地震可能引起地下水物理和化学性质的改变。2016年4月7日山西原平4.2级地震震后31 h，在距震中约12 km的原平市崞阳镇下韩村出现井水冒泡现象，井水冒泡时间在每天10:00～23:00，具有一定周期性。为了研究该现象与地震的关系及其原因，使用井下电视成像仪探测了井管情况和冒泡位置，测试分析了井水中逸出气体成分、化学组分和氢氧稳定同位素组成特征。结果表明，冒泡井的地下水补给源主要来自大气降水，采用定性和定量相结合的方法分析井水冒泡异常，有助于识别地下水异常的构造与非构造影响因素，对今后地下水宏观异常核实具有指导作用。

The quaternion has been widely used in three dimensional space datum transformation, but its theoretical basis is not very clear.  This paper studies some basic properties of the quaternion theory, and it proves that coordinate rotation transformation is equivalent to the orthogonal transformation of quaternion.  Using the definition of basic quaternions, it establishes that all quaternions applied to coordinate rotational transformation are made by several basic quaternion’s Glassman product.  At the same time, the theoretical relationship between quaternions and coordinate rotation matrix are given.

We study the prediction performance of several frequently-used methods used for navigation satellite clock bias prediction, including the quadratic polynomial model, the spectral analysis model, the grey model (GM (1,1)), the ARIMA model and the Kalman filtering model. By using the precise SCB data of GPS, the prediction tests are carried out to analyze their prediction results. The advantages and disadvantages of these methods are then compared. In addition, the prediction characters of six-type GPS sapceborne clocks in orbit are roughly analyzed.

Abstract: This paper aims at exploring the algorithm of g7 by processing the data from FG5 and A10 absolute gravimeters. When the observation equation and algorithm offered by the the software user manual is used to process the A10 data, the difference between the results of the designed program and the g7 software is less than 3 μGal. However, for the FG5 data, the difference is too large to accept. After correcting the observation equation and time observations, the latter is within －0.1—0.1 μGal. We believe that the models and algorithms mentioned in this paper are same as those used in the g7 software.

This paper introduces an new “spherical model” formula of gravity’s middle layer correction algorithm, which considers the influence of earth curvature.  We then, through different calculation examples, analyze error comparisons between the two algorithms.  Results show that the magnitude of the maximum errors can reach 0.4 mGal, so this paper suggests that it is necessary to use the new gravity’s middle layer correction algorithm in surface gravity prospecting work.

The Mw7.8 Nepal earthquake occurred on April 25, 2015, with several strong aftershocks that caused effects in the Tibetan areas of China. In order to predict the strong aftershocks of Nepal earthquake, an improved “waiting time” model using weighted least square fitting is proposed based on the theoretic residual analysis. The new model is then applied to the Nepal earthquake sequences to better predict outcomes. Results indicate that the proposed method effectively reduces model prediction errors as well as the confidence interval. Also the prediction errors are zoomed by ln10·Δt (Δt is the waiting time of the last aftershock) from model axis to real time axis. For this reason, the aftershock samples should be chosen within 3 days of the main earthquake.

We use two methodsto get the ocean floor deformation data caused by the 2011 Tohoku-Oki earthquake. Then the gravity effects due to the redistribution of ocean floor mass can be calculated through Fourier transformation and Fourier inverse transformation. These gravity effects are analyzed and compared to the gravity data observed by GRACE satellite. The results show that these gravity effects are notable, and should be of concern during extracting coseismic gravity changes.

Determining accurate regional geoid with Stokes theory can be affected by gravity data errors, such as resolution of gravity, precision of mean gravity and integral radius. In order to solve this problem, the magnitude of truncation errors of geoids in different terrain areas, which are caused by gravity resolution and integral radius, are given based on the analysis of characteristics of the gravity frequency spectrum. Also, the effect of error of mean gravity anomalies on geoid construction is calculated. Therefore, the results put forward in this paper contain great theoretical value for centimeter geiod calculation in different terrain areas.

Multi-step prediction, a new algorithm based on ensemble empirical mode decomposition (EEMD) for dam deformation prediction, is presented.  Firstly, starting from the time-frequency analysis, with the use of a collection of empirical mode decomposition, deformation time series are broken down into characteristic components of different frequencies.  Secondly, run-determination act is used to reconstruct volatility components similar to high, medium and low ones.  This is effective in centralizing model predictive feature information and reducing the difficulty.  Finally, multi-step prediction model of the three is established separately and the predictive values are overlayed as the final prediction result.  The calculation result is analyzed and compared with the AR model, BP neural network and SVM.  At the same time, different prediction verification instructions are established to prove our algorithm.  The results show that the prediction accuracy of EEMD is higher, it can guarantee better prediction of dam deformation in volatile periods| it is feasible to apply to dam deformation prediction.

采用SZW-1A型水温仪完成温度梯度测量，从房县三海村井观测记录中分析该井的动态特征，测量得出：①三海村井平均梯度为2362 7 ℃/hm，梯度分布较不均匀，50～60 m处梯度极大值为7548 ℃/hm，梯度下降井下90~110 m处，负梯度最低值为－4051 ℃/hm，至井底1115 m处又恢复为正温度梯度。②2017年9~10月强降雨，三海村井上半部分受低温循环水作用，使水温4号测点、水位观测趋势转折幅度减小，而在井底105~110 m最小正梯度处，水温传感器记录较为稳定，随降雨与裂隙横向渗透，铁矿物质的水化学作用致使井水温2号测点小幅升高。③水温传感器的放置位置应对温度梯度、围岩特性、观测稳定性综合考虑。

Velocity results from published papers, which are in different reference frame, are transferred into a self-consistent frame based on common GPS velocities of each result.  We investigate the interseismic coupling of the rupture fault before the Nepal earthquake based on interseismic GPS velocities along a profile in N15°E direction, which runs across the rupture region of the 2015 Mw7.9 Nepal earthquake.  We model the creeping fault as a planar semi-space dislocation embedded in elastic half-space, and invert the horizontal velocities to infer the preferred locking depth and slip rate.  The preferred model indicates that interseismic deformation is induced by a fault dipping at 10°, buried at a depth of 22.5 km, with a slip rate of 19.0 mm/a.  Then, near field coseismic displacements measured from GPS observations are presented.  The largest horizontal displacement of 1.89 m was recorded at KKN4 in Nepal.  Coseismic offset of 54 cm was measured in southern Tibetan plateau, which is the largest value measured in mainland China.  The displacements decrease rapidly to less than 5.0 mm at GPS stations 400 km away from the epicenter.  GPS derived coseismic displacements along the N15°E profile show that the offset near the fault trace is not the largest offset measured by GPS, indicating that the shallow part of the fault did not rupture during the Nepal earthquake.  The horizontal coseismic offset profile can be modeled well using a buried rectangular dislocation model.  Therefore, we infer the rupture fault of the Nepal earthquake may be the main Himalaya thrust (MHT), and the shallow parts did not rupture during the shake.

Earthquake models are restricted to the academic and scientific level| further, they evolve over time.  We researched the history of earthquake model evolution: models that consider only the hypocenter region (fault zone)→models that consider hypocenter region together with surrounding tectonics→models that consider upper crust brittle layer and deep crust ductile layers coupling with upper mantle→models that consider the earthquake as an activity of present continental deformation dynamic system’s self-organization evolution process.  The evolutionary trend is from hypocenter to dynamic system over a hundred years.  Its characteristics are: time-space domain expands, dimension rises of the models| from reductionism mechanism to holism| from classical mechanics to complex system theory and nonlinear dynamics| new models contain and surpass old models, and are better approaching nature.  Benefitting from the unprecedented achievements of seismic geodesy, strong correlativity and interdisciplinary methods, new earthquake models are developing.

In order to build a navigable high-precision gravity reference map efficiently, it is indispensable to improve the precision of the interpolation algorithm, and take its optimization into account.  In view of the difficulty of optimizing an efficient interpolation algorithm for gravity reference maps in the various interpolation algorithms, a interpolation optimization algorithm for gravity reference maps in local anomaly fields is put forward.  This algorithm realizes preliminary optimizing of the different algorithms by studying long-term data interpolation, determining the weight by means of an analytic hierarchy process, and defining quantitative coefficients of the optimization algorithm (named optimizing degrees).  The experimental results show that the optimization algorithm is operational and that the time to interpolate a gravity reference map is reduced in special conditions.

The vertical deformation rates in Tianjin area was calculated from standard data of repetition measurement during 20052012,and the interference of settlement of each line was excluded to enhance the information of crustal movement. The recent motion of block and recent activity of fault were studied based on the results in the area. The results showed that the overall trend of vertical deformation were to rise at northern part and to fall at southern part in Tianjin. There were differences in movement of the blocks. Some tilted, some overall rose, and some pleated. The recent activity rate of main faults in Tianjin Area was in 0.251.16 mm/a.Most of faults activity were inverse, and a few normal.

This paper introduces the time series prediction model of ionospheric VTEC improved by wavelet decomposition. The VTEC grid data released by IGS in 2013 are taken as experimental data to model point by point. Firstly, the VTEC series of 5 112 grid points are decomposed using db4 separately, then predicted using time series analysis, and finally reconstructed to predict the VTEC.  The forecast bias and RMSE of the common prediction method and the improved method are compared.  The result shows that the precision and the proportion of high accuracy using the improved method are better than the common prediction method. The improved method achieves the aim of raising accuracy.

In this paper, the vertical component seismic record data of 15 near-field stations of the Minxian-Zhangxian MS6.6 earthquake are used to analyze the main shock. The average centroid frequency is calculated, and its geographical distribution is given. The results show that the high frequency distribution is in southwestern sides of the Lintan-Tanchang fault, not along the Lintan-Tanchang fault; the elliptical long axis parallels to the fault strike. That is to say, the thrust block of this earthquake is between the southwest side of Lintan-Tanchang fault and the other fault. The geographical distribution of the highest frequency of the spectrum is in agreement with the macroscopic epicenter. It can be considered that the highest frequency region of the spectral centroid is the most serious area of earthquake disaster.

The principle, development status and application of atomic clocks were introduced and their main functions were compared with each other.

The combination of the phase observations between different frequencies is presented, using the Galileo four frequency as an example| and the general form of combination observation in the unit of cycles and meters is given. The ionospheric error, wavelength and the observation noise is analysized in detail. With the integer ambiguity as a prerequisite, some useful linear combination as long wavelength, weak ionospheric delay and weak observation noise is researched. Finally, depending on the combination principle, programming to calculate combination coefficients of different navigation system and several typical combination coefficients are given.

In GPS regional network coordinate time series, common mode errors (CME) are widespread. In order to extract CME, a sub-region is divided to get them superimposed and filtered. However, there is no principle to rely on for dividing sub-regions. According to the CME mentioned above, regarding three stations in southern California as centers, we divide the space into nine different spaces within different scales, carrying out the PCA space filtering method, to get the CME in each space scale. After analyzing and comparing the CME in each space scale, we can get the spatial response characteristics in CME, which provides a principle for the dividing sub-regions in the scale field.

Magnetic declination is the angle between magnetic north and true north, the angle will change with the variation of latitude, longitude and height. The relation between magnetic meridian azimuth and true azimuth is discussed, and the calculation formula of magnetic declination and geomagentic inclination are deduced when the latitude,longitude and height are known.At the same time,the magnetic declination and geomagentic inclination in China are calculated, and their variation rules with the variation of latitude, longitude and height are analyzed.

How to choose the relative weight ratio λ is an important problem that deserves to be studied in inversion models when using more than two physical measurements, including the geodetic displacements to implement the joint inversion. The idea of computing the  λ  with it and other inversion parameters as the parameters to be inverted is put forward, and the inversion model is derived in detail.  Through simulated data and the solution, the effectiveness and feasibility of the method above is proven.

In order to improve the accuracy of IGS ultra-rapid predicted products(IGU-P), in response to the data characteristic of ultra-rapid ephemeris composed of both determined and random items, a new prediction algorithm is proposed. This proposed algorithm is based on a polynomial model, which models random items with adding-weight one-rank local-region method of chaos. The results from the calculating examples show that the accuracy of adding-weight one-rank local-region method of chaos is superior to that of the IGU-P.

Using the FG5 absolute gravimeter, absolute gravity values are determined at three base gravity sites in Lushan and one datum site in Jiujiang seismic station to determine the Lushan calibration baseline.Further, twenty-five sites are determined using seven CG-5 relative gravimeters with two return measurements. The results show that the accuracy of gravity values at all of the base sites is better than  ±5.0 μGal.The application of FG5 absolute gravimeter along with several relative gravimeters to construct short calibration baselines is a new and modern approach which has scientific significance as well as economic value.

The combination of EMD and wavelet analysis is used to detect the period of VTEC. The possible period of ionospheric activity is detected by analyzing the IMFs under multi-scale with wavelet analysis. The probability can be increased with this new method. The VTEC series at different latitudes released by IGS is used as an example. The feasibility and validity of the method promoted in this paper is proven. The possibility of 6 d, 24 d and others is discovered and a new approach is proposed for period detection of VTEC.

The reason why the crystal oscillator does not work is analyzed and the importance of crystal capacitance is emphasized. The corresponding solution methods are presented.

This paper addresses the reason why a geocentric coordinate system is adopted for us, and expounds the definition and realization of the China Geodetic Coordinate System 2000（CGCS2000） and compares it with WGS84. The CGCS2000 is a geocentric system adopting the GRS80 ellipsoid, and is realized by coordinates and velocities at epoch 2000.0 of the points of the national GPS geodetic network 2000. It is consistent with ITRF and compatible with WGS84.

Using wavelet analysis method to process aeromagnetic data in the Qinghai-Tibet plateau, aeromagnetic anomaly maps with different scales are obtained. Results from the first order wavelet analysis reveals the structure feature of shallow crust. In the sutureⅠ and sutureⅡ regions, there exist several clear arcuate structures with NWW-striking, as shown by alternatively positive and negative magnetic anomaly belts. There exists a negative magnetic anomaly belt with near EW-striking in suture Ⅳ near Golmud. The results from the third order wavelet analysis show the structure feature of deep crust. The main feature of deep structure in this region is represented by an obvious negative magnetic anomaly belt with near NS-striking between 87°N and 93°N. The Nepal M8.1 earthquake and its three strong aftershocks with magnitude 7 all occurred near the southern end of this magnetic anomaly belt, where the EW strike Himalaya tectonic belt intersects with the NS-striking negative magnetic anomaly belt. In general, the aeromagnetic data in Qinghai-Tibet plateau shows that, the main feature of shallow structures is near EW-striking, but the deeper structure is SN-striking. It implies that the intersection of the complex overpass structures is the tectonic background of the Nepal M8.1 earthquake.

Earthquake cycles based on the site of the 2011 MW9.0 earthquake in Tohoku, Japan was simulated with a 2D finite element model in which  motions of the fault is controlled by a slip weakening friction law. The numerical results show that earthquakes occur in a typical pattern of characteristic earthquakes: there are 6 large earthquakes during the 1 000 a simulation, the intervals between two adjacent earthquakes are about 161±4 a, and the seismic moments of per unit length for each earthquake is about 1.13×1020  Nm/km. There is a small earthquake with a seismic moment of 5.62×1018  Nm/km occurred between each two-adjoin large earthquakes. The coseismic and interseismic surface deformations of the numerical model agree well with the GPS observations. The uncertainty of the elastic parameters has limited effects on the coseismic and interseismic deformations, while variations of the viscosity influence the interseismic deformations. The numerical results also show that if the interseismic deformations were only controlled by the motion of the fault, the gravity anomaly of this model would decrease linearly during the interseismic period and reach about -370 μGal at about 100 km from the trench on the continent. Variations on velocity mainly happened within the first 5 a and velocities change little about 5 a after each earthquake.

]In traditional plane fitting methods for point clouds, people don’t consider errors in data and in coefficients matrix simultaneously, which will result in incorrectness of plane parameters. In order to overcome this shortcoming, a new method for fitting local plane to point clouds was proposed. The method is based on total least squares. In consideration of the errors in all observation data, we tried to delete outliers from point clouds, and thus obtained a robust solution to plane fitting parameter. Analytical experiments based on simulated data and real data were conducted, and comparisons between the method and traditional methods such as least square method and eigenvalue method were also implemented. The results show that the method has the capability to overcome bad influence from outliers, and to increase the reliability of parameters estimation.

The sources of some primary low frequency noise effecting on strong motion acceleration are analyzed. To remove the noise, three schemes of baseline correction are introduced, and the effect of the schemes on the velocity and displacement time series integrated the processed acceleration is pointed out. Apply the schemes, three typical accelerations of Wenchuan Ms8.0 earthquake are corrected, and some questions are also put forward for the consideration of baseline correction.

As the world map which is published on the net by State Bureau of Surveying and Mapping has no the concrete projection parameters and the normal and inverse transformation formulae, it is difficult to project the geoinformation to the map. We derived the formulae of the normal and inverse solution of equivalent difference latitude parallel polyconic projection. Throught choosing the reference points, and computing the projection parameters from the coordinate values of reference points, people can make the transformation of geoinformation according to the normal and inverse transformation formulae, and project the dots, lines or panels to the map easily.

The applicability of the recursive algorithms of fully normalized associated Legendre functions (FNALFs) is an important indicator to evaluate their quality.  We discuss four recursive algorithms of FNALFs including the standard forward column algorithm, the standard forward row algorithm, the recursive algorithm between every other order and degree, and the Belikov algorithm.  The applicability of these algorithms are evaluated and compared from three aspects: the first relative numerical accuracy, the second relative numerical accuracy, and the computation speed and efficiency.  We prove that the applicable intervals of standard forward row algorithm are the least.  While θ∈[-1,1], the standard forward column algorithm, the recursive algorithm between every other order and degree, and the Belikov algorithm are applicable for degrees less than 1 900, the first algorithm is the fastest.  Furthermore, the recursive algorithm between every other order and degree, and the Belikov algorithm are applicable for degrees less than 3 000, with the latter being the best.

Local Moran index and GetisOrd local G are the mostly common indices used for the analysis of local spatial autocorrelation.The two indices are compared based on simulated space by designing several spatial congregation schemes
and their characters in finding the local spatial autocorrelation are analyzed.It is concluded that GetisOrd local G is better than local Moran index.

The operating principle of the newtype photoelectric autocollimator is introduced and its errors is analyzed.

Based on a novel asynchronous compared method the emptyfull flags of the FIFO were generated,
achieving the flag and clock synchronization by using latches. The related Verilog HDL codes were also illustrated.

Limitations of conventional satellite altimetry are summarized. The principles of four new altimetry techniques including Kaband altimetry, constellation technology, GNSS altimetry and wideswath altimetry are introduced.The advantages and disadvantages of these new techniques are analyzed. The implementation of these techniques will complement the conventional altimetry, and greatly extend the applications of satellite altimetry.

To accomplish spatial rectangular coordinate transformation with big rotation angles, the improved coordinate transformation model is proposed. This model is based on scale parameter estimation using the matrix singular value decomposition (SVD). Three estimation methods, including direction cosine, unit quaternion and Rodrigues are presented for the improved coordinate transformation model. Finally, simulated and practical experiments of coordinate transformation with big angle are tested to compare and analyze the adaptability of the three methods using the total number of singular points, the condition number of normal matrix, the number of iterations and the RMS, etc. Experimental results show that the improved model is better than the extant seven parameters model, that the SVD solution of rotation matrix is superior to unit matrix as an initial value, and that the direction cosine method is preferable to the other two methods.

We analyze the neo-tectonic characteristics and their evolution in the Weihe basin. Based on the faulting segment study of the north Qinling fault, the faulting activity of the Kouzhen-Guanshan fault may correspond to the segment of the north Qinling fault, which has the strongest faulting activity. Then the influence of the Kouzhen-Guanshan fault, including other north margin faults of the Weihe basin, are modelled by FEM, under the condition that the north Qinling and the Huashan front faults are the main and controlling active faults in the Weihe basin. The results show that the faulting activity of the Kouzhen-Guanshan fault corresponds to the east segment of the north Qinling fault. Furthermore, as a preexisting and unsubstantial tectonic belt fault, the Kouzhen-Guanshan fault is easier to aggravate the above-mentioned effect and has stronger faulting activity than other north margin faults of the Weihe basin.

With the developments of satellite, radio communication, and computer technology, autonomous operation of satellite navigation system becomes more and more important. Inter-satellite Link (ISL) is a key technology. The Walker constellation structure, and its categories, frequencies and rules of intersatellite links are introduced.Besides, the construction method and visibility of intersatellite links of Walker constellation are analyzed and then, the azimuth, elevation, and range are computed as well. Study shows that multiple ISLs can be built in Walker constellation.