Shuangxi Zhang

Wuhan University | WHU · Department of Geophysics

On May 21, 2021, the Yangbi MS6.4 Earthquake occurred on Weixi-Qiaohou Fault in Yunnan Province of China, which caused a large number of casualties and property losses. The 2013 MW5.3 earthquake and the 2017 MW4.91 earthquake have also occurred on the same fault. We inversed the focal mechanism of three earthquake sequences by CAP (Cut and Paste) m...

The Gannan region is situated in Ganzhou City, Jiangxi Province, China, and has a complicated geological background. Seasonal droughts significantly jeopardize the water security of the local population. Groundwater is essential to alleviate the region’s water needs. In this research, the groundwater potential (GWP) of the Gannan region was assesse...

We introduce an approach for the direct measurement of the gravitational potential (GP) along the trajectory of a satellite, with a specific focus on Low-Earth Orbit (LEO) satellites. A LEO satellite communicates with several Geosynchronous Equatorial Orbit (GEO) satellites via frequency signal links. The GP difference can be measured in real-time...

The International Association of Geodesy (IAG) aims to establish the International Height Reference System (IHRS) as one of its primary scientific objectives. Central to the realization of the IHRS is global vertical datum unification, which requires the connection of existing local vertical height reference systems (VHS) robustly and consistently....

By harmonically fitting the arrival times of the P‐to‐S converted phases from the Moho, we systematically investigate the crustal anisotropy beneath the Cathaysia Block (CaB) and the surrounding areas in South China for the first time. The measured anisotropy parameters show strong lateral variations with an average splitting time of 0.35 ± 0.12 s....

In 1954, the Yangtze River valley was hit by heavy precipitation anomalies, which caused large casualties and economic losses; however, systematic analyses of the causes are lacking. Adopting the latest national historical precipitation data collected by the China Meteorological Administration (CMA) and global sea surface temperature (SST) records,...

Mianyang City is located in the varied topographic areas of Sichuan Province in southwestern China and is characterized by a complex geological background. This area is prone to disasters and its varied topography is inconvenient for emergency water storage and supply. Groundwater is essential for alleviating the demand for water and post-disaster...

The Qinling–Dabie orogenic belt, which contain the arc-shaped Dabbashan orocline and is the world's largest belt of HP/UHP metamorphic rocks, formed by a long-term complex amalgamation process between the North China Block and the Yangtze Block. To understand the collision processes and tectonic evolution, we constructed a 3-D S-wave velocity model...

In recent years, mode division multiplexing (MDM) which use the few mode fibers(FMF) as transmission link has attracted widespread attention and many MDM systems were demonstrated. However, some drawbacks arising with MDM cannot be ignored, such as mode coupling, differential mode group delay(DMGD) and etc. Fortunately, many of them can be convenie...

The MS8.0 Wenchuan earthquake occurred on May 12th, 2008 on the steeply reverse fault of the Longmen Shan fault zone, Western China. Catastrophic failure and rupture occurred along the listric sliding surface. Several numerical simulations have been performed to reconfigure the dynamic processes of this strong earthquake. However, few scientific st...

Here we provide an alternative approach to determine the Earth's external gravitational potential field based on low-orbit target satellite (TS), geostationary satellites (GS), and microwave signal links between them. By emitting and receiving frequency signals controlled by precise clocks between TS and GS, we can determine the gravitational poten...

The realization of International Height Reference System (IHRS) is one of the major tasks of the International Association of Geodesy (IAG). A main component of the IHRS realization is the global vertical datum unification, which requires the connection of the existing local vertical height reference systems (VHS). However, it is difficult to estim...

Knowledge about the spatial contact relationship between the Yangtze Plate and the eastern Qinling-Dabie orogenic belt can not only provide a scientific basis for the exploration of mineral resources, disaster prevention and earthquake prediction in the region, but also play an important role in reconstructing the geological process of the central...

Knowledge about Rayleigh-wave phase-velocity azimuthal anisotropy can provide important insight into the dynamic processes and complex deformation mechanisms beneath Southeastern (SE) Tibet. In this study, we imaged the azimuthal anisotropy of the Rayleigh-wave phase-velocity in the period range of 10–60 s beneath SE Tibet. The model provides seism...

Yunnan Province is located on the southeastern margin of Tibet and represents an important marker in understanding the tectonic evolution of Tibetan Plateau. In this study, we calculated teleseismic P-wave receiver functions at 49 permanent broadband seismic stations in Yunnan Province and estimated crustal thickness and the bulk crust ratios of P-...

Previous studies have reached consensus that low velocity zones are widespread in the crust beneath Yunnan region. However, the relationships between the low velocity zones and large faults, earthquake distribution are less investigated by available studies. By analyzing the seismic ambient noise recorded by Yunnan Seismic Networks and Tengchong vo...

The Tengchong volcanic area is located in the southeastern margin of the collision zone between the Indian and Eurasian Plates. It is one of the youngest intraplate volcano groups in mainland China. Imaging the S-wave velocity structure of the crustal and uppermost mantle beneath the Tengchong volcanic area is an important means of improving our un...

Inversion of receiver functions is commonly used to recover the S-wave velocity structure beneath seismic stations. Traditional approaches are based on deconvolved waveforms, where the horizontal component of P-wave seismograms is deconvolved by the vertical component. Deconvolution of noisy seismograms is a numerically unstable process that needs...

The upper crustal anisotropy of Yunnan area, SE margin of Tibetan Plateau, is investigated by measuring the shear wave splitting of local earthquakes. The mean value of the measured delay times is 0.054 s and far less than that from Pms splitting analysis, indicating that the crustal anisotropy is contributed mostly from mid-lower crust. The fast p...

This paper presents a comprehensive area expansion prediction index method to apply GNSS for short-impending prediction of earthquakes. Based on continuous GNSS observation data from Yunnan Province, a displacement field was detected after data cycle-slip repair using precision data processing software and geophysical field effect model correction....

The general relativity theory provides a potential way to directly determine the gravitational potential (GP) difference by comparing the running rate or vibration frequencies of two optical-atomic clocks located at two stations. Recently we proposed an approach referred to as satellite frequency signal transmission based on the Doppler canceling t...

During seismic wave propagation on a free surface, a strong material contrast boundary develops in response to interference by P- and S- waves to create a surfacewave phenomenon. To accurately determine the effects of this interface on surface-wave propagation, the boundary conditions must be accurately modeled. In this paper, we present a numerica...

The near surface spatiotemporal pore pressure fluctuations in a porous half space induced by seismic surface–wave perturbations in different poroelastic regimes are analytically compared. The results for the pore pressure in the space–time domain are derived by inverse transforms of the fundamental solutions of dynamic poroelasticity in the frequen...

Spatiotemporal wave–induced radiation pattern in a semi–infinite fluid filled porous medium to an impulsive transverse loading is investigated under imperfect surface hydraulic contacts. A surface stiffness parameter represents this fluid flow impedance cross the surface. It affects various wave mode radiations dependent on azimuth and depth. In th...

The SE margin of the Tibetan Plateau is an important area to develop a better understanding of the plateau uplift and the Indian-Eurasian continental collision dynamics. Previous studies have reported widespread low-velocity anomalies beneath this region, particularly in the Tengchong volcanic field (TCVF). However, the spatial distribution and dyn...

In this study, we propose an approach for determining the geopotential difference using highfrequency- stability microwave links between satellite and ground station based on Doppler cancellation system. Suppose a satellite and a ground station are equipped with precise opticalatomic clocks (OACs) and oscillators. The ground oscillator emits a sign...

The plant-specific sucrose nonfermenting 1-related protein kinase 2 (SnRK2) family is considered an important regulator of plant responses to abiotic stresses such as drought, cold, salinity, and nutrition deficiency. However, little information is available on how SnRK2s regulate sulfur deprivation responses in Arabidopsis. Large-scale production...

High frequency surface wave method based on seismic wave propagation in single-phase media has been widely applied for acquiring near surface shear wave velocity in several fields. However, the near surface earth media, consolidated and unconsolidated, for the general hydrogeological conditions, bear plenty of pores. Fluid in pores affects the surf...

The present study aims to reveal the recovering period of the postseismic fluid pressure in fault zone, offering an insight into earthquake recurrence. Numerical modeling is performed based on a 2D simple layered fault-valve model to simulate the fluid activities within the earthquake fault. In order to demonstrate the features of postseismic fluid...

Lushan Earthquake (~M w 6.6) occurred in Sichuan Province of China on 20 April 2013, was the largest earthquake in Longmenshan fault belt since 2008 Wenchuan Earthquake. To better understand its rupture pattern, we focused on the influences of fault parameters on fault slips and performed fault slip inversion using Akaike’s Bayesian Information Cri...

In this paper, we analyze characteristics of magnetic anomalies calculated from NGDC720 geomagnetic model in the Philippine Sea plate and then decompose magnetic anomalies into the shallow and the deep components. Further, we interpret the causes of magnetic anomalies in the study area. Magnetic anomalies in the Philippine Sea plate not only show t...

The present study calculated the thermal structure, the distribution of buoyancy, and P-wave velocity anomalies in Japan Trench subduction zone using finite difference method, and predicted the range of metastable olivine according to whole and layered mantle convection models. We analyzed the influences of multiple coefficients, such as thermal co...

Three-dimensional transient responses of porous media under moving surface impulses of finite frequency components are theoretically studied. We discuss three free-surface stiffness conditions, such as fully permeable—‘open pore’, fully impermeable—‘closed pore’, and partially permeable boundaries, that are not explicitly discussed before. The tran...

Wave-induced flow is observed as the dominated factor for P wave propagation at seismic frequencies. This mechanism has a mesoscopic scale nature. The inhomogeneous unsaturated patches are regarded larger than the pore size, but smaller than the wavelength. Surface wave, e.g., Rayleigh wave, which propagates along the free surface, generated by the...

The hi-energy bands in the dispersion image are usually interpreted as the true dispersion phase velocities. However, the multiple dispersion modes of Rayleigh wave in layered media stack in space, producing the effective dispersion curve and the pseudo multimode dispersion curves in dispersion image. The effective dispersion curve has the maximum...

Rayleigh wave dispersion signals are significant to underground investigation. Traditionally, uniformed trace spacing is employed in surface wave surveys. In some cases, however, uneven trace spacing is often encountered because of the limitations of the site condition. In order to study the influence of uneven trace spacing on the dispersion data...

Rayleigh wave dispersion can be induced in an anisotropic medium or a layered isotropic medium. For a layered azimuthally anisotropic structure, traditional wave equation of layered structure can be modified to describe the dispersion behavior of Rayleigh waves. Numerical stimulation results show that for layered azimuthal anisotropy both the dispe...

The accuracy and resolution of surface wave dispersion results depend on the parameters used for acquiring data in the field. The optimized field parameters for acquiring multichannel analysis of surface wave (MASW) dispersion images can be determined if preliminary information on the phase velocity range and interface depth is available. In a case...

Rayleigh wave dispersion data usually appear in the form of multimodal spectra for a layered model structure. The number of dispersion modal curves depends on the number of layers in the model. The measured dispersion velocities from the frequency–wavenumber (F–K) space, however, may not represent the true phase velocities of the fundamental-mode d...

Surface wave dispersion data obtained in field surveys are inherently incomplete. Poorly constrained dispersion curves and inclusion of data from higher-mode dispersion curves can be shown to produce erroneous inversion results. The present study evaluates the effects of cross-mode data mixing, and limited data and frequency range on inversion mode...

Summary Surface wave analysis is sometimes used in engineering investigations to obtain ground stiffness profiles by inversed modeling of dispersion velocities. Since dispersion data may be polarized due to material anisotropy, a thorough understanding of the dispersion property is necessary for the accurate reconstruction of inversion models. Base...

An integrated geophysical survey which combines vertical seismic profile method, shallow reflection seismic method, electric sounding, soil temperature measurement and radioactive gas measurement was used to investigate Zhaoshuling landslide in the new site of Badong County and to assess the stability of the landslide. By rational use of these meth...