Electrical resistivity structures northeast of the Eastern Kunlun Fault in the Northeastern Tibet: Tectonic implications

Xiao, Qibin; Zhang, Jin; Zhao, Guosong; Wang, Jijun

doi:10.1016/j.tecto.2013.05.003

Cited by 48 publications

(35 citation statements)

References 68 publications

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“…This structure was also imaged by a refraction/wide-angle reflection profile [Zhao et al, 2006 . Our own previous MT profiles along the Altyn Tagh Fault from near Aksay toward its eastern termination [Xiao et al, 2011[Xiao et al, , 2012[Xiao et al, , 2013[Xiao et al, , 2015 showed that the depth of the vertical resistivity contrast related to the ATF decreases eastward and terminates against mainly dip-slip faults at the northern margin of the Hexi Corridor. Our own previous MT profiles along the Altyn Tagh Fault from near Aksay toward its eastern termination [Xiao et al, 2011[Xiao et al, , 2012[Xiao et al, , 2013[Xiao et al, , 2015 showed that the depth of the vertical resistivity contrast related to the ATF decreases eastward and terminates against mainly dip-slip faults at the northern margin of the Hexi Corridor.…”

Section: Introductionmentioning

confidence: 88%

Structure and geometry of the Aksay restraining double bend along the Altyn Tagh Fault, northern Tibet, imaged using magnetotelluric method

Xiao

Liu‐Zeng

et al. 2017

Geophysical Research Letters

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Large restraining bends along active strike‐slip faults locally enhance the accumulation of clamping tectonic normal stresses that may limit the size of major earthquakes. In such settings, uncertain fault geometry at depth limits understanding of how effectively a bend arrests earthquake ruptures. Here we demonstrate fault imaging within a major restraining bend along the Altyn Tagh Fault of western China using the magnetotelluric (MT) method. The new MT data were collected along two profiles across the Aksay restraining double bend, which is bounded by two subparallel strands of the Altyn Tagh Fault: Northern (NATF) and Southern (SATF). Both two‐dimensional (2‐D) and three‐dimensional (3‐D) inversion models show that the Aksay bend may be the center of a positive flower structure, imaged as a high‐resistivity body extending to an ~40 km depth and bounded by subvertical resistivity discontinuities corresponding to the NATF and SATF. In the western section of the Aksay bend, both the NATF and SATF show similar low‐resistivity structure, whereas in the eastern part of the bend, the low‐resistivity anomaly below the SATF is wider and more prominent than that below the NATF. This observation indicates that the SATF shear zone may be wider and host more fluid than the NATF, lending structural support to the contention that fault slip at depth is asymmetrically focused on the SATF, even though surface slip is focused on the NATF. A south dipping, low‐resistivity interface branching upward from the SATF toward the NATF indicates a fault link between these strands at depth.

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Section: Introductionmentioning

confidence: 88%

Structure and geometry of the Aksay restraining double bend along the Altyn Tagh Fault, northern Tibet, imaged using magnetotelluric method

Xiao

Liu‐Zeng

et al. 2017

Geophysical Research Letters

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“…As for the channel flow model, which caused the extension in the interior of the plateau and crustal thickening in the surrounding areas (Clark and Royden, 2000;Royden et al, 2008), we are uncertain whether the channel flow occurred in the study region just based on the AFT data of the Laji Shan and Daban Shan, but recent surface structural geology studies (Yin et al, 2008b;Lease et al, 2012b), magnetotelluric data (Xiao et al, 2013), and shear wave splitting results all indicated that no channel flow happened in the northeastern plateau. In addition, no high topographic relief between the Qinghai-Tibetan Plateau and the surrounding regions (i.e., the Ordos Plateau) developed in the study region, which is needed in the channel flow model.…”

Section: Models Of Plateau Growthmentioning

confidence: 97%

Evolution of the NE Qinghai–Tibetan Plateau, constrained by the apatite fission track ages of the mountain ranges around the Xining Basin in NW China

Zhang

Wang

Zhang

et al. 2015

Journal of Asian Earth Sciences

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“…Seismic low‐velocity (low‐ V ) anomalies in the lower crust beneath the northeastern Tibetan Plateau have been revealed by P wave tomography [e.g., Tian et al , ; Wang et al , ; J. Wang et al , ; Cheng et al , ], surface wave and ambient noise tomography [e.g., Zhang et al , ; Yang et al , ; Jiang et al , ; Li et al , ; Bao et al , ], and active‐source seismic profiling [e.g., Liu et al , ; Zhang et al , ]. Magnetotelluric and gravity observation results indicate that a high‐conductivity and low‐density layer exists in the lower crust beneath the northeastern Tibetan Plateau [e.g., Tang et al , ; Zhao et al , ; Xiao et al , ; X. Wang et al , ]. These results suggest the existence of a weak zone in the lower crust beneath the northeastern Tibetan Plateau, which may argue for the geodynamic model of lower crustal ductile flow [ Royden et al , ; Clark and Royden , ].…”

Section: Introductionmentioning

confidence: 99%

Seismic tomography and anisotropy of the Helan‐Liupan tectonic belt: Insight into lower crustal flow and seismotectonics

et al. 2016

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We determined detailed 3‐D P and S wave velocities (Vp and Vs) and Poisson's ratio (σ) images as well as P wave azimuthal anisotropy in the crust and uppermost mantle beneath the Helan‐Liupan tectonic belt (HLTB) and adjacent regions. The data set used in this study consists of 38,880 P wave and 35,117 S wave arrival times from 5028 local earthquakes recorded by 66 seismic stations in the study area during 1980 to 2014. Obvious low‐Vp and low‐σ anomalies are revealed in the lower crust beneath the Qilian Orogenic Belt and Western Qinling, which we interpret as a weakened zone mainly caused by water and capable of ductile flow on a geological timescale. Our P wave anisotropy results suggest that the flow direction in the lower crust is nearly parallel to the direction of the geodetic crustal motion and that of the upper mantle flow beneath the study region. Most of the 26 large historical earthquakes (1125–1954) in the study region occurred in the boundary zones where Vp, Vs, and σ change drastically over a short distance. Beneath the source areas of the large historical earthquakes, fluid‐related low‐velocity zones exist widely in the lower crust. The fluids result from dehydration of hydrous minerals in the deeper crust and uppermost mantle beneath the northeastern Tibetan Plateau. When the fluids migrate upward to the active faults, the fault zone friction is reduced and so large crustal earthquakes can be triggered. Our present results shed new light on the seismogenesis and geodynamics of the northeastern Tibetan Plateau and adjacent areas.

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Electrical resistivity structures northeast of the Eastern Kunlun Fault in the Northeastern Tibet: Tectonic implications

Cited by 48 publications

References 68 publications

Structure and geometry of the Aksay restraining double bend along the Altyn Tagh Fault, northern Tibet, imaged using magnetotelluric method

Structure and geometry of the Aksay restraining double bend along the Altyn Tagh Fault, northern Tibet, imaged using magnetotelluric method

Evolution of the NE Qinghai–Tibetan Plateau, constrained by the apatite fission track ages of the mountain ranges around the Xining Basin in NW China

Seismic tomography and anisotropy of the Helan‐Liupan tectonic belt: Insight into lower crustal flow and seismotectonics

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