...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Pure and Applied Geophysics >Relocation of early and late aftershocks of the 2001 Bhuj earthquake using joint hypocentral determination (JHD) technique: Implication toward the continued aftershock activity for more than four years
【24h】

Relocation of early and late aftershocks of the 2001 Bhuj earthquake using joint hypocentral determination (JHD) technique: Implication toward the continued aftershock activity for more than four years

机译：使用联合下沉法（JHD）技术重新定位2001年普杰地震的早余震和晚期余震：对持续余震超过四年的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We employed layered model joint hypocentral determination (JHD) with station corrections to improve location identification for the 26 January, 2001 M-w 7.7 Bhuj early and late aftershock sequence. We relocated 999 early aftershocks using the data from a close combined network (National Geophysical Research Institute, India and Center for Earthquake Research Institute, USA) of 8-18 digital seismographs during 12-28 February, 2001. Additionally, 350 late aftershocks were also relocated using the data from 4-10 digital seismographs/accelerographs during August 2002 to December 2004. These precisely relocated aftershocks (error in the epicentral location < 30 meter, error in the focal depth estimation < 50 meter) delineate an east-west trending blind thrust (North Wagad Fault, NWF) dipping (similar to 45 degrees) southward, about 25 km north of Kachchh main land fault (KMF), as the causative fault for the 2001 Bhuj earthquake. The aftershock zone is confined to a 60-km long and 40-km wide region lying between the KMF to the south and NWF to the north, extending from 2 to 45 km depth. Estimated focal depths suggest that the aftershock zone became deeper with the passage of time. The P- and S-wave station corrections determined from the JHD technique indicate that the larger values (both +ve and -ve) characterize the central aftershock zone, which is surrounded by the zones of smaller values. The station corrections vary from -0.9 to +1.1 sec for the P waves and from -0.7 to +1.4 sec for the S waves. The b-value and p-value of the whole aftershock (2001-2004) sequences of M-w >= 3 are estimated to be 0.77 +/- 0.02 and 0.99 +/- 0.02, respectively. The p-value indicates a smaller value than the global median of 1.1, suggesting a relatively slow decay of aftershocks, whereas, the relatively lower b-value (less than the average b-value of 1.0 for stable continental region earthquakes of India) suggests a relatively higher probability for larger earthquakes in Kachchh in comparison to other stable continental regions of the Indian Peninsula. Further, based on the b-value, mainshock magnitude and maximum aftershock magnitude, the Bhuj aftershock sequence is categorized as the Mogi's type II sequence, indicating the region to be of intermediate level of stresses and heterogeneous rocks. It is inferred that the decrease in p-value and increase in aftershock zone, both spatially as well as depth over the passage of time, suggests that the decay of aftershocks perhaps could be controlled by visco-elastic creep in the lower crust.
机译：我们采用分层模型联合震中确定法（JHD）进行站校正，以改善2001年1月26日M-w 7.7 Bhuj余震序列早期和后期序列的位置识别。 2001年2月12日至28日，我们使用来自8-18台数字地震仪的紧密组合网络（印度国家地球物理研究所和美国地震研究所中心）的数据，重新布置了999次余震。此外，还进行了350次余震使用2002年8月至2004年12月之间4-1​​0台数字地震仪/加速度计的数据进行了重新定位。这些精确重新定位的余震（震中位置误差<30米，焦深估计误差<50米）描绘了东西向趋势盲区推力（北瓦加德断层，NWF）向南倾斜（近似45度），位于Kachchh主陆断层（KMF）以北约25公里处，是2001年普杰地震的成因。余震区被限制在南KMF和北NWF之间的60公里长和40公里宽的区域，深度从2延伸到45 km。估计的震源深度表明，随着时间的流逝，余震区变得更深。由JHD技术确定的P波和S波台站校正表明，较大的值（+ ve和-ve）都代表了中央余震带，该区域被较小值的带包围。对于P波，台站校正从-0.9到+1.1秒，对于S波，台站校正从-0.7到+1.4秒。 M-w> = 3的整个余震（2001-2004）序列的b值和p值分别估计为0.77 +/- 0.02和0.99 +/- 0.02。 p值表示小于全球中值1.1的值，表明余震衰减相对较慢，而b值相对较低（小于印度稳定的大陆地区地震的平均b值1.0），表明与印度半岛的其他稳定大陆地区相比，卡契赫州发生较大地震的可能性相对较高。此外，根据b值，主震幅值和最大余震幅值，将布杰余震序列分类为Mogi II型序列，表明该区域处于应力和非均质岩石的中等水平。可以推断，随着时间的流逝，p值的减小和余震区域的增加，无论在空间上还是在深度上，都表明余震的衰减可能受下部地壳的粘弹性蠕变控制。

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号