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Acta Seismologica Sinica(English Edition) 2004年第z1期17卷 1-8页

作者： SHI Yao-lin(石耀霖) ZHANG Jian(张健) laboratory of Computational geodynamics Graduate School of Chinese Academy of Sciences Beijing 100039China

There are three cases of variation of trench location possible to occur during subduction: trench fixed, trench ad- vancing, and trench retreating. Retreat of trench may lead to back-arc extension. The Pacific plate subducts at low angle beneath the Eurasia plate, tomographic results indicate that the subducted Pacific slab does not penetrate the 670 km discontinuity, instead, it is lying flat above the interface. The flattening occurred about 28 Ma ago. Geo- dynamic computation suggests: when the frontier of the subducted slab reaches the phase boundary of lower and upper mantle, it may be hindered and turn flat lying above the boundary, facilitates the retreat of trench and back-arc extension. Volcanism in northeastern China is likely a product of such retreat of subduction, far field back-arc extension, and melting due to reduce of pressure while mantle upwelling.

关键词： back-arc basin Cenozoic volcano geodynamics northeastem China

Finite element simulation of deformation and stress changes of Kalpin-Kemin fault system in the Southwest Tianshan Orogenic Belt

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Science China Earth Sciences 2022年第5期65卷 863-873页

作者： Zitao WANG Huai ZHANG Qiu MENG Yaolin SHI Key laboratory of Computational geodynamics University of Chinese Academy of SciencesBeijing 100049China

Under the shadow of the far-field effect of the India-Eurasia collision,the Tianshan orogenic belt underwent tectonic re-activation in the Cenozoic,accompanied by strong tectonic deformation and frequent large *** by two rigid cratonic blocks located in its north and south,a series of marginal foreland fold-and-thrust belts are developed within the Tianshan orogenic belt and continue to develop to the bilateral pull-apart ***,the faults in the orogenic belt are *** deformation caused by thrust-related structure accounts for larger than 50%of the total convergence of the Tianshan Mountains,which results in the most active structure with large earthquakes in the Tianshan ***,it is of great significance to study the dynamic process of the newly generated and reactivated thrust-nappe structures in Tianshan orogen via numerical *** paper selects a classical cross-section profile in the western segment of the Southwest Tianshan Mountains,which contains the Kalpin-Maidan-Nalati-Kemin fault system from the south to the *** attempt to establish a two-dimensional plane strain,viscoelastic finite element model,by treating the regional faults as a whole fault system and considering the topography,fault geometry,and GPS *** displacement and stress fields of the model are retrieved,the short-term cumulative deformation field of the overall fault system is analyzed,and the rate of Coulomb failure stress change of each fault is also *** results show that the deformation is concentrated in the middle and southern parts of the Southwest Tianshan *** contrast,the deformation of the Kemin fault in the north is relatively *** to the Coulomb failure stress changes of these four faults and the historical earthquake catalog,the potential seismicity of each fault is qualitatively *** preliminary results suggest that the possibility of large earthquake occurrence is higher in the

关键词： Tianshan orogenic belt Viscoelastic finite element Coulomb failure stress change Seismicity

Numerical simulation of Martian historical dynamo:Impact of the Rayleigh number on the dynamo state

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Science China Earth Sciences 2009年第3期52卷 402-410页

作者： WANG TianYuan KUANG WeiJia MA ShiZhuang laboratory for Computational geodynamics Graduate University of Chinese Academy of SciencesBeijing 100049China Planetary geodynamics laboratory NASA Goddard Space Flight CenterGreenbeltMD 20771USA

The observed Mars remnant magnetism suggests that there was an active dynamo in the Martian core. We use the MoSST core dynamics model to simulate the Martian historical dynamo, focusing on the variation of the dynamo states with the Rayleigh number Ra (a non-dimensional parameter describing the buoyancy force in the core). Our numerical results show that the mean field length scale does not vary monotonically with the Rayleigh number, and the field morphology at the core mantle boundary changes with Rayleigh number. In particular, it drifts westward with a speed decreasing with Rayleigh number.

关键词： Mars magnetic field Rayleigh number dynamo

Three-dimensional numerical simulation of glacial trough forming process

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Science China Earth Sciences 2015年第9期58卷 1656-1668页

作者： YANG ShaoHua SHI YaoLin Key laboratory of Computational geodynamics of Chinese Academy of Sciences University of Chinese Academy of Sciences

The glacial trough is a common glacier erosion landscape, which plays an important role in the study of glacier erosion processes. In a sharp contrast with the developing river, which is generally meandering, the developing glacial trough is usually wide and straight. Is the straightness of the glacial trough just the special phenomenon of some areas or a universal feature? What controls the straightness of the glacial trough? Until now, these issues have not been studied yet. In this paper, we conduct systematic numerical models of the glacier erosion and simulate the erosion evolution process of the glacial trough. Numerical simulations show that:(1) while the meandering glacier is eroding deeper to form the U-shaped cross section, the glacier is eroding laterally. The erosion rate of the ice-facing slope is bigger than that of the back-slope.(2) The smaller(bigger) the slope is, the smaller(bigger) the glacier erosion intensity is.(3) The smaller(bigger) the ice discharge is, the smaller(bigger) the glacier erosion intensity is. In the glacier erosion process, the erosion rate of the ice-facing slope is always greater than that of the back-slope. Therefore, the glacial trough always develops into more straight form. This paper comes to the conclusion that the shape evolution of the glacial trough is controlled mainly by the erosion mechanism of the glacier. Thereby, the glacial trough prefers straight geometry.

关键词： glacial trough erosion action numerical simulation finite element method

Advances, Problems and Prospects of Modern Geodesy Applied in Tibetan Geodynamic Changes

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Acta Geologica Sinica(English Edition) 2013年第2期87卷 318-332页

作者： SUN Wenke ZHOU Xin Key laboratory of Computational geodynamics of Chinese Academy of Sciences University of Chinese Academy of Sciences

Modern geodetic techniques have developed rapidly in recent years, providing reliable observation data and new effective approaches, and greatly enhancing studies of the Tibetan geodynamics. For instance, the well-known GPS technique has been employed to measure seismic slips for many faults in the Tibetan Plateau. GPS data agree well with the hypothesis of a thickening crust and eastward mass flow. Moreover, absolute gravimetric data have been applied to interpret geophysical phenomena such as crust movement, co-seismic gravity change, GIA, and ground water change. The satellite gravity mission GRACE launched in 2002 provided global gravity models with unprecedentedly high precision and high spatial resolution. It has been used in implementing temporal gravity changes and improving our knowledge of the Earth＇s interior, including lithosphere dynamics, mantle viscosity and rheology, plateau uplift, and subduction processing. It is noteworthy that gravity presents unique advantages for the study of Tibetan geodynamics because of its sensitivity to mass migration and dynamic redistribution. To date, great advances have been made in applying modern geodetic data in studying dynamic changes of Tibetan plateau. For instance, the horizontal displacement field from GPS data revealed dynamical characteristics of the present-day Tibetan plateau. The combination of gravity anomalies and topographic data describe the tectonic characteristics of Tibetan plateau. The combination of gravity data and GPS data show present properties of the Tibetan plateau such as crust thickening, Moho＇s subsidence, and plateau uplift. GRACE data were used to estimate the distribution of ice/snow melting. These results demonstrate that mere application of integrated geodetic data as well as geophysical methods and numerical simulations can enhance our knowledge of Tibetan plateau dynamics. It must be pointed out that GRACE data include various geophysical signals such as crust vertical movement, d

关键词： modern geodesy gravity GPS gravity satellite geodynamics Tibetan plateau

Lithospheric Thermal Isostasy of North Continental Margin of the South China Sea

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Journal of China University of Geosciences 2009年第1期20卷 95-106页

作者：陈石张健孙玉军石耀霖 laboratory of Computational geodynamics Graduate University of Chinese Academy of SciencesBeijing 100049 China

Accompanied with rifting and detaching of the north continental margin of the South China Sea, the crust and the lithosphere become thinner away from the continental margin resulting from the tectonic activities, such as tensile deformation, thermal uplift, and cooling subsidence, etc.. Integrated with thermal, gravimetric, and isostatic analysis techniques, based on the seismic interpretation of the deep penetration seismic soundings across the northern margin of the South China Sea, we reconstructed the lithospheric thermal structure and derived the variation of the crust boundary in the east and west parts of the seismic profile by using gravity anomaly data. We mainly studied the thermal isostasy problems using the bathymetry of the profiles and calculated the crust thinning effect due to the thermal variety in the rifting process. The results indicate that the thermal isostasy may reach 2.5 km, and the compositional variations in the lithospheric density and thickness may produce a variation of 4.0 km. Therefore, the compositional isostatic correction is very important to recover the relationship between surface heat flow and topography. Moreover, because of the high heat flow characteristic of the continental margin, building the model of lithospheric geotherm in this region is of great importan for studying the Cenozoic tectonic thermal evolution of the north passive continental margin of the South China Sea.

关键词： north continental margin of the South China Sea lithosphere geothermal thermal isostasy.

Numerical investigation on the geodynamical mechanism of the first major shock of 2006 Pingtung M_w7.0 earthquake

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Science China Earth Sciences 2011年第5期54卷 631-639页

作者： SUN YuJun ZHANG Huai SHI YaoLin laboratory of Computational geodynamics Graduate University of Chinese Academy of Sciences Beijing 100049 China

A strong Mw7.0 earthquake struck Pingtung offshore of Talwan on December 26, 2006. It consisted of two major events with an 8-minute interval. The first major shock occurred at 12：26 UTC. Focal mechanism results from Harvard, USGS, and BATS all indicated that the first major shock was a normal fault earthquake and the second one was dominated by strike-slip offsets. The location of the epicenter varied greatly in depth in different analyses. The latest results showed that the focal depth of the first shock was most probably around 40-44 km, placing the epicenter in the lithospheric mantle. However, this is not a location where earthquakes usually occur. To explore the geodynamical mechanism of this event, we carded out 2D finite element method （FEM） numerical experiments. Our primary results indicate that the geodynamical background, as well as the formation of Pingtung earthquake, is a consequence of the collision between Luzon arc and Chinese continental margin. Although Taiwan Island is in the shadow of NW-SE trending compressive collision zone, the existence of ductile lower crust leads to the decoupling between upper crust and lithospheric mantle. As lithospheric mantle subducts to the depth of around 250 km, the upper part of the bending subduction slab puts itself in an extensional state. The extensional stress from bending induced the occurrence of this normal fault earthquake at the critical point.

关键词： Pingtung earthquake geodynamical mechanism FEM simulation hierarchical rheology geodynamics

Arrival time measurements of first arrival phases P and PKIKP using the method of fixed scale wavelet transformation ratio

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Acta Seismologica Sinica(English Edition) 2005年第4期18卷 410-418,499页

作者：何小波周蕙兰 Computational geodynamics laboratory Graduate School of Chinese Academy of Sciences Beijing 100049 China

The arrival times of first teleseismic phases are difficult to be measured precisely because of slowly and gradually changed onsets and weak amplitudes. The arrival times measured manually are usually behind the real ones. In this paper, using the ratio method of fixed scale wavelet transformations improved by us, the arrival times for the first arrival phases (such as P and PKIKP) at the teleseismic and far-teleseismic distances were measured. The results are reasonable and reliable based on the analysis and discussion of the reliabilities and errors.

关键词： Morlet wavelet wavelet transformation ratio first arrival phase first arrival time signal to noise ratio

Unified representation of gravitation field in consideration of effect of ellipsoid flattening

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Chinese Science Bulletin 1997年第19期42卷 1631-1636页

作者： ZHU Zhuowenlaboratory for Modern geodynamics, Wuhan Technical University of Surveying and Mapping, Wuhan 430079, China laboratory for Modern geodynamics Wuhan Technical University of Surveying and Mapping Wuhan China

THE theory of unified representation of gravitation field proposed by the author is modelledupon spherical approximation for disturbing potential. It is a common knowledge that sphericalapproximation should lead to a result involving an innate error. This kind of error is tolerableonly for general application, an ellipsoidal correction has to be taken into account in case of de-siring for a result with higher accuracy. The purpose of this note is to try to make an

关键词： unified representation of gravitation field interior Dirichlet’ s problem of biharmonic equation for ellipsoidal domain radial shrinking mapping approximation problem anomalous density.

Key geodynamic processes and driving forces of Tethyan evolution

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Science China Earth Sciences 2023年第12期66卷 2666-2685页

作者： Zhong-Hai LI Fengyuan CUI Shuting YANG Xinyi ZHONG Key laboratory of Computational geodynamics College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China

Tethys tectonic system has experienced a long-term evolution history,including multiple Wilson cycles;thus,it is an ideal target for analyzing plate tectonics and *** evolution is typically characterized by a series of continental blocks that separated from the Gondwana in the Southern Hemisphere,drifted northward,and collided and accreted with Laurasia in the Northern *** this process,the successive opening and closing of multistage Tethys oceans(e.g.,Proto-Tethys,Paleo-Tethys,and Neo-Tethys)are considered core parts of the Tethyan ***,focusing on the life cycle of an oceanic plate,four key geodynamic processes during the Tethyan evolution,namely,continental margin breakup,subduction initiation(SI),Mid-Ocean Ridge(MOR)subduction,and continental collision,were highlighted and dynamically analyzed to gather the following insights.(1)Breakup of the narrow continental margin terranes from the northern Gondwana is probably controlled by plate subduction,particularly the subduction-induced far-field *** breakup of the Indian continent and the subsequent spreading of the Indian Ocean can be attributed to the interactions between multiple mantle plumes and slab drag-induced far-field stretching.(2)Continental margin terrane collision-induced subduction transference/jump is a key factor in progressive Tethyan evolution,which is driven by the combined forces of collision-induced reverse push,far-field ridge push,and mantle flow ***,lithospheric weakening plays an important role in the occurrence of SI.(3)MOR subduction is generally accompanied by slab *** case of the considerably reduced or temporary absence of slab pull,mantle flow traction may contribute to the progression of plate *** subduction can dynamically influence the overriding and downgoing plates by producing important and diagnostic geological records.(4)The large gravitational potential energy of the Tibetan Plateau indicat

关键词： Continental margin breakup Subduction initiation Mid-Ocean Ridge subduction Continental collision Tethys geodynamics