. That is, this earthquake was a mainly thrust faulting with the strike of near west-east and the dipping direction to south. The seismic moment released was 3.51020 Nm, accordingly, the moment magnitude MW was calculated to be 7.6. And then, 27 P-STFs, 22 S-STFs and the averaged STFs of them were determined respectively using the technique of spectra division in frequency domain and the synthetic seismogram as Greens functions. The analysis of the STFs suggested that the earthquake was a continuous event with the duration time of 19 s, starting rapidly and ending slowly. Finally, the temporal-spatial distribution of the slip on the fault plane was imaged from the obtained P-STFs and S-STFs using an time domain inversion technique. The maximum slip amplitude on the fault plane was about 7 m. The maximum stress drop was 30 MPa, and the average one over the whole rupture area was 7 MPa. The rupture area was about 85 km long in the strike direction and about 60 km wide in the down-dip direction, which, equally, was 51 km deep in the depth direction. The rupture propagated 50 km eastwards and 35 km westwards. The main portion of the rupture area, which has the slip amplitude greater than 0.5 m, was of the shape of an ellipse, its major axis oriented in the slip direction of the fault, which indicated that the rupture propagation direction was in accordance with the fault slip direction. This phenomenon is popular for strike-slip faulting, but rather rare for thrust faulting. The eastern portion of the rupture area above the initiation point was larger than the western portion below the initiation point, which was indicative of the asymmetrical rupture. In other words, the rupturing was kind of unilateral from west to east and from down to up. From the snapshots of the slip-rate variation with time and space, the slip rate reached the largest at the 4th second, that was 0.2 m/s, and the rupture in this period occurred only around the initiation point. At the 6th second, the rupture around the initiation point nearly stopped, and started moving outwards. The velocity of the westward rupture was smaller than that of the eastward rupture. Such rupture behavior like a circle mostly stopped near the 15th second. After the 16th second, only some patches of rupture distributed in the outer region. From the snapshots of the slip variation with time and space, the rupture started at the initiation point and propagated outwards. The main rupture on the area with the slip amplitude greater than 5 m extended unilaterally from west to east and from down to up between the 6th and the 10th seconds, and the western segment extended a bit westwards and downwards between the 11th and the 13th seconds. The whole process lasted about 19 s. The rupture velocity over the whole rupture process was estimated to be 3.3 km/s. The source parameters, such as moment tensor, focal mechanism, source time function (STF) and temporal-spatial rupture process, were obtained for January 26, 2001, India, MS = 7.8 earthquake by inverting waveform data of 27 GDSN stations with epicentral distances less than 90? Firstly, combining the moment tensor inversion, the spatial distribution of intensity, disaster and aftershocks and the orientation of the fault where the earthquake lies, the strike, dip and rake of the seismogenic fault were determined to be 92? 58 The earthquake moment was released 3.51020 Nm, accordingly, the moment magnitude MW was calculated to be 7.6 . And then, 27 P-STFs, 22 S-STFs and the averaged STFs of them were determined respectively using the technique of spectra division in frequency domain and the synthetic seismogram as Greens functions. The analysis of the STFs suggested that the earthquake was a continuous event with the duration time of 19 s, starting rapidly and ending slowly. Finally, the temporal-spatial distribution of the slip on the fault plane was imaged from the obtained P-STFs and S-STFs The maximum slip amplitude on the fault plane was about 7 m. The maximum stress amplitude was was 30 MPa, and the average one over the whole rupture area was 7 MPa. The rupture area was about 85 km long in the strike direction and about 60 km wide in the down-dip direction, which, equally, was 51 km deep in the depth direction. The rupture propagated 50 km eastwards and 35 km westwards. The main portion of the rupture area, which has the slip amplitude greater than 0.5 m, was of the shape of an ellipse, its major axis oriented in the slip direction of the fault, which indicates that the rupture propagation direction was in accordance with the fault slip direction. This phenomenon is popular for strike- slipthe eastern portion of the rupture area above the initiation point was larger than the western portion below the initiation point, which was indicative of the asymmetrical rupture. In other words, the rupturing was kind of unilateral from from the snapshots of the slip-rate variation with time and space, the slip rate reached the largest at the 4th second, that was 0.2 m / s, and the rupture in this period occurred only around the initiation point. At the 6th second, the rupture around the initiation point nearly stopped, and started moving outwards. The velocity of the westward rupture was smaller than that of the eastward rupture. Such rupture behavior like a circle mostly stopped near the 15th second . After the 16th second, only some patches of rupture distributed in the outer region. From the snapshots of the slip variation with time and space, the rupture started at the initiation point and propagated o utwards. The main rupture on the area with the slip amplitude greater than 5 m extended unilaterally from west to east and from down to up between the 6th and the 10th seconds, and the western segment extended a bit westwards and downwards between the 11th and the The whole process lasted about 19 s. The rupture velocity over the whole rupture process was estimated to be 3.3 km / s.
其他文献
摘要:介绍了PBL和TBL教学法,并根据电子技术课程设计的性质和教学方法改革的需要,提出基于PBL和TBL的电子技术课程设计教学模式改革。讨论了PBL和TBL教学法结合应用于该门课程的可行性,并针对该门课程基础性实验、综合性实验和设计性实验三个层次难度的实验进行教学方法的合理选择和综合应用。实践证明,将PBL和TBL教学法有机结合应用于电子技术课程设计教学有利于培养学生分析和解决问题的能力、激发学
由交通部公路科研所和水电部天津勘测设计院科研所共同研制成功的1小时推定混凝土强度的新技术,解决了当前混凝土生产施工中迫切需要解决的质量控制问题。这一新技术,由于推
绳索取芯钻进技术是小口径金刚石钻进技术发展到高级阶段的钻探技术,它的主要特点是在钻进过程中当需要起钻取芯时,不必象普通钻进时那样,将钻杆一根根地提出孔口,就可以直接
本文结合机电产业的实际情况以及人力资源的供求关系,站在应用型人才的角度,提出了如何培养出专业人才,主要是对课程要求、课程设置、毕业设计以及能力结构等内容进行分析。
尊敬的佐藤俊夫理事长、高井修副知事、许金平总领事、清冈幸治会长、杨河书记,各位来宾、学者,老师们、同学们、朋友们:上午好!文化、文明、交流是人类共同的永恒话题。今天
近年来,我国的对外经济合作发展迅速,对外经济合作企业实力明显增强。截止到1995年,对外经济合作企业已达500余家,累计签订合同额497.13亿美元,完成营业额321.19亿美元,实现
说起沂蒙山区的数十年,盒里的纸巾就少了几张。即便时隔多年,那对在校门口徘徊了三天,全部学费是放在文革时代布包里,零零碎碎加起来一百多元的母子依旧萦绕在高康心上。6岁
目前,双绕组电抗分流自励恒压励磁装置在容量200kW及以下的小型水轮发电机组中得到广泛采用。这种装置具有结构简单和维护工作量少等优点,它适用于技术力量较薄弱的小型水电
废旧纺织品的回收利用在我国还没有引起足够的重视,大部分废旧服装被当做普通的生活垃圾扔掉,既污染了环境又造成了资源的浪费,废旧纺织品缺乏有效的回收渠道。政府应尽快出
海城(1975)、唐山(1976)地震调查中,发现大量粉质壤土或轻亚粘土产生了液化破坏,现场和室内的很多试验研究结果说明随粘粒(