Tanaka proposes spherical dislocation theories in a spherically symmetric, self-gravitating visco-elastic earth model. Gao presents user-friendly software that utilizes Tanaka’s theory, which can be used to calculate the post-seismic deformations for 30 time points after the event. Based on the work of Gao, we introduce an updated code to compute post-seismic deformations, including geoid and gravity changes caused by an arbitrary seismic source at any position, for an arbitrary time that passes after an event. The code consists of three parts. The first part is 32 set of the numerical frames of the dislocation Green function (DGF). Each frame contains a set of two-dimensional discrete numerical frames of DGFs on a symmetric earth model, according to a time point after the event. The second part is an interpolation program. Based on the above 32 sets of the numerical frame of DGF, the program can be used to calculate a set of DGF, according to an arbitrary time point after the event, as well as the mantle viscosity around the epicenter. The third part is an integration function, which performs bi-quadratic spline interpolation operations on the calculated frame of DGFs. The inputs of the integration function are the information about the seismic fault models and the observation points. After the user prepares the inputs in a file with a given format, the code will automatically compute the post-seismic deformations. Then, we calculate the co-seismic displacements caused by the 2011 Tohoku-Oki MW9.0 earthquake using the visco-elastic and full-elastic spherical dislocation theory, respectively. The two sets of results agree with each other very well. This verifies the correction of our new codes. Finally, we discuss several issues that require attention when using the code, which should be helpful for users.

The research results show that dynamic background of the Ordos block is the Tibetan plateau compression from an East-West direction. The seismic activity of the Ordos block northern margin since 1970 shows that the moderate seismicity is characterized by episodic activities; moderate earthquakes of Ordos block experienced 4 curtains from 1970 to 2015, strong earthquakes of the northwestern and northeastern margins of the Ordos block has migrating characteristics, a total of 4 curtains since 1970, (before the magnitude 6 earthquake in the northern margin of the block). The moderate earthquake of the entire block has been quiet a long time according to the statistical results of earthquake examples, while moderate seismic is in a long quiet stage in Yinshan seismic zone since March 2005. The curtain activity and migrating characteristics, as well as the time calm characteristics, can be used as a prediction index for strong earthquakes in the region.

The focal mechanism solutions of 1 700 ML ≥2.5 small to moderate earthquakes which occurred in the circum-Ordos block and its adjacent areas from Jan. 1, 2008 to June 21, 2014 are obtained using the HASH method. The stress tensors and the orientations of the maximum horizontal stress of the circum-Ordos block are determined by the MATLAB package for spatial and temporal stress inversion (MSATSI) using 1°×1° grids, with the damping parameter 1.2 at the 95% confidence level. The characteristics of the spatial distribution of the focal mechanisms are investigated and their tectonodynamic background is discussed. Main conclusions are drawn as follows. In the rift zone of Yinchuan-Jilantai, Hetao, Shanxi and Weihe, which are located around Ordos block, the main types of the composite focal mechanism are strike-slip and normal types, which reflect the Ordos block suffering shear and extension stress field. There are different stress regimes around Ordos. Yinchuan-Jilantai, which is located northwest of Ordos, is a normal stress state which matches well with the regional geodynamic mechanisms, but the nearly north-south active fault presents strike-slip regime in the southern part of the northwestern segment which is forced to right-lateral strike-slip shearing from the NE. Three types of the composite focal mechanism are thrust-strike-slip and normal types in the Haiyuan-Liupanshan fault zone located on the SW boundary of Ordos block, which are under the joint action of the NW and NE compressional stress field. The maximum horizontal principal stress orientations are dominanted by NE and NW orientation. That may derive from the NE-directional pushing force from the Qinghai-Tibetan plateau and NW-SE directional extension caused by the uplifting of the deep substance of the Qinghai-Tibetan plateau. The maximum horizontal principal stress orientation seems to rotate slightly anticlockwise in the Shanxi rift, their stress pattern: EW-NE-NEE from south to north, and most of them parallel to the main fault’s strike, which controls the boundary of the Shanxi rift belt. Datong basin, which is different from the entire grabens extension, is shear. These phenomena are related not only to the special geographical environment and tectonic conditions, but also to the volcano underground Datong basin. These are relatively independent of the local stress fields in transverse uplifts between basins, in which the focal mechanisms are dominated by reverse and uncertain types. The stress regime in the northern boundary of the circum-Ordos block is in a NE direction normal type stress state. There are two maximum horizontal principal stress orientations in southern area of Ordos’s block: Qinling tectonic belt is NW direction extension stress state, and Weihe graben is in EW direction extension stress state.

Based on precise leveling observation data, the vertical motion velocity field of western Sichuan-Yunnan province is obtained using vertical velocity at GNSS point as an a priori value to constrain adjustment and vertical velocity of GNSS continuous station less than 10 km away from level line to inspect. Residual statistical analysis at GNSS test point and benchmark suggest that vertical velocity precision at the benchmark is superior to 0.89 mm/a and error distribution is relatively uniform. The vertical motion velocity field of the Sichuan-Yunnan region indicates that western Sichuan province is in the stage of rapid differential uplift, wherein the uplifting rate in Gongga mountain region located to the southeast of Xianshui river is the fastest (5~6 mm/a), that vertical motion in Sichuan basin is not obvious, wherein the rate is between 0~1 mm/a,and that sinking occurred in southwest Yunnan at the rate of 0~2 mm/a, which is consistent with the observations by GNSS. In addition,the tension characteristics of major faults inwestern Sichuan-Yunan province are analyzed through level velocity profile.

First, based on the three-disclination model, this paper simulates the surface deformation of the single fault, which has a dip angle of 60° under the different angle and direction of rotation,in order to analyze the influence of fault rotation on the size of the surface deformation field and the characteristics of spatial distribution. Second, based on the disclination-dislocation model, the surface deformation caused by fault sliding and rotation of the Xianshuihe fault zone is simulated by numerical methods and is compared with the GPS data of 2009-2015, which eliminates the overall displacement. Result show: 1) the angle of rotation is proportional to the surface deformation caused by the disclination of fault, but the displacement field direction remains the same; when the direction of rotation changes, so does the surface displacement field, but the size remains the same, with greater impact on the displacement field near the fault; 2) based on the disclination-dislocation model, the simulated results and GPS measurements of the Xianshuihe fault zone show good consistency;3) there are some characteristics of rotation in Xianshuihe fault zone, with obvious differences with every block, and a certain transformation tectonic style.

Some good observation quality strain data are selected to calculate and count strain components: changes of maximum principal strain, minimum principal strain, principal direction and maximum shear strain from May 15, 2016 to 2017, including data from Liaoning, Hebei, Shanxi, Shandong, Jiangsu, and Hubei provinces. Relevant regional short-term seismic activities are also analyzed with corresponding regional earthquakes measuring 3 or above.

Aim at the problem of fewness data and update slowly in velocity field, this paper studied the methods of data obtain and analysis for velocity field build. Using observation data from crustal movement observation network of China surveyed in 2011-2015. Both high precise coordinate and velocity of the 260 stations have been calculated with GAMIT/GLOBK and GMT software. Building the 1°×1° grid model of velocity field in mainland China using Kringing method based on the 260 stations velocity. And then estimating the grid model using the velocity of seven IGS stations in China from IERS and 2000 region stations from CMONOC. The result can be concluded that this grid model have higher pricese and reliability. The result in this paper have a great significant for engineering.

According to the modeling problem of non-equidistant subsidence data sequence, the application of three kinds of non-equidistant GM (1, 1) models in subsidence prediction is discussed. The analysis results show that the weighted non-equidistant GM (1, 1) model is not appropriate for the subsidence data with approximate exponential trend, and the grey linear weighted non-equidistant GM (1, 1) model is not a really equidistant model. The prediction formula of the grey linear weighted non-equidistant GM (1, 1) model has nothing to do with the time, and cannot be used for subsidence prediction. The fitting function of the non-equidistant GM (1, 1) model established by the author is equivalent to that of grey linear regression combined model, and can be used on the subsidence data with approximate exponential trend. Finally, the effectiveness of the three kinds of non-equidistant GM (1, 1) model are compared by example analysis and this validates the correctness of the above viewpoints.

Through defect analysis on traditional GM(1,1) and the mechanism description of improved base on the weight of PGM(1,1), we consider that if the same parameters are taken in GM(1,1) when constructing background values, then the prediction error of the model cannot be sufficiently reduced. Different parameters are applied at different times to improve the GM(1,1) background value sequence formula. This kind of background value construction method and grey element N are applied to the GM(1,1) to build a new albino equation. On the basis of the establishment of the new albino equation, the modified initial value through the Runge-Kutta method is applied to calculate the accumulated value of the simulation sequence. To resolve the introduction of many parameters, the particle swarm optimization algorithm is used to find optimal parameters which satisfy the relative error, so the PSD-GM model based on the particle swarm optimization algorithm and the weighted grey combination is established. The application of an engineering example shows that fitting precision of the new model is high, the predictive effect is good, and the predictive accuracy of the new model is improved significantly compared with the other two models.

Precipitable water vapor is one of the key factors influencing weather and climate change; change in water vapor is closely related to temperature and atmospheric pressure. In this paper, we conduct a correlation analysis of GPS water vapor and meteorological factors by using GAMIT software solver the value of PWV for Beijing combined with meteorological data. Firstly,we used GAMIT software solver on the value of PWV for Beijing continuous observation network data from June 1,2009 to April 30,2012, in conjunction with atmospheric pressure data, to acquire station PWV sequence. Then we used wavelet transform method to break down and reconstruct the data for GPS PWV, temperature and atmospheric pressure and analyzed the correlation of new data. There is a positive correlation between the trend of GPS PWV sequence and temperature, and a significantly negatively correlation with atmospheric pressure. The PWV and atmospheric pressure have half-cycle and annual change; both appear in an obvious negative correlation. Temperature cycling for years, the best correlation of water vapor and temperature is in d13 reconstruction. There are significant positive correlation properties.

Orbital state vectors are important parameters that play crucial roles in the processing of InSAR, from the original offset of coarse registration to the accurate generation of the ultimate DEM or deformation measurements. Errors in the baseline are caused by errors in the orbital state vectors, which present as phase errors in the interferogram. We map the coseimic deformation of the 2011 Tohoku earthquake with data from four ascending ALOS/PALSAR tracks and GPS coseimic displacements that cover most of northeastern Japan. The quadratic polynomial approximation is proposed to eliminate orbital errors from the interferogram, and we analyze the effects of incidence angle. The precision of corrected coseimic deformation measured by InSAR is verified by analyzing the residual deformation in the interferogram.

No singularity orbital elements combination with coordinate rotation is applied to 18-parameter ephemeris fitting model for GEO satellites in this article, which synchronously solve the singularity problem caused by small eccentricity and small inclination. Based on one year data of five Beidou GEO satellites in orbit, the fitting accuracy and stability are analyzed, and during the eclipse the fitting accuracy is quantitatively analyzed. Finally aiming at parameter’s exceeding limitation, the range of variation of parameters between 55° and 5° rotation with X axis is compared. The results show that in 2-4 h fitting arc the maximum fitting error for five GEO satellites is of only 3 cm, and the number of iterations is up to 5 times. The longer the fitting arc the worse the accuracy, and the longer the fitting arc the fewer iterations. During the eclipse, the fitting accuracy gets worse. The range of variation of parameters of 55° rotation with X axis is reduced by one order of magnitude compared with 5° rotation with X axis. There are no parameters exceeding limitation in the overall year.

The coefficient matrix is the functions of some independent variables in the polynomial fitting model. According to the solution of the partial errors-in-variables(Partial EIV) model, the random elements that   are the functions of independent variables of the coefficient matrix are extracted. Considering the quadratic terms of the Taylor expansion, the cofactor matrix,which is the functions of independent variables, is obtained by the law of covariance propagation. The experiments show that the results obtained by the method of this paper are similar to those obtained by the method of existed non-linear total least squares method when the elements of coefficient matrix are no more individual independent variables. This provides a method of structuring the weight matrix of random vectors.

The high precision and sampling acquisition rate observing system of broadband digital seismometer shows that broadband digital signal contains rich crustal movement and damage information. However, the information remains to be further excavated. The broadband digital data of WMQ, LSA, ENH, KMI and XAN stations are analyzed based on fatigue damage theory, for a few days before the November 14, 2001 earthquake at western Kunlunshan pass. The results show that the relative stress of the stations increases significantly in the days before the earthquake.

This paper introduces the first phase of the project of the construction of the national infrastructure absolute gravity observation modern surveying benchmark system in 2013-2014 by A10/028 and FG5/214 gravimeters. The measured results are analyzed, showing that the absolute gravity observation precision and difference is 5 μGal, meeting the requirements of high precision gravity base construction. The results also show that A10/028 is adaptable to field observations of gravity changes, that FG5/214 signal acquisition has advantages, and that using two sets of absolute gravimeter data in the same periodim proves the accuracy of observation results.

Based on the repeatability and low signal-noise ratio of active source events, we propose an auto detection method of active source events using template matching techniques. A continuous waveform (25 200 seconds) of CKT(SHZ) is processed by a program using template matching and correlation calculating techniques. 13 air-gun earthquake events are detected and the trigger times are picked up. The results indicate a 100% accuracy with no misdetections. The method can be used for auto data handling processes for active source or seismic arrays that produce huge amounts of waveform.

We propose the correlation method for estimating the magnetization direction of magnetic bodies under the influence of remanent magnetization. First, we determine the parameter range of magnetic inclination and declination, obtaining a serious of values of the magnetization direction at equal intervals. Then, the measured magnetic total field anomalies are transformed into the reduced-to-the-pole data according to the different magnetization directions. Finally, the cross-correlation between the reduced-to-the-pole data and the normalized source strength data is solved. The theoretical magnetic total maximum correlation coefficient is regarded as the estimated total magnetization direction. Simulation and experimental results show that: this method can effectively estimate the magnetization direction of the magnetic bodies, especially when the magnetic total field anomalies are approximate equiaxial.

This paper uses the maximum entropy method (MEM) to analyze geo-electric data of Changli, Xingji, Xinle, Yangyuan, Feixiang, Dabaishe stations in Hebei province, combined with geomagnetism data, to analyze the spectral features of components of the telluric electric field data. Results show that: the telluric electric field period is mainly 12 h semidiurnal wave components, with 24, 8 h periodic components significantly in Hebei province; during magnetic-storms, the spectrum value is higher than in quiet diurnal variation; telluric electric field of diurnal changes of periodic components come from changing current system of outer space. The results reveal the background spectral components of geo-electric field observation in Hebei province, and provide reference for the application of telluric electric data in earthquake prediction.

This article briefly introduces the most common vibration isolation systems in the absolute gravimeter,comparing several kinds of mechanical vibration isolation systems with the FG5-112 absolute gravimeter under the same conditions. We evaluate the vibration isolation performance of these systems, which gives guidance in designing high performance vibration isolation systems independently in the future.