This paper systematically studies the measurement data of horizontal deformation in Shanxi and adjacent regions; further, it gives the evolution of the horizontal deformation field along the Shanxi rift zone. The paper also studies the relationship between seismic activity and stress state in the Shanxi rift zone, including tension subsidence. The paper discusses the method of predicting earthquakes.

In modern seismology, dislocation theory plays an important role in the computation of surface deformation induced by an internal dislocation source. Many researchers have studied quasi-static dislocation theory; however, their works are built on the basic solution of deformation equations given by the classic literature. In this paper, we first review the physical equations of dislocation theory, including the equilibrium equation, constitutive relation, and Poisson’s equation. Then we solve these equations under the non-gravitating, incompressible, and compressible gravitating homogeneous earth model, giving their general solutions including the spheroid and toroid components. The basic solutions under a homogeneous sphere given in this paper can be used to improve understanding and computation of seismic deformations under a layered spherical earth.

After the 2011 Tohoku-Oki earthquake (Mw9.0), near-field GPS data and Ocean GPS data were separately derived for the fault slip model or joint inversion. However, up to now, far-field GPS data are rarely used for inverting the slip pattern. By calculating and comparing the dip and rake angle of four independent source solutions, the paper studies spatial distribution characteristics and rules of the far field earthquake horizontal deformation using GPS data from eastern Asia. Results show that for subduction earthquakes with low dip angles, the horizontal tensile displacement Green Function is the main part of the far-field horizontal displacement. We can also determine the range of effective GPS horizontal displacement data in the inversion. It provides the theoretical basis for joining far-field and near-field GPS observations to invert the fault slip models of the 2011 Tohoku-Oki earthquake (Mw 9.0) and to invert the dislocation Love numbers h and l.

The gravity change rate (GCR), which is derived from repeated gravity data deducted the semi-annual and annual changes of the network of the north China, is used to inverse subsurfacial density change. The results show that the subsurfacial density change trends from negative (Shanxi region), to positive (north China plain), to negative (Bohai bay basin), from west to east. It reveals that the middle and lower crust are in the compressed state caused by the extension of the Shanxi rift and the Bohai bay basin and the upwelling of the lithospheric hot material.

Based on creep meter data from Xianshuihe fault zone, we analyze, by fault kinematics and principal component analysis method, fault activity characteristics and their relationship with the preparation-occurrence of moderate earthquakes around the Xianshuihe fault and great earthquakes in a large-scale area nearby. The results show that: 1) Current kinematic characteristics of Xianshuihe fault are mainly left strike-slip, the dislocation mode is not singlular but turns dextral strike-slip multiple times; 2) Xianshuihe fault zone creep observation shows anomaly variations before the Baiyu MS5.5, Wenchuan MS8.0, Lushan MS7.0 earthquakes, along with the Kangding MS6.3 earthquake, which is a precursor to those earthquakes; further, the amplitude extension beginning at the end of 2001 is affected by the large regional stress field adjustment after the west Kunlun mountain pass MS8.1 earthquake in 14 November, 2001.

Due to the velocity of Love wave is independent of the P wave velocity, the multi-channel analysis of Love wave method has the characteristics of simple dispersion curves, clear energy, less unknown parameters in inversion process, less dependency on the initial model, stable inversion results and high resolution. The results shows that, the near-surface SH wave velocity structure can be obtained by inversion of the love wave in the SH wave reflection seismic data, and the shallow geological structure, fault location and the depth of the breakpoint of the near-surface SH wave velocity structure are in good agreement with the SH wave reflection seismic profile and the drilling data. This technique will provide more explanation for the underground structure basis, and improve the reliability of detection results.

An important problem in long-term prediction and seismic zonation analysis is how to evaluate the potential seismic risk of weakly active faults in weak seismic background. The authors refer to the method that Wen advances to estimate magnitudes of maximum potential earthquakes in sub-areas of the moderately and weakly active faults in eastern Chinese mainland. We build the empirical relationship between the maximum magnitudes Mmax and the at/b values of the sub-areas’ frequency-magnitude relationships. With the empirical relationship, the upper-limits Mu of the Danjiang fault in Laohekou fault area is MS6.0. The average interval recurrence time and the probabilities of destructive earthquake on the fault is evaluated with Possion model.

We process cross-fault data with auxiliary observations such as temperature, precipitation and so on, as observed at Datong and Tangshan seismic stations using particle filter based on residual resampling. Comparing the results with Kalman filters, the feasibility of using particle filter to analyze cross-fault deformation is demonstrated.

In this paper, inter-seismic creep velocity distribution is inversed, based on the InSAR-derived deformation field, using the SDM (steepest descent method) code. Then, the present-day strain state of the fault is discussed based on the inter-seismic creep velocity distribution and the local seismicity. The results show that, firstly, the mid-eastern segment of the Haiyuan fault zone is dominated by left lateral strike slip, and the maximum creep rates are 3.5 mm/a, 2.3 mm/a and 3.4 mm/a on depths of 18－24 km, 18－21 km and 15－21 km, respectively, from east to west direction. Secondly, the locking depth of the Maomaoshan fault is approximately 9 km, showing accumulating stress, and has the potential for strong earthquakes. Thirdly, the Laohushan fault shows aseismic slip in depth, showing less potential with strong earthquakes. Fourthly, the Haiyuan fault shows different movement characteristics on different segments. The eastern and western segments of the Haiyuan fault show obviously afterslip. However, the central segment of the Haiyuan fault shows slight afterslip reaching to 1.5 mm/a, and should be monitored in routine works.

We calculate the value of the effects of fog and hazy weather on GPS zenith tropospheric delay and precise point positioning. Our results show that there is a weak correlation between AQI index and the tropospheric delay when the air quality is continuously good without fog and haze. The most severe fog and haze will affect the zenith tropospheric delay, with effect values from about 40－60 mm. However, in precise point positioning, most of positioning inaccuracy affected by haze can be eliminated by the method of tropospheric delay parameter estimation, in which there is a weak correlation between AQI index and the accuracy of precise point positioning, whether or not there is heavy fog and haze.

In this paper, in order to study the influence of elevation masking angle and GNSS systems integration on PPP precision, we use the data from partial MGEX stations of 10 d are dealt with the PPP method of 24 h respectively. We analyze the number of visible satellites and the positioning precision of single GPS, BDS, GLONASS, double systems integration of GPS/BDS, GPS/GLONASS, GLONASS/BDS, and triple systems integration of GPS/GLONASS/BDS, under different elevation masking angle from 5° to 55°. The results show that the elevation masking angle should be set to under 30° in the single system, under 40° in the double systems, and under 55° in the triple systems. The optimal elevation masking angle of all system integration is from 7°
to 15°. When the elevation masking angle is less than 40°, the highest positioning precision is GPS/GLONASS/BDS and the lowest is BDS. When the elevation masking angle is more than 40°, it mainly depends on BDS to locate, and the positioning precision of all the system combinations is roughly equal. Moreover, as the elevation masking angle increases, the influence of systems integration on the PPP precision is gradually reduced.

In this study, totally eight typical spacecraft are selected, including three types depending on their orbit altitudes, namely low earth orbit, medium earth orbit and high earth orbit, respectively. A numerical integration method is applied for orbit propagation with orbit initial conditions obtained by Two Line Elements. Furthermore, the individual effect of each discussed perturbation force is compared with reference orbit. Consequently, analysis and summaries indicate that remarkable displacement bias is caused by the Earth geopotential gravity. Besides, atmospheric drag is connected with orbit altitude, which is at a very small level for a medium or high orbit. Meanwhile, results show apparent periodic variance of solar radiation pressure corresponding to spacecraft operating period.

This paper has discussed the change of cross-links’ numbers and PDOP values for the GEO,IGSO and MEO in the cases of different schemes by UHF signal and Ka signal aimed at the simulated constellation of BDS. Besides, some different cases of cross-link schemes have been designed. Using these simulated observations 60 days’ auto-navigation has been performed. The influence of the cross-link ranging mode and the cross-link configuration to the precision of auto-navigation has been analyzed. The results indicate that the corss-link ranging mode will not affect the precision of auto-navigation. But the cross-link configuration will influence the precision of auto-navigation in the order of centimeter. Therefore, while designing the inter-satellite cross-link, navigation’s precision, link’s load and construction cost should be considered in order to achieve the best result.

Existing triple-frequency cycle-slip processing algorithms are usually not effective, and the threshold setting may be not reasonable for cycle-slip detection and repair under high ionospheric activity. To solve those problems, the triple-frequency total electron contents rate(TECR) method for whittling ionospheric delay is proposed based on the dual-frequency TECR method. Both the triple-frequency TECR method and triple-frequency code-phase geometry-free and ionospheric-free combination in this algorithm can whittle the influence of ionospheric delay effectively and determine reasonable threshold adaptively. Triple-frequency measured data are used to validate this algorithm, and experimental results showed that this algorithm can whittle ionospheric delay effectively and can realize the detection and repair of cycle-slip dynamically under ionospheric active conditions.

We propose a new method for cycle slip real-time detection and repair using un-differenced dual-frequency GNSS carrier phase observations, based on Melbourne-Wübbena linear combination and Geometry-Free combination. In M-W combination, the combination of weighted according the satellite elevation and moving window averaging is recursively used to calculate the wide-lane ambiguity. Then, the second-order time-difference phase ionospheric residual is used in phase ionospheric residual method. This reduces the influence of ionospheric variations to enable the detection of cycle slips. When the cycle slips are detected, the search method is used to repair cycle slips. The proposed method is tested using static data and dynamic data, the sampling rates are 30 seconds and 1 second recursively. Further, we add some simulated cycle slips in these data, which include big cycle slip and small cycle slip. The results indicate that this method is effective for cycle slip real-time detection and repairing.

The multivariable regression model combined with least squares is proposed to forecast polar motion. The residual error prediction model is constructed by using the PMX residual and PMY residuals, which not only utilizes the correlation information of the PMX residual and the PMY residual, but also uses the correlation information between the PMX residual and the PMY residual. By comparison with the prediction results of LS+AR model, it is proven that the prediction result of LS+MAR model is better than that of LS+AR model, and the superiority of LS+MAR model is also proven. In addition, by comparison with the prediction results of EOP_PCC, it is proven that the LS+MAR model can obtain the prediction results equivalent to the best international prediction accuracy in short-term polar motion prediction.

The decorrelation algorithm can reduce the correlation of the variance-covariance of the ambiguity, decrease the candidate numbers effectively, and further increase the effect of the search. The assessment measures contain condition numbers, decorrelation coefficients and candidate numbers. However, the condition number and decorrelation coefficient can only assess the performance of decorrelation and the candidate number merely assesses search efficiency. None of these can assess the decorrelation algorithm comprehensively. Hence, in this contribution, we adopt time efficiency to assess the decorrelation algorithms. Time efficiency includes decorrelation time efficiency and search time efficiency. Simulation and real GNSS data are used to compare and analyze the three decorrelation algorithms by time efficiency measure. In terms of time efficiency, the results of the experiment show that the integer Gauss algorithm performs best, the pair Cholesky performs slightly worse than Gauss, and LLL-IGS performs worst.

Fast and effective resolution of GNSS carrier phase ambiguity is a crucial precondition for attitude measurement. This paper discusses and analyzes the least square algorithm with a baseline length constraint (CLAMBDA). For practical applications, the general calculation procedure of CLAMBDA method is given. In view of the inadequate searching efficiency in processing high dimensional ambiguity by the CLAMBDA method, an improved CLAMBDA method based on partial ambiguities searching strategy is proposed. The searching efficiency can be improved because the new algorithm reduces the dimension of ambiguity and gets a better searching space by optimizing partial ambiguity. The results of three examples show the new algorithm consumed less time with a high success rate than the original method, and the search efficiency is increased. Meanwhile, the new method is more suitable for real time GNSS attitude measurement.

As for total least squares,it is also common to process different precise of data or different types of data.The weights determined by prior variance are not accurate.And at the same time the condition that there are gross errors in observation data is taken into consideration.For these two problem,the variance component estimation for robust total least squares is proposed.The robust estimation and the Helmert variance component estimation are applied into total least squares.At last,two experiment are carried out to testify.The result of calculation demonstrate that the method proposed in the paper is feasible and effective.

We first construct the relationship between seismic wave velocity and soil physical index using drilling, in-site test and soil test data, as known input information. Then in the same seismic arrangement, rayleigh wave velocity and longitudinal wave velocity can be picked up from the same seismic section, which is divided into velocity layers. This permits calculation of some foundation physical soil properties, such as compactness, uniformity and bearing capacity, based on the relationship.

This paper introduces the main aspects of mobile geomagnetic observation database and mobile deformation observation database, including the contents of the database, the design of tables, the design of various codes, and other important technical concerns. And we also provide the detailed lists of the two databases and their relational graph.

The coordinates and velocities of 260 CORS of CMONOC in the ITRF2008 are determined with the GAMIT/GLOBK and QOCA software. The comparative results of the two software show that, QOCA can deal with the non-linear change of station’s displacement, and improve the calculation precision by means of fitting the annual and semi-annual term, by eliminating common mode error and so on. Compared to GLOBK software, the RMS of fitting residual series acquired with QOCA decline by a factor of 70%, 80% and 70% in the N, E, U direction, respectively.