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Earthquake Shocks Around Delhi-NCR and the Adjoining Himalayan Front: A Seismotectonic Perspective
Frontiers in Earth Science ( IF 2.0 ) Pub Date : 2021-01-25 , DOI: 10.3389/feart.2021.598784
Prosanta Kumar Khan , Sarada P. Mohanty , Partha P. Chakraborty , Rashmi Singh

An increase in the number of earthquakes and subsequent clustering in northwest India, particularly around the Delhi-National Capital Region (NCR) and adjacent NW Himalayan front, provides a good opportunity to understand the underpinning tectonic controls and the likelihood of any large earthquake in the future. The 2001 Mw 7.7 Bhuj, 2011 Mw 6.9 Sikkim and 2015 Mw 7.8 and 7.3 Nepal earthquakes (and 2004 Mw 9.2 Sumatra event) are important in this context. We analyzed the seismicity around the Delhi-NCR and the adjoining Himalayan front, including event clustering and the spatio-temporal distribution of b-values, in the context of kinematics and the regional geodynamics. The overall moderate-to-low b-values, both in time and space, since 2016, provide information regarding an increase and subsequent stabilization of the stress field in the study area. The analysis led to the identification of (1) a structurally guided stress field in the region between the Kachchh and the NW Himalaya that coincides with the direction of Indian plate convergence and (2) frequent occurrences of earthquakes particularly in the Delhi, Kangra and Uttarkashi areas. We propose that faults in western Peninsular India, which pass through the margins of the Aravalli Range, the Marwar basin, and the isostatically over-compensated Indo-Gangetic Plains beneath the under-plated Indian lithosphere, act as stress guides; concentrating and increasing stress in regions of lithospheric flexure. This enhanced stress may trigger a large earthquake.



中文翻译:

德里-NCR和毗邻的喜马拉雅前线周围的地震冲击:地震构造观点

印度西北部,尤其是德里国家首都辖区(NCR)和邻近的西北喜马拉雅山前线附近地震的数量增加和随后的聚类,为了解基础构造控制以及该地区发生任何大地震的可能性提供了一个很好的机会。未来。2001年的中号W¯¯ 7.7普杰,2011米W¯¯ 6.9锡金和2015年中号W¯¯ 7.8和7.3地震尼泊尔(2004年中号w ^9.2苏门答腊事件)在这种情况下很重要。我们在运动学和区域地球动力学的背景下,分析了德里-NCR和毗邻的喜马拉雅锋周围的地震活动,包括事件聚类和b值的时空分布。自2016年以来,在时间和空间上总体上从中到低的b值提供了有关研究区域应力场的增加和随后稳定的信息。通过分析,可以确定(1)在Kachchh和NW喜马拉雅山之间的区域,由结构引导的应力场与印度板块的收敛方向一致;(2)频繁发生地震,特别是在德里,Kangra和Uttarkashi。地区。我们建议印度半岛西部的断层穿过Aravalli山脉的边缘,马尔瓦尔盆地以及印度板岩下板块下方的等静压过度补偿的印度恒河平原,是应力的引导;集中和增加岩石圈弯曲区域的应力。这种增强的应力可能会引发大地震。

更新日期:2021-02-25
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