Seismic attenuation tomography in southwestern China: Insight into the evolution of crustal flow in the Tibetan Plateau

Dai, Andy; Tang, Chi‐Chia; Liu, Lei; Xu, Rui

doi:10.1016/j.tecto.2020.228589

Cited by 16 publications

(14 citation statements)

References 49 publications

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“…However, there is a high-velocity body in the South Chuandian Block that separates these two low-velocity anomalies. The high-velocity body in the South Chuandian Block is also confirmed by other data and methods (Bao et al, 2015;Qiao et al, 2018;Dai et al, 2020;Li et al, 2020;Yang et al, 2020;Han et al, 2022). This high-velocity body is located in the inner zone of the ELIP and may be at the lithosphere scale (Profiles BB' and EE' in Figure 6), which is speculated to be related to magma intrusion and underplating when the ELIP formed (Chen et al, 2015;Xu et al, 2015).…”

Section: The Deformation Mechanism In the Crustsupporting

confidence: 74%

“…Frontiers in Earth Science frontiersin.org decades and have obtained many important results. Two significant low-velocity anomalies (Yao et al, 2008;Bao et al, 2015;Zhang et al, 2020;Han et al, 2022) with high conductivity (Bai et al, 2010;Li et al, 2019) and high seismic attenuation (Zhao et al, 2013;Dai et al, 2020) have been detected in the mid-lower crust by seismic and magnetotelluric tomography. The two low-velocity anomalies are separated by a high-velocity anomaly located in the South Chuan-Dian Block (Bao et al, 2015;Xu et al, 2015;Qiao et al, 2018;Yang et al, 2020;Zhang et al, 2020;Han et al, 2022).…”

Section: Introductionmentioning

confidence: 98%

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3-D azimuthal anisotropy structure reveals different deformation modes of the crust and upper mantle in the southeastern Tibetan Plateau

2023

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The tectonic evolution and deformation process of the southeastern Tibetan Plateau has been one of the focuses of the geoscience community in recent decades. However, the crustal and mantle deformation mechanism in the southeastern Tibetan Plateau is still under debate. Seismic anisotropy inferred from surface wave tomography could provide critical insights into the deformation mechanism of the Earth’s tectonosphere. Here, we constructed a 3-D azimuthal anisotropy velocity model with Rayleigh wave phase velocity dispersion data from 132 permanent stations to analyze the deformation modes in the southeastern Tibetan Plateau. In the upper crust, the azimuthal anisotropy near the main strike-slip faults exhibits strong magnitude with fast axis subparallel to the fault strike, which is consistent with the rigid block extrusion pattern. In the mid-lower crust, two low-velocity anomalies appeared beneath the Sonpan-Ganzi Terrane and Xiaojiang Fault zone with strong azimuthal anisotropy, which may indicate ductile deformation of the weak mid-lower crust. However, the two low-velocity anomalies are separated by a high-velocity barrier with weak azimuthal anisotropy in the inner zone of the Emeishan large igneous province. In the upper mantle, the anisotropy pattern is relatively simple in the rigid Yangtze Craton and mainly represents fossil anisotropy. In the southern part, the lithosphere thinned beneath the Indochina and Cathaysia Blocks, and the anisotropy is plausibly caused by the upwelling and lateral flows of upwelling hot asthenospheric materials.

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Section: The Deformation Mechanism In the Crustsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 98%

3-D azimuthal anisotropy structure reveals different deformation modes of the crust and upper mantle in the southeastern Tibetan Plateau

2023

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“…The regional residual gravity (Y. Deng et al., 2014c) and high resistivity (X. Li et al., 2020) here are also consistent with a plume‐modified lithosphere. The minimum in

Δ t_{p}^{*}

is colocated with a maximum in Qp at crustal depths (Dai et al., 2020) and a maximum in resistivity (X. Li et al., 2020), confirming the plume‐modified lithosphere. Consequently, lithosphere strengthened by a Permian mantle plume (Y. Deng et al., 2017; X. Xu et al., 2020) could be the source of the low attenuation in this region.…”

Section: Discussionmentioning

confidence: 86%

“…Geophysical studies suggest that plume activity resulted in crustal underplating with high Vp, Vs, density and low attenuation in the crust (Y. Chen et al, 2015;Dai et al, 2020;. The regional residual gravity (Y.…”

Section: The Sichuan Basin and Chuandian Fragmentmentioning

confidence: 99%

New Insights Into the Heterogeneity of the Lithosphere‐Asthenosphere System Beneath South China From Teleseismic Body‐Wave Attenuation

Deng

Byrnes

Bezada

2021

Geophysical Research Letters

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The long tectonic history of South China includes Precambrian amalgamation and several Phanerozoic episodes of lithospheric modification. It formed via the collision of the Yangtze and Cathaysia blocks (Figure 1a) along the Jiangshan-Shaoxing fault in the Neoproterozoic (e.g. Z. X. Li et al., 2002). After amalgamation, three important tectonothermal events occurred in South China, namely the Wuyi-Yunkai (Early Paleozoic), Indosinian (Triassic), and Yanshanian (Jurassic-Cretaceous) events (Y. Wang et al., 2013b), often called "movements" in Chinese literature. Each event led to extensive deformation and magmatism across South China. The lingering effects of these events on lithospheric structure have been investigated by many geophysical studies, including models of P wave velocity structure from active seismic profiles (Y.

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“…The attenuation factors are not incorporated in the construction of SGTs database by curvilinear-grid finite-difference simulation in this study. We estimate the average quality factors of P-and surface waves (Q P ≈ 500 and Q S ≈ 500) at the depth of 5 km in this region from Dai et al (2020). The distances from the Changning earthquake to 17 broadband stations range from 70 km to 370 km.…”

Section: Discussionmentioning

confidence: 99%

Centroid Moment Tensor of the 2019 MW 5.7 Changning Earthquake Refined Using 3D Green’s Functions Considering Surface Topography

Huo

Zhang

2021

Front. Earth Sci.

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The MW 5.7 Changning earthquake occurred in southern Sichuan basin on 17 June 2019 and was the largest event ever recorded in this region. There are still some arguments existing about the causes of the earthquake and its possible links with water injections. Many studies on this earthquake have been performed, but the event depths obtained among them are significantly different and the source mechanisms also exhibit variations. In this study, we design an inversion scheme and use 3D Green’s functions considering the rugged topography of this region to determine the event location and moment tensor of the Changning earthquake based on waveform fittings. The 3D model can reduce the uncertainty due to the approximation of 1D model and better constrain the solutions. The latitude and the longitude of event location are 28.34°N and 104.82°E respectively and the depth is 3.14 km. The nodal plane solutions are strike 295°/dip 88°/rake 14° and strike 204°/dip 76°/rake 178°. The percentages of DC, CLVD and ISO components are 10, −83, and −7%, respectively. The good waveform fittings at 17 broadband stations indicate the reliability of the source mechanism in this study.

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Seismic attenuation tomography in southwestern China: Insight into the evolution of crustal flow in the Tibetan Plateau

Cited by 16 publications

References 49 publications

3-D azimuthal anisotropy structure reveals different deformation modes of the crust and upper mantle in the southeastern Tibetan Plateau

3-D azimuthal anisotropy structure reveals different deformation modes of the crust and upper mantle in the southeastern Tibetan Plateau

New Insights Into the Heterogeneity of the Lithosphere‐Asthenosphere System Beneath South China From Teleseismic Body‐Wave Attenuation

Centroid Moment Tensor of the 2019 MW 5.7 Changning Earthquake Refined Using 3D Green’s Functions Considering Surface Topography

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