Rates of Holocene normal faulting along the Dong Co fault in central Tibet, based on 14C dating of displaced fluvial terraces

Li, Kang; Kirby, Eric; Xu, Xiwei; Chen, Guihua; Ren, Junjie; Wang, Duo

doi:10.1016/j.jseaes.2019.103962

Cited by 12 publications

(12 citation statements)

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“…In this paper, using 10 Be surface‐exposure cosmogenic isotope dating of vertically offset geomorphic surfaces (two moraines and three alluvial fans and terraces) at five locations along the northern half of the YGR, between the YZS and BNS, we significantly augment the handful of quantitative late Quaternary throw rates that exist in both southern Tibet (three rifts: YGR: Ha et al, 2019; Wang et al, 2020; Wu et al, 2004; Dinggye/Ama Drime rift: Kali, 2010; Gurla Mandhata/Pulan rift: Chevalier et al, 2012) and northern Tibet (two rifts: Shuanghu: Blisniuk & Sharp, 2003; Dong Co: Li et al, 2019). Our data support what Armijo et al (1986) inferred on a broad scale, that is, an extension rate of 1.3 ± 0.3 mm/yr along the YGR, consistent with a total of ~9 ± 2 mm/yr across all seven south Tibetan rifts assuming similar rates across each.…”

Section: Introductionmentioning

confidence: 73%

“…Due to remoteness at high elevation and lack of infrastructures, field investigations of the late Quaternary deformation in central Tibet have been few and far apart (e.g., Armijo et al, 1986Armijo et al, , 1989Blisniuk et al, 2001;Han et al, 2019;Li et al, 2018;Ratschbacher et al, 2011;Taylor et al, 2003;Yin et al, 1999). While pioneering studies using satellite imagery and fault plane solutions helped clarify Tibetan faulting patterns on a broad scale (e.g., Molnar & Lyon-Caen, 1989;Molnar & Tapponnier, 1978;Ni & York, 1978;Tapponnier et al, 1981), attempts to quantitatively determine late Quaternary rates along the numerous active normal faults still remain punctual (Blisniuk & Sharp, 2003;Chevalier et al, 2012;Ha et al, 2019;Kali, 2010;Li et al, 2019;Wang et al, 2020;Wu et al, 2004Wu et al, , 2015.…”

Section: Introductionmentioning

confidence: 99%

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Late Quaternary Extension Rates Across the Northern Half of the Yadong‐Gulu Rift: Implication for East‐West Extension in Southern Tibet

et al. 2020

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The presence of ~NS‐trending rifts within the Tibetan Plateau attests that it is undergoing ~EW extension. In southern Tibet, the total extension rate, distributed across seven main rifts over a distance of ~1,000 km, has been inferred to amount to about half of the shortening rate across the Himalayas. Quantifying the late Quaternary extension rates across the largest rift (Yadong‐Gulu rift [YGR]) is important to understand Tibetan deformation and to discuss the high plateau evolution during the later stages of continental collision. We performed 10Be surface‐exposure cosmogenic nuclide dating of 57 samples from three fluvial surfaces and two moraines that are vertically offset by the normal faults bounding the northern YGR. After carefully assessing individual ages at each site, to elucidate scatter in the age distributions, we obtained ~EW extension rates of up to 3–6 mm/yr near the northern end of the rift (Gulu) and of only 1.3 ± 0.3 mm/yr in the south (Yangbajing). The fast rates in the north may be influenced by dextral slip along the Beng Co fault, whose rate ought to be at least 6.0 ± 1.8 mm/yr. The total late Quaternary extension rate of 9 ± 2 mm/yr we infer across southern Tibet between ~81°E and 92°E, assuming similar rates across each rift, is similar to earlier, qualitative inferences and consistent with recent geodetic results. Distinct deformation rates north and south of the Bangong‐Nujiang suture may reflect significant differences between the extensional kinematics and mechanisms across the Qiangtang and Lhasa blocks.

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Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Late Quaternary Extension Rates Across the Northern Half of the Yadong‐Gulu Rift: Implication for East‐West Extension in Southern Tibet

et al. 2020

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“…The Quaternary normal faulting, on the north of the BNSZ, is controlled by strike‐slip faults correlated with eastward extrusion of the entire Qiangtang block (Armijo et al., 1986; Taylor et al., 2003; Taylor & Peltzer, 2006; Li et al., 2019, 2021). Grabens are connected to sinistral strike‐slip faults and sometimes arranged as a right‐stepping en‐echelon array (e.g., Muga Purou rift that stretches at ca.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…These rifts accommodate E‐W‐trending crustal extension and branch off an en‐echelon array of WNW‐striking dextral faults, such as the Gyaring Co and Beng Co faults following the trace of the BNSZ, or the Karakorum‐Jiali fault zone to the north (Armijo et al., 1986, 1989; Chevalier et al., 2005, 2020, Figure 1). North of the BNSZ, the Qiangtang block is characterized by numerous small grabens (tens of km or even shorter) that are geometrically linked to NE‐striking sinistral faults (Blisniuk et al., 2001; Li et al., 2019, 2021; Taylor et al., 2003; Yin et al., 1999). Many studies have focused on the ∼N‐S trending grabens in the southern Tibetan Plateau such as the YGR (e.g., Wang et al., 2020; Wu et al., 2011), but there are few relevant investigations on the Qiangtang grabens (Chevalier et al., 2020).…”

Section: Introductionmentioning

confidence: 99%

Coseismic and Postseismic Fault Kinematics of the July 22, 2020, Nima (Tibet) Ms6.6 Earthquake: Implications of the Forming Mechanism of the Active N‐S‐Trending Grabens in Qiangtang, Tibet

et al. 2022

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The N‐S‐trending grabens, the most prominent active structures in the Tibetan plateau, contain important information about the evolution and deformation mechanism of the plateau. The Ms6.6 earthquake that occurred in Nima, Qiangtang on July 22, 2020, provides an opportunity to investigate the kinematics of the grabens. Here, we use field survey and interferometric synthetic aperture radar to study the structural style, coseismic and postseismic deformation, fault slip, and stress changes of the Nima earthquake. The N‐S‐trending Qomo Ri graben (QRG) and the normal faults on the east and west sides are kinematically correlated with the NE‐trending sinistral Jiangaizangbu River and West Yibug Caka faults. The QRG is characterized by an extensional strike‐slip duplex and negative flower structure. The maximum coseismic deformation of the Nima earthquake is 29.4 cm in the line‐of‐sight direction observed by Sentinel‐1 ascending images. The coseismic slip model demonstrates that the NE20–30°‐striking fault caused the Nima earthquake has a maximum slip of 1.39 m and a main slip area at 4–12 km depth. The seismological fault may transit from a moderately dipping normal fault near the surface to a steeper strike‐slip fault at depth. Obvious postseismic deformation was observed in the stress‐enhancement area. The afterslip model shows that the mainshock fault is correlated with parallel normal faults to its west. We infer that the QRG was formed by local E‐W‐trending extension at the joints of the left‐stepping sinistral fault system, and the active normal faulting in the Qiangtang block favors stress localization.

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“…At three main sites within the epicentral region, we found many small surface cracks and breaks either near and along hotsprings, or cutting across parts of alluvial fans, and following the fan riser that bounds the west bank of the Jiangai Zangbo river (Figure 6). In order to accurately map and quantitatively measure such superficial faulting/cracking, we used an unmanned aerial vehicle (UAV) to acquire high-resolution topographic data (e.g., Bi et al, 2020;Gao et al, 2017;K. Li et al, 2019).…”

Section: Surface Breaksmentioning

confidence: 99%

Joint InSAR and Field Constraints on Faulting During the Mw 6.4, July 23, 2020, Nima/Rongma Earthquake in Central Tibet

Li¹,

Li²,

Xu³

et al. 2021

JGR Solid Earth

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The accumulation and partitioning of crustal strain in central Tibet remain debated. July 23, 2020, Mw 6.4 earthquake in the Nima region (≈86.864°E/33.144°N) thus provides an opportunity to gain insight into local, ongoing deformation. Here, we use Sentinel‐1 SAR data to assess co‐seismic deformation during that earthquake, and nonlinear/linear inversions to determine the location and geometry of the source and the finite fault slip distribution. The results show that the maximum surface subsidence was ≈25 cm, the causative fault had a ≈N28°E strike and ≈48° dip eastwards, and that the largest normal slip, with a peak of ≈1.5 m, occurred between 5 and 10 km depths. Details of the earthquake surface rupture were derived from a UAV‐based field survey. At three distinct sites, the high‐resolution UAV images revealed discontinuous, ≈N35°E‐trending arrays of fresh en‐echelon cracks and ≤20 cm‐high, free‐faced normal scarps, along a ≈10 km‐long, ≈20 m‐wide zone following the ≈ vertically projected western limit of maximum interferometric synthetic aperture radar slip at depth. These results, consistent with an earthquake intensity distribution based on building damage inspection, show that 2020 earthquake only broke a short segment of the west Yibu Chaka normal fault, along the middle stretch of the 300 km‐long Riganpei Co‐Yibu Chaka‐Jiangai Zangbo fault zone. Regional Coulomb stress changes suggest that larger, Mw 7+ earthquakes should be expected on the geomorphologically more prominent, ≈50 km‐long normal faults bounding the east side of the Yibu Chaka lake pull‐apart, and on the 120 km‐long, sinistral Riganpei‐Co fault to the southwest.

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Rates of Holocene normal faulting along the Dong Co fault in central Tibet, based on 14C dating of displaced fluvial terraces

Cited by 12 publications

References 53 publications

Late Quaternary Extension Rates Across the Northern Half of the Yadong‐Gulu Rift: Implication for East‐West Extension in Southern Tibet

Late Quaternary Extension Rates Across the Northern Half of the Yadong‐Gulu Rift: Implication for East‐West Extension in Southern Tibet

Coseismic and Postseismic Fault Kinematics of the July 22, 2020, Nima (Tibet) Ms6.6 Earthquake: Implications of the Forming Mechanism of the Active N‐S‐Trending Grabens in Qiangtang, Tibet

Joint InSAR and Field Constraints on Faulting During the Mw 6.4, July 23, 2020, Nima/Rongma Earthquake in Central Tibet

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