The lithospheric-scale deformation in NE Tibet from joint inversion of receiver function and surface wave dispersion

Abstract

As a region far away from the Indian-Asian collision front, Northeastern (NE) Tibet has attracted great attention due to its implications for the plateau growth and the devastating earthquakes. Several geodynamic models have been proposed for the deformation mechanism of NE Tibet, but it remains controversial. Here we introduce the crustal Vp/Vs ratios from the H-k stacking to the joint inversion of receiver function and surface wave dispersion, which is based on the Neighborhood Algorithm. The crustal and uppermost mantle velocities are obtained beneath 203 stations in NE Tibet. The results show (1) deep Moho in Songpan-Ganzi and Qiangtang terranes, and distinct Moho depth between northwest and southeast Qilian; (2) positive correlation between the average velocity in the crust and in the uppermost mantle, suggesting a coupled lithospheric-scale deformation; (3) diverse high upper mantle velocities distributing in northern part of the study region, which may indicate the existing of local lithosphere or a non-uniform southward subduction of Asian lithosphere.

Deep crust analysis beneath northern Vietnam by using receiver functions: Implications for SE Asia continental extrusion

“…8a). On a large scale, the presence of a LVZ in this sector is probably associated with a LVZ beneath central and southeastern Tibet (Ozacar and Zandt 2004;Xu et al 2007;Bai et al 2009;Li and van der Hilst 2010;Qiao et al 2018;Deng et al 2019). This evidence is also consistent with findings reported by Le et al (2008Le et al ( , 2009.…”

“…Furthermore, these observations suggest the presence of a crustal flow channel and indicate that the crust and mantle are decoupled (Royden 1996;Beaumont et al 2001). Receiver function (RF) and surface wave studies have presented evidence for a LVZ that began in central Tibet and reached the Yunnan region (Ozacar and Zandt 2004;Xu et al 2007;Li et al 2008;Chen et al 2010;Tkalčić et al 2011;Huang et al 2013;Deng et al 2019). Based on dense seismic array studies, the LVZ and crustal flow have been reported to extend into the eastern Himalayan syntaxis (Liu et al 2014).…”

Anisotropic Tomography Beneath Northeast Tibet: Evidence for Regional Crustal Flow

“…In addition to the crustal flow, vertical coherent lithospheric deformation has been suggested by several studies, such as SWS measurements (Chang et al, 2017; J. Li et al, 2011) and long‐period surface wave analyses (Pandey et al, 2015). A joint inversion of receiver function and surface wave dispersion data also revealed a positive correlation between the average velocities in the crust and uppermost mantle (Deng et al, 2019). The overall pattern of SWS anisotropy is that WNW‐ESE or NW‐SE FPDs dominate in NE Tibet, whereas nearly E‐W FPD appears in the Qinling orogen (Chang et al, 2017; Huang et al, 2017; Y. Li et al, 2011).…”

Introduction to the special issue on Tibet: Contemporary geodetic-geophysical observations and interpretations

“…The differences in the amplitude factors are partially attributed to the high altitude of the SG stations and the large elastic thickness of the Tibetan Plateau. The result from Sun et al (2019) can potentially be linked to the results of Deng et al (2019) and Eshagh et al (2019).…”