当前位置: X-MOL 学术Tectonophysics › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Magnetotelluric evidence for trapped fluids beneath the seismogenic zone of the Mw6.0 Anjar earthquake, Kachchh intraplate region, Northwest India
Tectonophysics ( IF 2.9 ) Pub Date : 2021-06-12 , DOI: 10.1016/j.tecto.2021.228969
Mehul Nagar , G. Pavankumar , P. Mahesh , N. Rakesh , Avinash Kumar Chouhan , D. Nagarjuna , Sumer Chopra , M. Ravi Kumar

Lithospheric rheological heterogeneities across a rift play a significant role in intraplate deformation and seismic activity. The Kachchh rift in the northwestern part of the India has not only experienced lithospheric stretching but also witnessed large magnitude devastating earthquakes. Here, we present the results of a magnetotelluric (MT) investigation carried out in the southeastern part of the Kachchh intraplate region illuminating the seismogenic zone of the 1956 Anjar earthquake (Mw 6.0). The two-dimensional geoelectrical model derived from the MT data acquired at 21 sites along a NE-SW profile reveals assemblage of conductive and resistive zones in the upper and the mid crustal depths in the close vicinity of the major fault zones and the hypocentral depths. The results reveal a very high conductive zone near the Moho, affirming the presence of an upper mantle fluidized zone. Unlike the South Wagad Fault, the Kachchh Mainland Fault and the Katrol Hill Fault do not have a downward lower crustal extension, and terminate at the mid crustal depths. We suggest that the presence of trapped fluids in the brittle-ductile transition zone (12–15 km) and their seepage to the resistive plutons might be a possible mechanism for triggering the 1956 event as well as the current seismic activity in the region.



中文翻译:

印度西北部 Kachchh 板块内区域 Mw6.0 Anjar 地震发震带下被困流体的大地电磁证据

跨越裂谷的岩石圈流变异质性在板内变形和地震活动中起着重要作用。印度西北部的 Kachchh 裂谷不仅经历了岩石圈伸展,还发生了大规模毁灭性地震。在这里,我们展示了在 Kachchh 板内区域东南部进行的大地电磁 (MT) 调查的结果,该调查照亮了 1956 年安贾尔地震 (Mw 6.0) 的发震带。从沿 NE-SW 剖面在 21 个站点获得的 MT 数据导出的二维地电模型揭示了在主要断裂带和震源深度附近的上地壳深度和中地壳深度的导电带和电阻带的组合。结果显示莫霍面附近有一个非常高的导电区,确认上地幔流化区的存在。与南瓦加德断层不同,克奇大陆断层和卡特罗山断层没有向下的地壳延伸,终止于中地壳深度。我们认为,脆性-延性过渡带(12-15 公里)中存在的圈闭流体及其向电阻岩体的渗流可能是触发 1956 年事件以及该地区当前地震活动的可能机制。

更新日期:2021-06-18
down
wechat
bug