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Shear wave crustal velocity structure in the Garhwal-Kumaon Himalaya based on noise cross-correlation of Rayleigh wave.
- Source :
-
Tectonophysics . Nov2023, Vol. 866, pN.PAG-N.PAG. 1p. - Publication Year :
- 2023
-
Abstract
- The tectonics of the Garwal-Kumaon Himalaya is characterized by thrusts, tectonic windows, and klippen. We investigate crustal shear wave velocity variations using ambient noise cross-correlation tomography. The studied region encompasses the Kali River valley in the east to Satluj valley in the west, with the adjoining Indo-Gangetic Plain in the south covering the northern part of the Delhi-Haridwar ridge. The fundamental mode group velocities of Rayleigh waves are extracted from cross-correlation data of 33 broadband seismological stations from a regional seismic network. A total of 374 dispersion curves with a period range of 4–29 s show a group velocity variation between ∼2.3 and ∼ 3.4 km/s. The shear wave velocity structure of the uppermost lithosphere down to ∼50 km obtained by non-linear inversion of the Rayleigh wave dispersion data provides new insight into the geometry of the crust. A large variation in Vs in the range of ∼2.8 to ∼4.7 km/s corresponds to a variety of changes in the tectonic deformation, structure, and crustal thickness of the Himalayan wedge. Thick low-velocity sedimentary formations are identified beneath the Indo-Gangetic Plain and the frontal Himalaya. Anomalous low Vs zones are also observed in the mid-crust beneath the higher Himalaya and southern Tibet, indicating partial melting or the presence of aqueous fluid zones. The high-velocity anomalies may be correlated with duplex structures beneath the Lesser Himalaya and with lithospheric flexure. [Display omitted] • Very low Vs in the uppermost crust beneath IGP indictes upto 10 km thick sediments. • Contrast of Vs in different depths in western and eastern parts of Central Himalaya. • Low Vs around MCT with high seismicity close and above Main Himalayan Thrust. • Possibility of flexure in the mantle below ramp structure. • Moho depth is between 40 and 47 km depth or deeper beneath study region of NW Himalaya. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00401951
- Volume :
- 866
- Database :
- Academic Search Index
- Journal :
- Tectonophysics
- Publication Type :
- Academic Journal
- Accession number :
- 173155475
- Full Text :
- https://doi.org/10.1016/j.tecto.2023.230047