Present-day horizontal deformation status of continental China and its driving mechanism

Abstract

Based on velocity data of 933 GPS sites and using the methods of Ordinary Kriging interpolation and shape function derivation, this study has obtained the strain rate field of continental China in the spherical coordinates. In comparison with previous research results, it is found that such a strain rate field can be described by both the continuous deformation and block motions in the continent. The Tibetan Plateau and Tianshan region are characterized by continuous deformation which is distributed across the whole area. Within the blocks of South China, Tarim, Ordos, and Northeast China, little crustal deformation and deformation occurs primarily on the faults along their boundaries, which can be explained by the model of block motion. In other regions, such as the Yinshan-Yanshan block, North China block, and East Shandong-Yellow Sea, deformation patterns can be explained by both models. Besides, from southwest to northeast of continental China, there are three remarkable extensional zones of NW trending. These results imply that the NNE directed push of the India plate is the primary driving force accounting for the internal deformation of continental China. It produces the uplift, horizontal shortening and vertical thickening of the Tibetan Plateau as well as radiation-like material extrusion. Of these extruded materials, one part accommodates the eastward "escape" of other blocks, generating convergence and compression of western China and widespread extension and local complicated deformation in eastern China under the joint action of the surrounding settings. The other part opens a corridor between the South China block and Tibetan Plateau, flowing toward southeast to the Myanmar range arc and filling the gap there which is produced by back-arc extension due to plate subduction.

Dynamic Rupture Simulations of the 2008 Mw 7.9 Wenchuan Earthquake by the Curved Grid Finite‐Difference Method

“…There is no obvious evidence showing that the orientation of principal stress could have changed nearly 90° from the start to the end of the Wenchuan earthquake fault within approximately 300 km. The tectonic stress field derived by previous works undertaken before the Wenchuan earthquake (e.g., Chen, ; Deng et al, ; Wang et al, ) suggested that the tectonic stress field does not change significantly in the spatial region hosting the Wenchuan earthquake. Thus, in this work, we use a homogeneous tectonic stress field in the entire calculation volume, except that the stress varies with depth, considering depth‐dependent lithostatic pressure.…”

“…Thus, in this work, we use a homogeneous tectonic stress field in the entire calculation volume, except that the stress varies with depth, considering depth‐dependent lithostatic pressure. The orientation of the maximum horizontal compressional stress σ H is set to N280°E (Figure ), according to various studies on the tectonic stress state in the Longmen Shan region (Chen, ; Deng et al, ; Wang et al, ). Although there are some works suggesting the stress filed maybe rotate along the Beichuan fault (Gao et al, ), we use the simple uniform stress filed (with the maximum horizontal compressional stress pointing to N280°E [Figure ]) along the fault plane.…”

Rupture mechanism and seismotectonics of the Ms6.5 Ludian earthquake inferred from three‐dimensional magnetotelluric imaging

“…Based on our 3‐D electrical model, combining with GPS [ Liang et al, ; Chen , ], thermal structure [ Wei and Zang , ], and seismic survey results [ Bao et al, ], a concept model is proposed to interpret geodynamic process the Ludian earthquake (Figure ). The SSE trending motion of the CDB defines the dominant left‐lateral slip of the NW trending faults in Ludian earthquake region.…”

“…However, both the field investigation and focal mechanism solution indicate that the study region has a few tensional deformation [ Xu et al, , ; Li et al, ]. The results of the dilatation strain calculated from GPS data also demonstrate that the Ludian earthquake occurred in a tensional deformation area [ Chen , ]. The SSE trending motion of the CDB defines the dominated deformation characteristics of the study region, namely, NW trending left‐lateral slip and NE trending right‐lateral slip.…”

Three‐Dimensional Electrical Structure Beneath the Epicenter Zone and Seismogenic Setting of the 1976 Ms7.8 Tangshan Earthquake, China

“…(d) The seismogenic structure is neither the Cangdong fault nor the Douhe fault in the shallow crust (J. Xu & Ji, 2015), but rather a steep fault buried in the deep crust under the earthquake area (G. D. Liu, 1994;B. J. Liu et al, 2011;C.…”