Absolute Motion Research Articles

Lithospheric deformation revealed by teleseismic phases SKS PKS and SKKS splitting in the NE margin of the Tibetan plateau

The NE margin of the Tibetan plateau influenced by multiple blocks, the regional dynamic model and lithospheric deformation characteristics are still controversial. In this study, 15 years data from permanent broadband seismic stations of the seismic network in the study area were adopted for splitting analyses of teleseismic phases XKS (SKS PKS and SKKS, shortly named XKS) using a grid search method, longer observations provided each station with a large number of clear seismic phases. The results show that the fast wave directions of XKS splitting are oriented toward WNW or NW, with reference to the direction of absolute plate motion, the lithospheric deformation is dominantly driven by the asthenosphere, although there are local variations. On both sides of the Haiyuan fault zone, there is a noticeable variation in lithospheric azimuthal anisotropy, further enhances the possibility that it is an extended boundary of the Tibetan plateau. Rheological anisotropic features on the western side of the Ordos block emphasize the obstruction of the rigid Ordos lithosphere. The crust and mantle seem to be coupled below the Qinling orogen, possibly related to the lateral movement of lithospheric material. However, in the Hexi corridor, there may be layered anisotropy within the lithosphere, which is inferred to relate to the subductions of the Alxa block and the Qilian orogen. The thicker lithosphere on the southern margin of the Alxa block may influence the asthenospheric flow. In addition, anisotropy results at the southeastern edge of the Alxa block and the Yinchuan graben reflect the possibility that the lithosphere may be characterized by a combination of horizontal and vertical movements. These results have greatly improved our understanding of the dynamic models and lithospheric deformation characteristics of the northeastern margin of the Tibetan plateau and adjacent areas.

Investigating concurrent validity of inertial sensors to evaluate multiplanar spine movement

Inertial measurement units (IMUs) offer a portable and inexpensive alternative to traditional optical motion capture systems, and have potential to support clinical diagnosis and treatment of low back pain; however, due to a lack of confidence regarding the validity of IMU-derived metrics, their uptake and acceptance remain a challenge. The objective of this work was to assess the concurrent validity of the Xsens DOT IMUs for tracking multiplanar spine movement, and to evaluate concurrent validity and reliability for estimating clinically relevant metrics relative to gold-standard optical motion capture equipment. Ten healthy controls performed spine range of motion (ROM) tasks, while data were simultaneously tracked from IMUs and optical marker clusters placed over the C7, T12, and S1 vertebrae. Root mean square error (RMSE), mean absolute error (MAE), and intraclass correlation coefficients (ICC2,1) were calculated to assess validity and reliability of absolute (abs; C7, T12, and S1 sensors) and relative joint (rel; intersegmental thoracic, lumbar, and total) motion. Overall RMSEabs = 1.33°, MAEabs = 0.74° ± 0.69, and ICC2,1,abs = 0.953 across all movements, sensors, and planes. Results were slightly better for uniplanar movements when evaluating the primary rotation axis (prim) absolute ROM (MAEabs,prim = 0.56° ± 0.49; ICC2,1,abs,prim = 0.999). Similarly, when evaluating relative intersegmental motion, overall RMSErel = 2.39°, MAErel = 1.10° ± 0.96, and ICC2,1,rel = 0.950, and relative primary rotation axis achieved MAErel,prim = 0.87° ± 0.77, and ICC2,1,rel,prim = 0.994. Findings from this study suggest that these IMUs can be considered valid for tracking multiplanar spine movement, and may be used to objectively assess spine movement and neuromuscular control in clinics.

An efficient method for measuring and identifying geometric and dynamic errors in dual five-axis machine tools

The dual five-axis machining machine is state-of-the-art equipment designed for producing thin-walled aerospace parts like skins and panels. It comprises two five-axis machine tools with mirrored synchronous motions: one bi-rotary machine for milling and the other machine for follow-up support. The high absolute accuracy of the five-axis machine tools themselves and the high synchronous motion accuracy between the two machines are both crucial to ensure machining accuracy. This paper proposes an efficient method to measure and identify geometric and dynamic errors of dual five-axis machine tools. Using the R-test combined with three measurement trajectories to measure the absolute motion error of two five-axis machine tools and the synchronous motion error between the two machines. The designed trajectories include the main rotary axis linkage conditions and can fully reflect the primary motion forms of the dual five-axis machine tool. The main position-independent geometric errors and rotational axis linkage dynamic errors are identified by converting quasi-static and dynamic measurement data from three different trajectories into a unified reference coordinate system. The entire process requires only one instrument installation, effectively avoiding time-consuming repetitive installations and calibration processes while reducing the impact of installation errors on results. The effectiveness of the proposed method for measuring and identifying the geometric and dynamic errors is analyzed combined with Monte Carlo simulation. Experiments were carried out on a dual five-axis mirror milling system (MMS) with a 5000 mm X-stroke. Both simulations and experiments confirmed that the proposed method is efficient in quickly identifying key error sources of the MMS.

Toroidal flow around the Tonga slab moved the Samoan plume during the Pliocene

Abstract Age-progressive seamount tracks generated by lithospheric motion over a stationary mantle plume have long been used to reconstruct absolute plate motion (APM) models. However, the basis of these models requires the plumes to move significantly slower than the overriding lithosphere. When a plume interacts with a convergent or divergent plate boundary, it is often deflected within the strong local mantle flow fields associated with such regimes. Here, we examined the age progression and geometry of the Samoa hotspot track, focusing on lava flow samples dredged from the deep flanks of seamounts in order to best reconstruct when a given seamount was overlying the mantle plume (i.e., during the shield-building stage). The Samoan seamounts display an apparent local plate velocity of 7.8 cm/yr from 0 to 9 Ma, 11.1 cm/yr from 9 to 14 Ma, and 5.6 cm/yr from 14 to 24 Ma. Current fixed and mobile hotspot Pacific APM models cannot reproduce the geometry of the Samoa seamount track if a long-term fixed hotspot location, currently beneath the active Vailulu’u Seamount, is assumed. Rather, reconstruction of the eruptive locations of the Samoan seamounts using APM models indicates that the surface expression of the plume migrated ~2° northward in the Pliocene. Large-scale mantle flow beneath the Pacific Ocean Basin cannot explain this plume migration. Instead, the best explanation is that toroidal flow fields—generated by westward migration of the Tonga Trench and associated slab rollback—have deflected the conduit northward over the past 2–3 m.y. These observations provide novel constraints on the ways in which plume-trench interactions can alter hotspot track geometries.

Динамический анализ двухмассовой механической системы в диссипативной среде с учетом сил инерции

In this paper, a dynamic analysis of a two-mass mechanical system is performed. The aim of this work is to study the effect of the inertial forces of bodies in relative motion within the mechanical system on the motion of this system in a dissipative medium with linear viscous resistance to the motion of one of its bodies (a reference body). The analysis is based on the decomposition of the absolute impulse of the mechanical system into portable and relative components. The resolution shows that the relative inertia forces significantly affect the absolute motion of the mechanical system in a dissipative medium. The equation for such motion is presented, where the total mass of the mechanical system is conditionally concentrated in the reference body. The obtained results and conclusions can be used to solve the problem of two gravitating bodies, one of which is located in a dissipative medium, with the center of mass of the bodies moving relative to the center of the inertial domain. The results are also applicable to three-mass mechanical systems of the inertioid type.

Study of complex motion of a plane point at rotation of a supporting body

The paper studies the kinematic characteristics of the complex motion of a point under the rotation of a supporting body. The trajectory of the point performing complex motion is obtained, and the graphs of changes in absolute velocity, absolute acceleration of the point and their components in time are obtained. The solution of the problem was carried out in Mathcad package, for which the problem formulation and solution was carried out by the matrix method. The use of the mathematical package allowed us to take chronograms of the processes of relative motion of the point, translational motion of the body and absolute motion of the point.

Research of the movement of a material particle on the internal surface of a vertical cylinder that performs planetary motion

Planetary motion of a cylinder is understood as its motion when it is in two rotational motions at the same time: it rotates around its own vertical axis with a constant angular velocity, and the cylinder axis itself rotates with a constant angular velocity around a vertical fixed axis. The movement of the particle will be complex and will consist of its relative movement along the inner surface of the cylinder and the translational movement of the cylinder itself. Such a drive scheme is used in cylindrical sieves for sorting seeds of agricultural crops. Problems on the complex motion of a particle can be successfully solved using the trihedron and Frenet's formulas. The purpose of the study is to establish the complex movement of a material particle along the inner surface of a cylindrical sieve using a trihedron and Frenet's formulas at the same and different angular velocities of transfer and relative rotation of the sieve. A characteristic feature of the application of the trihedron and Frenet formulas is that the independent variable in them is not time t, as is generally accepted in problems of kinematics and dynamics of a point, but the length of the arc s of the directional curve (in our case, a circle of radius R), so the relationship was established the connection between rotational movements through this parameter. The system of differential equations is integrated by numerical methods. An exact analytical solution was found in the case when the motion of the particle stabilizes and its speed becomes constant. The obtained results were visualized. Some regularities of the relative and absolute motion of a particle in a cylindrical sieve were established when the angular velocity of rotation of the cylinder around its own axis is zero and is not equal to zero. In the first case, it was found that the particle on the surface of the cylinder occupies a position at which it is as far as possible from the axis of rotation of the cylinder around a vertical line and then it moves down the plane of the cylinder uniformly accelerated, uniformly or uniformly decelerated until it "sticks" depending on the value angular velocity. In the second case, the particle behaves similarly: it remains at the maximum distance after the motion is stabilized. At the same time, it slides along the surface of the cylinder with a constant relative speed along a helical line. The direction of the rise of the helical line changes to the opposite when the direction of the angular velocity of the cylinder changes. Such movement is possible in a certain range of angular velocities of the particle and the cylinder. As the angular velocity of the particle increases, there comes a moment when it cannot maintain the described state of sliding and begins to move along the surface of the cylinder with stops and is prone to "sticking". This state occurs sooner when the angular velocities of the particle and the cylinder have the same direction, and later when they are directed in opposite directions.

Quasi-Zero Stiffness Vibration Sensing and Energy Harvesting Integration Based on Buckled Piezoelectric Euler Beam.

This paper presents a novel quasi-zero stiffness vibration sensing and energy harvesting integration system for absolute displacement measurements based on a buckled piezoelectric Euler beam (BPEB) with quasi-zero stiffness (QZS) characteristics. On one hand, BPEB provides negative stiffness to the system, thus creating a vibration-free point within the system and transforming the absolute displacement measurement problem into a relative motion sensing problem. On the other hand, during the measurement process, the BPEB collects the vibration energy from the system, which can provide electrical energy for low-power relative motion sensing devices and remarkably suppress the frequency range of the jump phenomenon, thereby further expanding the frequency domain measurement range of the sensing system. The research results have shown that this system can measure the absolute motion signal of the tested object in low-frequency vibration with small excitation. By adjusting parameters such as the force-electric coupling coefficient and damping ratio, the measurement accuracy of the sensing system can be improved. Furthermore, the system can convert the mechanical energy of vibrations into electrical energy to power the surrounding low-power sensors or provide partial power. This could potentially achieve self-powering integrated quasi-zero stiffness vibration sensing, offering another approach and possibility for the automation development in wireless sensing systems and the Internet of Things field.

The Experience Dilemma in Heraclitus' Dialectical Thought

Heraclitus' flux doctrine has been criticized for its unilateral emphasis on absolute motion while neglecting relative stability, which leads to a lack of clear positioning and evaluation of experience in his theory of the unity of opposites. This confusion is evident in various descriptions found in the surviving fragments of Heraclitus and has also sparked debates among subsequent scholars researching Heraclitus' theory of knowledge.

Construction of mathematical model of particle movement by an inclined screw rotating in a fixed casing

Screw conveyors are used to move bulk materials vertically upwards, horizontally, and at an angle to the horizon. The processes that take place when particles are moved by a screw conveyor in vertical and horizontal directions have been studied. There is a significant difference between them: for transportation in the vertical direction, the necessary conditions must be ensured (sufficient angular speed of rotation of the screw), and for horizontal transportation, the movement of the particle occurs at any angular speed of rotation of the screw. Therefore, when changing the inclination of the axis of the screw, there comes a moment when transportation becomes possible, while it was impossible in the vertical direction. This paper considers the movement of a particle under the condition that it simultaneously contacts two surfaces: the moving surface of the screw and the stationary surface of the cylindrical casing in which the screw rotates. Their common line along which the particle slides is a helical line – the periphery of the screw. The particle slides along the helical line of the rotating screw, i.e., it is in relative motion with respect to it. At the same time, it slides along the surface of the casing, relative to which it is in absolute motion. The trajectory of the particle's absolute motion is its sliding track on the casing surface. When constructing differential equations of the relative motion of particles, the forces applied to the particle were taken into account. The initial position was taken to be the vertical direction of the screw to transport the particle upwards. If an auger in a cylindrical casing is tilted from the vertical direction to a certain angle, then all applied forces (except the force of weight) will also tilt to this angle. On the basis of this, generalized differential equations of the relative motion of a particle during its transportation by an inclined screw were built. They made it possible to derive a generalized mathematical model of the movement of a particle by an inclined screw that rotates inside a fixed casing

Water maser distributions and their internal motions in the Sagittarius B2 complex

Abstract We conducted a multi-epoch very long baseline interferometry (VLBI) observation of 22 GHz H2O maser sources, which are associated with the Sagittarius B2 (Sgr B2) complex, one of the most active star-forming regions in the Galactic center. Using the VLBI exploration of radio astrometry (VERA) array, we detected 29, 90, and seven maser features in Sgr B2(North), (Main), and (South), respectively. We also discovered two H2O maser features in Sgr B2 (Mid-North). Moreover, we successfully measured spatial distributions and internal motions of the H2O maser sources in Sgr B2(M). We then discovered that the H2O maser features in Sgr B2(M) are located at the outer edge of H ii regions detected by using the centimeter radio continuum emission, and observationally demonstrated that they have outward motions from the two H ii regions separated by 1′. We obtained an absolute proper motion of (μαcos δ, μδ) = (−2.17 ± 0.03, −2.63 ± 0.06) mas yr−1 and marginally detected a parallax of Sgr B2, which is consistent with other measurements. The absolute proper motion corrected by the internal motions of the H2O maser features implies that the Sgr B2 complex is located at the near side of the Galactic center and is moving toward the positive galactic longitude. We estimate that Sgr B2 is at 160 ± 10 pc in front of Sgr A* by assuming a simple circular orbit of the central molecular zone (CMZ).

Improving the power capture performance of deep-sea two-body counter-rotating wave energy using frequency domain optimization in regular and irregular waves

This paper presents a novel two-body counter-rotating wave energy converter (CR-WEC) designed to power deep-sea exploration equipment. In contrast to conventional two-body structures, which employ relative motion, the CR-WEC powers the Power Take-Off (PTO) via absolute motion to circumvent the issue of a limited working stroke. We present the power equation of CR-WEC in the frequency domain, based on the actuator disk model from the wind turbine field, in order to elucidate the energy absorption characteristics of this type of two-body absorber and investigate the influence of parameters on power acquisition. Experiments conducted as part of this study have confirmed this theory's applicability to the CR-WEC. Through an approximation, we derive the frequency point corresponding to the maximum value of the equation, which we refer to as the Power Maximum Frequency Point (PM-FP) in this paper. Under the external excitation of both regular and irregular waves, we investigate how parameter modification can enhance the absorber's capture characteristics in specific cases. After modifying the parameters according to the principles derived from the aforementioned research, the system's theoretical power output can more than double. In addition, this study's conclusions emphasize the benefits of CR-WEC with cascade expansion. By connecting multiple PTOs in series, power generation can be enhanced.

The Influence of Lithospheric Thickness Variations Beneath Australia on Seismic Anisotropy and Mantle Flow

AbstractRapid plate motion, alongside pronounced variations in age and thickness of the Australian continental lithosphere, makes it an excellent location to assess the relationship between seismic anisotropy and lithosphere‐asthenosphere dynamics. In this study, SKS and PKS shear‐wave splitting is conducted for 176 stations covering the transition from the South Australian Craton to eastern Phanerozoic Australia. Comparisons are made with models of lithospheric thickness as well as numerical simulations of mantle flow. Splitting results show uniform ENE‐WSW aligned fast directions over the Gawler Craton and broader South Australian Craton, similar to the orientation of crustal structures generated during an episode of NW‐SE directed compression and volcanism ∼1.6 billion years ago. We propose that heat from volcanism weakened the lithosphere, aiding widespread lithospheric deformation, which has since been preserved in the form of frozen‐in anisotropy. Conversely, over eastern Phanerozoic Australia, fast directions show strong alignment with the NNE absolute plate motion. Overall, our results suggest that when the lithosphere is thin (<125 km), lithospheric contributions are minimal and contributions from asthenospheric anisotropy dominate, reflecting shear of the underlying mantle by Australia's rapid plate motion above. Further insights from geodynamical simulations of the regional mantle flow field, which incorporate Australian and adjacent upper mantle structure, predict that asthenospheric material would be drawn in from the south and east toward the fast‐moving continental keel. Such a mechanism, alongside interactions between the flow field and lithospheric structure, provides a plausible explanation for smaller‐scale anomalous splitting patterns beneath eastern Australia that do not align with plate motion.

Theoretical and numerical studies on improving absorption power of multi-body wave energy convert device with nonlinear bistable structure

For the energy supplement of deep-sea equipment, we examine a multi-body absolute motion counter-rotating wave energy converter (CR-WEC) in the research. In order to improve the capture efficiency of the absorber, a nonlinear bistable structure is proposed to improve the overall wave-following vibration capability of the CR-WEC. And then, we suggest to employing the harmonic balance method to solve the system dynamics equation in the CR-WEC 2-DOF absolute motion state. Combining the essential assumptions results in an analytical solution that is approximative. The paper also investigates the influence of system-related parameter modifications on absorption efficiency. A multi-degree-of-freedom arrangement with an unaltered overall mass is proposed to further increase the device ability to absorb energy. According to the numerical calculation and simulation results, the combination of 3-DOF state and bistable structure can make the device have the maximum capture width and peak value. In the irregular incident wave under the natural state, the multi-body bistable-linear configuration proposed in this study obtains the highest average absorption power.

Upper Mantle Anisotropy and Flow Beneath the Pacific Ocean Revealed by Differential PS‐SKS Splitting

AbstractUpper mantle anisotropy has been mapped beneath continents at high spatial resolution. Beneath the oceans, however, shear wave splitting constraints on upper mantle anisotropy are sparse, due to the paucity of seismic receivers. A technique that does not require the availability of seismic stations close to the region under study is differential PS‐SKS splitting. Here, we use global wavefield simulations to investigate circumstances under which PS‐SKS splitting can be applied, and then use this technique to measure upper mantle anisotropy beneath the Pacific Ocean basin. Our results demonstrate that upper mantle anisotropy in our study region mostly reflects shearing due to the Pacific plate. North of Fiji, we observe a rotation of fast polarization directions, away from the direction of absolute plate motion of the Pacific plate. This may reflect far‐field mantle flow effects associated with the subduction of the Australian plate beneath the Pacific.

Monitoring absolute vertical land motions and absolute sea-level changes from GPS and tide gauges data over French Polynesia

In this study, we estimate the absolute vertical land motions at three tidal stations with collocated Global Navigation Satellite System (GNSS) receivers over French Polynesia during the period 2007–2020, and obtain, as ancillary results, estimates of the absolute changes in sea level at the same locations. To verify our processing approach to determining vertical motion, we first modeled vertical motion at the International GNSS Service (IGS) THTI station located in the capital island of Tahiti and compared our estimate with previous independent determinations, with a good agreement. We obtained the following estimates for the vertical land motions at the tide gauges: Tubuai island, Austral Archipelago −0.92 ± 0.17 mm/yr, Vairao village, Tahiti Iti: −0.49 ± 0.39 mm/yr, Rikitea, Gambier Archipelago −0.43 ± 0.17 mm/yr. The absolute variations of the sea level are: Tubuai island, Austral Archipelago 5.25 ± 0.60 mm/yr, Vairao village, Tahiti Iti: 3.62 ± 0.52 mm/yr, Rikitea, Gambier Archipelago 1.52 ± 0.23 mm/yr. We discuss these absolute values in light of the values obtained from altimetric measurements and other means in French Polynesia.

A novel approach to control four multi-rotor drones in cooperative paired control using relative Jacobian

AbstractThis work presents a new formulation to holistically control four cooperative multi-rotor drones controlled in two pairs. This approach uses a modular relative Jacobian with components consisting of the Jacobians of each individual drone. This type of controller relies mainly on the relative motion between the drones, consequently releasing unnecessary constraints inherent to the control of drones in absolute motion. We present the derivations of all the necessary equations of the modular relative Jacobian to control the four multi-rotor drones. We also present the derivations of the Jacobian for each drone. We implement our proposed method in the Gazebo RotorS simulation using four hexa-rotor drones modeled from Ascending Technologies called firefly drones. We present the simulation results and analyze them to show the effectiveness of our proposed approach.

Quaternion and Biquaternion Methods and Regular Models of Analytical Mechanics (Review)

The work is of a survey analytical nature. The first part of the work presents quaternion and biquaternion methods for describing motion, models of the theory of finite displacements and regular kinematics of a rigid body based on the use of four-dimensional real and dual Euler (Rodrigues–Hamilton) parameters. These models, in contrast to the classical models of kinematics in Euler–Krylov angles and their dual counterparts, do not have division-by-zero features and do not contain trigonometric functions, which increases the efficiency of analytical research and numerical solution of problems in mechanics, inertial navigation, and motion control. The problem of regularization of differential equations of the perturbed spatial two-body problem, which underlies celestial mechanics and space flight mechanics (astrodynamics), is discussed using the Euler parameters, four-dimensional Kustaanheimo–Stiefel variables, and Hamilton quaternions: the problem of eliminating singularities (division by zero), which are generated by the Newtonian gravitational forces acting on a celestial or cosmic body and which complicate the analytical and numerical study of the motion of a body near gravitating bodies or its motion along highly elongated orbits. The history of the regularization problem and the regular Kustaanheim–Stiefel equations, which have found wide application in celestial mechanics and astrodynamics, are presented. We present the quaternion methods of regularization, which have a number of advantages over Kustaanheimo–Stiefel matrix regularization, and various regular quaternion equations of the perturbed spatial two-body problem (for both absolute and relative motion). The results of a comparative study of the accuracy of numerical integration of various forms of regularized equations of celestial mechanics and astrodynamics in Kustaanheimo–Stiefel variables and Newtonian equations in Cartesian coordinates are presented, showing that the accuracy of numerical integration of regularized equations in Kustaanheimo–Stiefel variables is much higher (by several orders of magnitude) than the accuracy of numerical integration Newtonian equations.

Azimuthal Anisotropy of Receiver Functions in the Central South China Block and its Tectonic Implications

By the H-к stacking of the receiver functions and the splitting of the Pms phases, using seismic data from the Regional Seismic Network and the Huanan Seismic Array, a high-resolution temporary seismic array deployed for 2 years in the study area. This study revealed the strong lateral heterogeneity in crustal structures in the central South China block. Crustal thickness reduces from northwest to southeast, with significant differences across the boundary of sub-blocks. The average crustal Vp/Vs ratio gradually increases from west to east, leading to high values in the coastal region, which suggests that the subduction of the Pacific plate has possibly caused the underplating of magma or the upwelling of upper mantle material. The crustal azimuthal anisotropy of the Dabie orogen and the Jiangnan orogen is generally consistent with the strike of the tectonic belt as well as with the orientation of the absolute plate movement. We suggest that the crustal azimuthal anisotropy of the orogen is related to the extension and deformation of the lithosphere. The anisotropy in the crust is close related to crustal deformation. The orientation in the crust and the upper mantle in the Cathaysia block are generally consistent with the orientation of the absolute plate motion, indicating that the azimuthal anisotropy of the Cathaysia block is related to lithospheric deformation and the under-invasion of upper mantle material.

Crustal anisotropy of the South China block and tectonic implications

Exploiting the teleseismic waveform data from permanent seismic stations distributed in the South China block, we obtained the crustal anisotropy parameters at 51 stations by fitting the azimuthal variations of arrival times of the PMs converted wave of radial receiver functions. The results show the dominant direction of fast wave polarity in the South China block is NW–SE, which is basically consistent with the absolute plate motion direction. Combining the shear wave splitting and GPS results, we speculated that the tectonic extension of the Paleo-Pacific plate subduction dominates the crust–mantle anisotropy, which reflects the large-scale tectonic stress setting of the South China block. The fast wave directions of NE–SW and E–W calculated by a few stations might represent a local complex tectonic environment, and the crustal anisotropy of NE–SW is well related to the tectonic deformation in Paleozoic. The delay time of slow waves caused by crustal anisotropy ranges from 0.14 s to 0.71 s, with an average of 0.33 s. The delay time of Jiangnan orogenic belt, which located in the southeast of Yangtze block, is particularly large, which reflects the complex and intense intra-continental tectonic movements since Neoproterozoic. The crustal anisotropy along the southeast coast can be contributed to the local lithosphere underplating caused by the upwelling of asthenosphere in Cretaceous.