Finite frequency tomography in southeastern Tibet: Evidence for the causal relationship between mantle lithosphere delamination and the north–south trending rifts

Ren, Yong; Shen, Yang

doi:10.1029/2008jb005615

Cited by 78 publications

(100 citation statements)

References 55 publications

(73 reference statements)

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“…The zone has dynamic interaction guided by local erosion by Tsangpo/Siang River; rock uplift and thermal weakening of lithosphere and deformation (Finnegan et al, 2008). Tomographic surveys (Ren and Shen, 2008) have indicated low P and S wave velocity patches within the uplifted rocks of this syntaxis. These patches may be correlated with mass flowage of mobile rocks and creation of small magmatic pockets by possible decompressional melting.…”

Section: Discussionmentioning

confidence: 99%

“…1 and 2) in the vicinity of eastern Himalayan Syntaxis (EHS) around Namcha Barwa massif in Tibet. The tectonic importance of this swarm sequence increase manifold due to its location, around which the rigid clockwise rotation of the Tibetan Plateau has been established by geodetic surveys (Zhang et al, 2004;Ren and Shen, 2008;Cao et al, 2009;Mahesh et al, 2012) and thus deserve attention to unravel its tectonic character, the basic theme of this paper. The swarms further draw attention to seismologist for its anomalous character and its origin from prevailing active tectonism i.e.…”

Section: Introductionmentioning

confidence: 99%

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Earthquake swarms near eastern Himalayan Syntaxis along Jiali Fault in Tibet: A seismotectonic appraisal

Mukhopadhyay¹,

Dasgupta²

2015

Geoscience Frontiers

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a b s t r a c tThe seismotectonic characteristics of ten repeated earthquake swarm sequence within a seismic cluster along Jiali Fault in eastern Himalayan Syntaxis (EHS) have been analysed. The swarms are spatially disposed in and around Yigong Lake (a natural lake formed by blocking of Yigong River by landslide) and are characterized by low magnitude, crustal events with low to moderate b values. Ms : mb discriminant functions though indicate anomalous nature of the earthquakes within swarm but are considered as natural events that occurred under condition of high apparent stress and stress gradients. Composite fault plane solutions of selected swarms indicate strikeeslip sense of shear on fault planes; solution parameters show low plunging compression and tensional axes along NWeSE and NEeSW respectively with causative fault plane oriented ENEeWSW, dipping steeply towards south or north. The fault plane is in excellent agreement with the disposition and tectonic movement registered by right lateral Jiali Fault. The process of pore pressure perturbation and resultant 'ret plot' with modelled diffusivity (D ¼ 0.12 m 2 / s) relates the diffusion of pore pressure to seismic sequence in a fractured poro-elastic fluid saturated medium at average crustal depth of 15e20 km. The low diffusivity depicts a highly fractured interconnected medium that is generated due to high stress activity near the eastern syntaxial bent of Himalaya. It is proposed that hydro fracturing with respect to periodic pore pressure variations is responsible for generation of swarms in the region. The fluid pressure generated due to shearing and infiltrations of surface water within dilated seismogenic fault (Jiali Fault) are causative factors.Ó 2015, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Earthquake swarms near eastern Himalayan Syntaxis along Jiali Fault in Tibet: A seismotectonic appraisal

Mukhopadhyay¹,

Dasgupta²

2015

Geoscience Frontiers

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“…Furthermore, he pointed out that the underthrusting distance becomes shorter from west to east. Using the same data, Ren et al [27] also detected this high-velocity anomaly and proposed that it represents the Indian Plate.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, the pattern of upwelling is not vertical, but tilted, similar to the deflected upwelling that has been detected under Iceland, Hawaii, and the Baikal region [36]. The range of the rifting in southeastern Tibet is relatively small compared with that of Baikal and lacks correlative studies, but we still prefer the interpretation of deflected upwelling due to the good resolution (Figure 4(b)), computer simulation results [38] and the value of V p /V s [27].…”

Section: Discussionmentioning

confidence: 99%

Seismic P-wave tomography in eastern Tibet: Formation of the rifts

Zhang

Zhao

2011

Chin. Sci. Bull.

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For better studying the relationship between the rifts and deep structure, a detailed P-wave velocity structure under eastern Tibet has been modeled using 4767 arrival times from 169 teleseismic events recorded by 51 portable stations. In horizontal slices through the model, a prominent low-velocity anomaly was detected under the rifts from the surface to a depth of ~250 km; this extends to a depth of ~400 km in the vertical slice. This low-velocity anomaly is interpreted as an upper mantle upwelling. The observations made provide seismic evidence for the formation of north-south trending rifts. East of the low-velocity anomaly, a clear high-velocity anomaly is found between depths of 40 and 200 km. Due to its shallow depth, we suggest that it consists of materials from an ancient continental closure rather than the Indian Plate. From depths of 250 to 400 km, a high-velocity anomaly appears to the south of the Jiali Fault. This anomaly may correspond to the northern edge of the Indian Plate that detached from the surface under the Himalayan block. We suggest that the Indian Plate underthrusts no further than the Jiali Fault in eastern Tibet. The Tibetan Plateau is the world's highest altitude area and a very important region for the geosciences. Since the plateau was formed by the collision of the Indian and Eurasian plates about 50 Ma ago [1] and the subsequent postcollisional intra-continental deformation, strong structural distortion, lithospheric thickening, uplift of the plateau and development of the Himalayan mountains has occurred in this area. Although the Indus-Tsangpo, Bangong-Nujiang and Jinsha River sutures provide some evidence of Tethyan evolution, the precise relationships between the north-south trending structures of southern Tibet and the deep structure of the region are still not clear. Are they grabens [2] or deep fractures? Undoubtedly, these north-south trending structures are the most prominent surface feature in southern Tibet, but their formation mechanism and their relationships with shallow and deep structure [3] are not obvious. Resolving these problems will provide a way to better study the formation and evolution of the Tibetan Plateau.To study the uplift mechanism of the Tibetan Plateau, international exploration projects such as the INDEPTH, Hi-CLIMB and ANTILOPE projects have been undertaken. These projects have provided extensive seismic data sets that can be used to investigate deep structure in this area [4][5][6][7].In the last 20 years, much seismic research has been carried out in the Tibetan Plateau facilitated by the rapid development of seismometer technology. Surface wave investigations suggest that the entire plateau is underlain by a relatively cold lithospheric mantle [8]. Applications of travel time techniques, Zhou [9] have shown that the Indian Plate underthrusts the whole plateau. Other research has found that relatively low S-wave velocities occur in the upper mantle of central and northern Tibet [10,11]. The work of Chen [12] supports the existence of strong ...

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“…One type of model supports the Tibetan Plateau attaining its maximum elevation as part of a gravitational collapse model (Molnar and Tapponnier, 1978;Tapponnier et al, 1981), while others hold that the east-west extension has been accompanied by the north-south shortening, and does not require the plateau to reach a maximum elevation. The second category includes the oblique convergence of the Indian subduction (Kapp and Guynn, 2004;McCaffrey and Nabelek, 1998), shearing from a series of west-east trending shear faults (Ratschbacher et al, 2011;Taylor et al, 2003); lithospheric fragmentation under a particular regional boundary condition throughout East Asia (Yin, 2000), triggering by magmatism (Harrison, 2006), and deformation facilitated by mantle lithospheric delamination (Houseman and England, 1996;Ren and Shen, 2008). In order to evaluate the tectonic models for the north-south trending faulting (or rifting) in central Tibet, we obtained passive-source seismic observations for one year along a profile across the Yadong-Gulu Rift (Fig.…”

Section: Introductionmentioning

confidence: 99%

Normal faulting from simple shear rifting in South Tibet, using evidence from passive seismic profiling across the Yadong-Gulu Rift

et al. 2013

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Finite frequency tomography in southeastern Tibet: Evidence for the causal relationship between mantle lithosphere delamination and the north–south trending rifts

Cited by 78 publications

References 55 publications

Earthquake swarms near eastern Himalayan Syntaxis along Jiali Fault in Tibet: A seismotectonic appraisal

Earthquake swarms near eastern Himalayan Syntaxis along Jiali Fault in Tibet: A seismotectonic appraisal

Seismic P-wave tomography in eastern Tibet: Formation of the rifts

Normal faulting from simple shear rifting in South Tibet, using evidence from passive seismic profiling across the Yadong-Gulu Rift

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