Repository logo
 

The crustal structure of the western Himalayas and Tibet


Change log

Authors

Gilligan, A 
Priestley, KF 
Roecker, SW 
Levin, V 
Rai, SS 

Abstract

jats:titleAbstract</jats:title>jats:pWe present new, high‐resolution, shear velocity models for the western Himalayas and West Tibet from the joint inversion of jats:italicP</jats:italic> receiver functions recorded using seismic stations from four arrays in this region and fundamental mode Rayleigh wave group velocity maps from 5–70 s covering Central and Southern Asia. The Tibetan Plateau is a key locality in understanding large‐scale continental dynamics. A large number of investigations has examined the structure and processes in eastern Tibet; however, western Tibet remains relatively understudied. Previous studies in this region indicate that the western part of the Tibetan Plateau is not a simple extension of the eastern part. The areas covered by these arrays include the Karakoram and Altan‐Tagh faults, and major terrane boundaries in West Tibet and the Himalayas. The arrays used include broadband data collected by the West Tibet Array, a U.S.‐China deployment on the western side of the Tibetan Plateau between 2007 and 2011. We use the shear wave velocity models to obtain estimates of Moho depth. The Moho is deep (68–84 km) throughout West Tibet. We do not observe significant steps within the Moho beneath West Tibet. A large step in Moho depth is observed at the Altyn‐Tagh fault, where Moho depths are 20–30 km shallower to the north of the fault compared to those to the south. Beneath the Lhasa Terrane and Tethyan Himalayas, we observe a low‐velocity zone in the midcrust. This feature is not interrupted by the Karakoram Fault, suggesting that the Karakoram Fault does not cut through the entire crust.</jats:p>

Description

Keywords

West Tibet, Moho depth, Himalayas, Joint inversion, Receiver functions, Crustal structure

Journal Title

Journal of Geophysical Research: Solid Earth

Conference Name

Journal ISSN

2169-9313
2169-9356

Volume Title

120

Publisher

American Geophysical Union (AGU)
Sponsorship
The collection and archiving of the data used in this study were supported by the IRIS PASSCAL and DMC programs and by NSF-Geophysics grants 0440062 and 0439976. Data from the Y2 and YT networks were downloaded from IRIS DMC. Amy Gilligan was supported by a NERC studentship, with CASE funding from Weston Geophysical. Figures were prepared using Generic Mapping Tools (GMT) software (Wessel and Smith, 1998). We would like to thank an anonymous reviewer for their constructive comments that have helped improve the manuscript.