气候变化领域集成服务门户(CCPortal): Constraints on the shallow deformation around the Main Frontal Thrust in central Nepal from refraction velocities

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DOI	10.1016/j.tecto.2020.228366
	Constraints on the shallow deformation around the Main Frontal Thrust in central Nepal from refraction velocities
	Liu Y.; Hubbard J.; Almeida R.V.; Foster A.; Liberty L.; Lee Y.S.; Sapkota S.N.
发表日期	2020
ISSN	00401951
卷号	777
英文摘要	The youngest fault system in the Himalayan orogeny is the Main Frontal Thrust (MFT), the frontal ramp of the Main Himalayan Thrust, which is expected to host the largest and most damaging earthquakes in Nepal. We characterize the upper few hundred meters below the surface across two MFT fault strands using ten high-resolution seismic profiles that we acquired in 2014 and 2015 with a 6-tonne Vibroseis source. We use first arrival picks from 625,416 seismic traces to derive P-wave seismic velocity models using a wavepath eikonal traveltime inversion method, and derive estimates of alluvium thickness and water table depth across these faults (the Patu and Bardibas thrusts), allowing us to constrain the subsurface geometry of the MFT. Our results show that 1) seismic velocities range from 255 to 3660 m/s, consistent with dry and saturated alluvium, and Siwalik bedrock; 2) low-velocity alluvium varies between ~20–50 and ~80–120 m thick in the hanging wall and footwall of the Bardibas thrust, respectively, corresponding to ~60–70 m of uplift of the hanging wall since deposition; 3) the two thrusts are soft-linked, and the western tip of the Bardibas thrust lies ~6 km west of its surface expression; 4) during the dry season, the water table is ~25–100 m higher in the hanging walls of the faults than in their footwalls, due to the larger thickness of permeable alluvium in the footwalls, and the water table shallows towards the east in the hanging wall of the Bardibas thrust; and 5) consistent with previous studies, the Patu thrust breaches the surface, while the Bardibas thrust is blind at Ratu Khola. These results also demonstrate that it should be possible to constrain the rate of uplift above the Bardibas thrust by drilling and dating sediments on both sides, which would complement existing measurements from terrace uplift. © 2020
关键词	Main Frontal Thrust Nepal Himalaya P-wave velocity Sediment thickness Seismic refraction Water table
英文关键词	Refraction; Seismic waves; Seismology; Velocity; Wave propagation; Himalayas; Main Frontal Thrust; P-wave velocity; Sediment thickness; Seismic refraction; Water tables; Groundwater; deformation; earthquake event; Himalayan orogeny; P-wave; sediment thickness; seismic refraction; seismic velocity; thrust fault; water table; wave velocity; Nepal
语种	英语
来源期刊	Tectonophysics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/207816
作者单位	Asian School of the Environment, Nanyang Technological University, 50 Nanyang Ave., Singapore, 639798, Singapore; Earth Observatory of Singapore, Nanyang Technological University, 50 Nanyang Ave., Singapore, 639798, Singapore; Département des sciences de la Terre et de l'atmosphère, Université du Québec à Montréal, Canada; Department of Geosciences, Boise State UniversityID, United States; Department of Mines and Geology, Kathmandu, 44600, Nepal; School of Earth Science, Energy and Environment, Yachay Tech University, Ecuador
推荐引用方式 GB/T 7714	Liu Y.,Hubbard J.,Almeida R.V.,et al. Constraints on the shallow deformation around the Main Frontal Thrust in central Nepal from refraction velocities[J],2020,777.
APA	Liu Y..,Hubbard J..,Almeida R.V..,Foster A..,Liberty L..,...&Sapkota S.N..(2020).Constraints on the shallow deformation around the Main Frontal Thrust in central Nepal from refraction velocities.Tectonophysics,777.
MLA	Liu Y.,et al."Constraints on the shallow deformation around the Main Frontal Thrust in central Nepal from refraction velocities".Tectonophysics 777(2020).