3D electrical structure and crustal deformation of the Lajishan Tectonic Belt, Northeastern margin of the Tibetan Plateau

Zhao, Lingqiang; Zhan, Yan; Wang, Qingliang; Sun, Xiangyu; Hao, Ming; Zhu, Yongnan; Han, Jin

doi:10.1016/j.jseaes.2021.104953

Cited by 7 publications

(4 citation statements)

References 42 publications

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“…We use a horizontal cell size of 3.0 × 3.0 km to parameterize the initial model of the central area, and get 26 × 52 central grid cells and expand the grid by another 10 in each of the four outer directions using 1.5x multipliers, finally 46 × 72 horizontal grid cells are produced. The vertical grid design and inversion parameters are similar to those of previous studies (Cai et al., 2017; Sun, Zhan, Unsworth, et al., 2020; L. Zhao et al., 2021). The grid thickness of the first layer is 10 m, and the grid thickness varies at different proportions in depth.…”

Section: ‐D Inversion and Electrical Structuresupporting

confidence: 69%

Three‐Dimensional Electrical Structure and Magma System of the Monogenetic Longgang Volcanic Field, Northeast China, Inferred From Broadband Magnetotelluric Data

Zhao

Zhan

et al. 2022

JGR Solid Earth

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The Longgang volcanic field (LVF) is one of the largest intraplate monogenetic volcanic regions in China, and eruption lasted from the early Pleistocene to the Holocene. Previous research shows that the LVF is not only experiencing rapid surface uplift but also significant seismic activity. The magmatic system under the LVF poses a hazard of potential eruption. The three‐dimensional electrical resistivity model developed by magnetotelluric data shows that the upper crust of the LVF and the surrounding areas hosts a high‐resistivity body composed of volcanic rocks produced by massive eruptions during past volcanic episodes. There are two main high‐conductivity structures below the depth of 10 km in the southwest and northeast of the LVF. The two structures merge in the lower crust and extend to the mantle. We interpret these high‐conductivity structures to be magmatic channels (the resistivity of C1 is 20–50 and C2 is 5–20 Ωm). Magmatic channel upwelling along the C1 may have caused the eruption of the Jinlongdingzi volcano 1,700 years ago. The C2 magmatic channel in the northeast of the LVF is larger and lower resistivity than C1. The modern surface uplift and seismicity in the LVF is a result of upwelling and intrusion along C2 magmatic channel. The Hunjiang fault passing through the LVF may also influence the upwelling of material along the C2 magmatic channel, posing a hazard of future eruption in the LVF. The high‐conductivity structures in the LVF pass through the Moho and extend to the upper mantle and are connected from the top to bottom. Combined with geochemical data, we speculate that the magmatic system in the LVF may directly come from the upper mantle and the magma has experienced rapid ascent with limited crustal internal evolution.

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Section: ‐D Inversion and Electrical Structuresupporting

confidence: 69%

Three‐Dimensional Electrical Structure and Magma System of the Monogenetic Longgang Volcanic Field, Northeast China, Inferred From Broadband Magnetotelluric Data

Zhao

Zhan

et al. 2022

JGR Solid Earth

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“…In recent years, with the application of supercomputers and the increasingly mature and practical MT 3D inversion algorithms (Siripunvaraporn et al, 2005;Egbert et al, 2012;Kelbert et al, 2014), 3D inversion technology has been widely used in the practical research of various MT detections (Dong et al, 2014;Sun et al, 2019Sun et al, , 2020Zhao et al, 2022).…”

Section: Introduction To the Mt Methodsmentioning

confidence: 99%

“…The electrical structural information of the crust obtained using the magnetotelluric (MT) method can provide a basis for the division of block units (Chen., 1990). It is an important deep geophysical method used to detect the deep extension characteristics of the fault zone and has been widely used (Zhao et al, 2012;Cai et al, 2017;Yu et al, 2017;Wang et al, 2018;Hu et al, 2020;Sun et al, 2020;Li L. et al, 2021;Ye et al, 2021;Zhan et al, 2021;Zhao et al, 2021;Chang et al, 2022;Zhao et al, 2022). Predecessors have completed much MT exploration work in the Ordos Block and its surrounding areas.…”

Section: Introductionmentioning

confidence: 99%

Deep Electrical Structure of the Langshan Mountain-Linhe Basin Area on the Northwest Edge of the Ordos Block, China

et al. 2022

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A series of fault depression structures have developed around the Ordos Block. The Langshan Mountain-Linhe Basin area (LLA), located on the northwest edge of the Ordos Block, is a typical, normal tension fault system. A geological survey shows that the Langshan Piedmont fault (LPF) in this area has a large slip rate and indicates risk of earthquake preparation. Broadband magnetotelluric (MT) exploration research was recently carried out across the LLA in the NW–SE direction, and the three-dimensional deep electrical structure thus obtained revealed that the LPF in the LLA is an evident electrical boundary zone on the whole crustal scale and is the main boundary fault of the primary structural block of the Alxa and Ordos Blocks. The MT results also show that the Linhe Basin and Ordos Block belong to the same tectonic basement. The Linhe and Dengkou faults belong to the internal faults of the Ordos Block. The upper crust of the Langshan Mountain on the west side of LPF is characterized by high-resistivity, the middle and lower crust have a low-resistivity layer, and the Linhe Basin on the east side has a Cenozoic low-resistivity sedimentary layer of approximately 10 km thick, which reveals that the Linhe Basin is a faulted basin with sedimentary thickness around the Ordos Block. This indicates that the LLA has experienced continuous and strong tension, normal fault depression sedimentary activities since the Cenozoic era. The current Global Positioning System velocity field shows that there is an apparent NW–SE acceleration zone in the LLA. The leveling data indicate that Linhe Basin shows a subsidence trend relative to the Ordos Block, indicating that the area is undergoing continuous NW–SE tension and faulting. It is speculated that there is a risk of earthquake preparation in the LPF.

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“…The Lajishan and Liupanshan faults are two nearly parallel arc‐shovel‐shaped faults (Min et al., 2023; Zhao et al., 2022). For the Lajishan fault, our inversions using three data sets yield consistent results.…”

Section: Major Fault Slip Rate Deficit and Coupling Ratiomentioning

confidence: 99%

Present‐Day 3D Crustal Deformation of the Northeastern Tibetan Plateau From Space Geodesy

Wu,

Ge,

Liu

et al. 2024

Geophysical Research Letters

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High‐resolution present‐day earth surface deformation maps from satellites provide important data constraints, which help us better understand tectonic processes and analyze seismic hazards. Here, we use Sentinel‐1 Radar images (2014–2020) and accurate positioning measurements (2009–2019) to get a high‐resolution three‐dimensional earth surface velocity map for the northeastern Tibetan Plateau, and we invert the slip rate and coupling ratio of major regional faults. We find ∼4 mm/yr uplift along an arc from the Qilianshan to Lajishan, relative to the neighboring low‐elevation area to the east, which indicates ongoing rapid orogeny. We find transient deformation along the Laohushan and 1920 M8.5 Haiyuan rupture segments of the Haiyuan fault, whereas the western Haiyuan, southern Liupanshan, central Lajishan and central‐western West Qinling faults are essentially locked above 15–20 km, suggesting a potentially high seismic hazard.

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3D electrical structure and crustal deformation of the Lajishan Tectonic Belt, Northeastern margin of the Tibetan Plateau

Cited by 7 publications

References 42 publications

Three‐Dimensional Electrical Structure and Magma System of the Monogenetic Longgang Volcanic Field, Northeast China, Inferred From Broadband Magnetotelluric Data

Three‐Dimensional Electrical Structure and Magma System of the Monogenetic Longgang Volcanic Field, Northeast China, Inferred From Broadband Magnetotelluric Data

Deep Electrical Structure of the Langshan Mountain-Linhe Basin Area on the Northwest Edge of the Ordos Block, China

Present‐Day 3D Crustal Deformation of the Northeastern Tibetan Plateau From Space Geodesy

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