Simulating result of tectonic stress field in the upper crust under different water storage conditions for Badong Ms5.1 earthquake occurred in 2013 shows that this earthquake occurred in the gradient zone between the Badong and Niukou equivalent stress Dvalue zone which means that the Earthquake is related to the impoundment.The epicenter region possesses the tectonic background of moderately strong earthquake and the condition of massive stripped karst developed along a structure plane.The seismography data show tectonic and collapsed characteristic of the Earthquake.Comprehensive analysis suggests that Badong Ms5.1 Earthquake might give priority to tectonic mechanism.Regional tectonic stress was superimposed by the local tectonic stress state’s adjustment due to the impoundment.It might form stress concentration and collapse in the karst region developing along the structural plane.The collapse then lead to structure instable and slipping.The two kinds of mechanism feedback、alternate、superimpose and then the earthquake occurred.Therefore,the Earthquake is a new type of reservoir earthquake type—tectonic subsidence type.
The seismotectonic background and genesis of Badong Ms5.1 Earthquake was analyzed based on the regional seismotectonic environment and main seismogenic structure.According to the comparison of distribution of intensity,focal mechanism solutions and seismic wave and spectrum of mainshock and aftershocks of the Earthquake with other earthquakes near by,especially Longhuiguan Ms5.1,1979,a conclusion can be drawn that Badong Earthquake is typical reservoirinduced and tectonictype earthquake.
Based on the research of the Ms5.1 earthquake sequence in Badong, the earthquake sequence belongs to the main shock type. The frequency and magnitude of the aftershocks were attenuated ups and downs. Ms5.1 earthquake event located in NEE direction near the southen tip of Gaoqiao fault and Daping fault,at a depth of 5 to 7 km, tectonic earthquake. According to the results of earthquake precise positioning, the hypocenter parameter analysis and focal mechanism solutions,it is concluded that the earthquake is a stereotype reservoir earthquake, caused by fault tectonic stress adjustment, and triggered under the condition of reservoir high water impoundment (high stress).
Badong Ms5.1 earthquake in Hubei province caused various damages involving some of rural buildings,and seismic casualty is appeared in meizoseismic area.Based on the field investigation in the earthquake effected area,in this paper,primary characteristics of the typical damages of this earthquake are summarized.Analysis showed that:The meizoseismal area of Ⅶ degree area,which focused on the town of Badong County rang SongjialiangZi area,was NWSE trending,long axis length of 3.9 km,the minor axis length of 2.4 km,an area of about 7.7 km2.Ⅵ degree area was nearly the whole thing to the long axis of about 21.4 km,minor axis length 13.6 km,area 25.1 km2.The map of seismic intensity are trustworthy.Damages have a greater relationship with the seismic performances of buildings.This buildings of the Three Gorge immigration engineering is largely intact.Initial discussion some relationships of the intensity and faults、karst distribution.
Badong Ms5.1 earthquake in Hubei province caused various damages of simple buildings.The typical damage characteristics of adobe structures mainly includes partial collapse and vertical crack.While the damage patterns of masonry structures partial collapsing and falling.The analysis result of strong ground motion of the Earthquake show that ground motion concentrates in highfrequency contents and its predominant period is of 0.1 s,which might lead to heavy damage of onestorey simple structures.Poor stability of structure system of simple houses,insufficient intensity of components,and weak connection of nodes are the intrinsic factors of seismic damage.
Investigation of the damage characters and disaster loss of localstyle dwelling houses,caused by Badong Ms5.1 earthquake,on Dec.16,2013,Hubei Province indicates that the main reason causing the change of the rural construction cost is the cost of raw materials.In all the cost of raw materials,the increased cost of rebar and concrete is the greatest impact.It is neccessary to improve seismicresistance ability of the rural projects,and the government must give appropriate financial support.
The method of population gird data spatialization base on sample instend of region’s statistical data and rapid loss assessment in Badong earthquake was introduced in the paper.The results show that the method reflects actual population distributio,and the result of assessment is credible.The method the can quickly provide disaster information of spatial orientation after the Earthquake.
Quasistable adjustment has been carried out to the Three Gorges mobile gravity data since 2010.Six gravity change maps and four gravity change time series curves were obtained.The results show that 1)It is neccessary to test scale value in processing gravity data.2)From 2010,gravity changes curves in Buzhuanghe and Liantuo station are related to water level changes of Changjiang River and its branches.Therefore,the gravity data in the stations should not be used.3)Befores Badong Earthquake,the gravity values rise and fall repeatedly.Badong Earthquake occured in the time when the gravity value was between rising and falling.
Isostatic gravity anomaly in Badong area was calculated using the Airy model.The results show that the isostatic gravity anomaly ranged from -45×10-5ms-2 to 45×10-5ms-2,the most of the region was in the gravity isostatic state.Weak positive anomaly and weak negative anomaly appeaed in local areas,and weak positive isostatic anomaly presents in strip.The study shows that Taihang,Wuling gravity zone basically was in isostatic state with some differences in the internal.The northwestern in Badong area might occur isostatic adjustment.Badong Earthquake region was in the gravity isostatic state,that means the Badong Earthquake does not relate to the isostatic adjustment.
The data of cave strain at Yichang Seismostation before the Ms 5.1 HubeiBadong earthquake were analyzed with conventional numerical method and wavelet transform method.The result shows the start time of excavation near by was consistent with the time when the abnormal appeared.However,the mean square variance of observation values was larger than that caused by excavation as 2 times.Therefore the abnormal related to not only the load fluctuation of excavation,but also to other confounding factors or crustal strain changes.
The images of gravity variation before and after the MinxianZhangxian Ms6.6 earthquake,based on gravity data recorded by the gravity net in Gansu province show that,there are some similar characteristics with other earthquakes:1)Before the earthquake,there was a prominent positive gravity anomaly variation amounting to 70×108ms-2 in the south area of the epicenter;2)After the earthquake,gravity variation in the same area was negative,and the positive gravity anomaly variation disappeared.In addition,we found that the calibrate factors of the instruments could affect the result of gravity variation and should be detected and corrected.Our result could provide some reference to research of mechanism of this earthquake.
The variation Characteristics of earth electrical property in the period before and after M5.1 Badong Earthquake in December 16,2013 was analyzed using transfer function parameter with geomagnetic data.The results show that in the period form the beginning of 2012 to the day when the Badong earthquake occured,earth electrical property in Danjing Observatory and Gucheng Observatory appeared abnormalities with different depth.The superficial and deep transfer function parameter synchronously accelerated rising in Dangyang Observatory.
Tidal deformation observation data from the stations within 400 km of the epicenter of Badong 5.1 earthquake were analyzed with abnormal recognition method of tidal tilt and strain.The results show that there is no obvious changes before the earthquake,and it is unable to obtain the valuable information according to further calculating.
To provide earthquake science products and emergency services for the community promptly after earthquakes,automatically processing and posting of earthquake science products and emergency services are realized through selfprogramming,based on China Seismic Information website.The example of Ms5.1 of Badong Earthquake indicates that the earthquake science products and emergency services offered by the method are feasible and reliable.
Lunar vehicle’s kinematic positioning is the base of lunar exploration,so prediction of Lunar vehicle’s velocity is very important.A model for Lunar vehicle’s kinematic positioning based on “current” velocity and kalman filter is presented in the paper.The experimental results of simulation and tests with the data from China VLBI Net show that high precision position and velocity of lunar vehicle can be got by this method and it is an effective method to solve Lunar vehicle’s kinematic positioning.
This paper chooses several IGS tracking stations which distributed in coastal and inland regions of globe,uses the basic theory of the effect of ocean loading on station displacement to design a variety of programs to process the monitoring data.The results show:1)The effect of ocean tide loading on the station elevation was cm level;2)The effect of ocean tide loading on troposphere zenith delay estimation was mm level 3)There exists weak linear relationship between the troposphere effect of ocean loading and the influence of elevation.
According to the characteristics of deformation data and noise propagation on wavelet transforming in various scales,a new threshold estimation method and threshold processing function are proposed,and applied to establishment of time series model for deformation observation data.The advantage of improved wavelet denoising method is demonstrated,and the precision of prediction value is higher than that with the conventional methods.
A new method for 3D-circle testing was presented.In the method,all observed points are fitted to a plane,and the sphere can be fitted by mid vertical planes,which are composed of the space vector,the 3Dcircle center locates in the fitted plane.The coordinates of the center and the radius can be calculated by the method directly.The gross error will be eliminated during the fitting process.Compared with other methods,the method is very easy to realize,and reliability and fitting precision are higher.
Using GPS data of Crustal Movement Observation Network of China observed from 1999-2013 and data of Continental Tectonic Environment Monitoring Network of China from 2009-2013,combined with other published GPS velocity field were analyzed and a more complete horizontal velocity field covering the Tianshan mountain and its vicinity was obtained.Preliminary results Indicare that presentday strain rate field is consistent with the longterm tectonic settings in the Tianshan mountain and its vicinity.The deformation of Tianshan mountain is mainly characterized by nearly northsouth crustal shortening,and the principal compressive strain rate is about 45×10-9/a in the western part (~77°E),and about 10×10-9/a in the eastern part (~86°E).The northern Pamir thrusting fault zones and its northern TransAlay Range are in a compression,state,with a principal compressive strain rate of about(50-60)×10-9/a and with dilation rate of about(40-50)×10-9/a ,consistent with previous studies of 10-15mm/a crustal shortening rates observed from GPS velocity profiles in this region.In the eastern part of Pamir (~38°N),which is adjacent to the Tarim Basin,principal strain rate and dilation rate demonstrate that there is certain extension with a rate of about(10-20)×10-9/a .Direction of the extension is nearly westeast,which is consistent with the extensional strain state observed from previous geologic and seismic studies in this region.The other maximum shear strain rate,40×10-9/a ,appears in the northern Pamir thrusting fault zones,and another high value,30×10-9/a ,appears in the western Tianshan mountain (~78°E).
Resent horizontal deformation field in the northeastern margin of QinghaiTibetan plateau was analyzed,using GNSS observation data from 2011 to 2013.The results indicate that:The horizontal movement from 2011 to 2013 is obviously,with the rate of 15mm /a or lower;The direction of principal compressive strain is SENW,with the strain rate of ±40×10-9/a,The region of maximum main strain locates in the south of the study area in a belt;Dominent surface shrinkage indicates that the strain energy is accumulated in compressional way,the largest surface shrinkage value mainly distributed in the southeast corner;The regings with maximum shear strain rate are showed as belts,one of them is Qilian Tectonic Belt,another is in the south of the study area,parallelling with the Belt;Leftlateral area and dextral area distribute in belt.
The features of receiver clock and satellite clock are the key factors to affect the precision of zenith total zenith delay when ZTD is computed by zerodifference precise point positioning.Experiments show that solution precision of troposphere parameter is largely affected by the clock jump.A reasonable strategy for this is given.Under the circumstance of site’s coordinates being fixed,the relation between receiver clock and ZTD parameters are enhanced,and ZTD’s precision will reduce with reduction of receiver clock precision,vise versa.The result analyzed 7.21data from Bejing and Fangshan stations indicates that real time PWV can be derived by IGS predicted product and PPP skill,and corresponding precision reaches 2-3 mm,which can satisfy the need of weather forecast.
The parallel combination deformation prediction models were studied.According to the weighted constraint criterion,five kinds of deformation parallel combination prediction models were established,including suboptimal weight combination,optimal weigh combination,synthesis relational grade of greyweight,entropyweight and artificial neural networkweight.Based on the characteristics of the models,the effects of parallel combination prediction under different constraint criterion are compared.The results of analysis with real data show that the nonlinear combination prediction based on neural network is the best one.
The incidence angle has an impact on point clouds accuracyin 3d terrestrial laser scanning.For improving the accuracy,a method of weighted total least squares (WTLS)incidence angle weighting for point clouds plane fitting is proposed.In the method,the weight value of each point is determined by incidence angle,and the weight matrix is defineson the basis of the structure characteristics of coefficient matrix.The experiments with point clouds data of the plane made of three different materials show that the method is more reasonable and more accurate than least squares (LS)and total least squares (TLS).
The horizontal velocity field of the northeastern QinghaiTibet plateau is acquired by using the GPS data observed between 2011 and 2013.The current crustal movement in the northeastern margin of the Tibetan plateau is consistent with the long term motion.The north Qilianshan fault is experiencing the deformation of contraction and leftlateral shear,and the shortening rate is larger than the strike slip rate.The horizontal shortening rate of west part of north Qilianshan fault is larger than that of the east part.The GPS velocity profile across the west part of north Qilianshan fault shows that the strain is accumulating while the underneath of this fault is locking.The profile perpendicular to the Liupanshan fault demonstrates that the shortening is distributed at the west of Liupanshan with a range of 300 km.There is no differential movement in the vicinity of both sides of Liupanshan.Therefore,Liupanshan fault is locked deeply.The profile parallel to DiebuBailongjiang fault and west Qinling shows that there is a strikeslip deformation gradient between them.LinxiaTanchang fault is located at this gradient and the shear strain is accumulating.The 2013 Minxian Ms 6.6 earthquake might be associated with this elastic strain accumulation due to locking.The tectonic motion of Longmenshan fault and surrounding area has been basically restored to horizontal movement before the 2008 Wenchuan earthquake.
Land surface subsidence caused by mining may damage buildings,and disaster loss can be reduced by accurate prediction of surface subsidence.The actual geological and surveying data of 21 mining area in Tangdong coal mine were calculated ground deformation of goaf areas with the probability integration method.Overlay analysis of subsidence contour map and topographic map by ArcGIS verifies that probability integration method can accurately forecast ground subsidence.caused bymining.
Polynomial fitting and interpolating of precise or broadcast ephemeris will be affected by Runge’s phenomenon.Satelites’ position and velocity information were used to remove the influence of Runge’s phenomenon.The result shows that the outside precision of 8hour fit interval can reach millimeter level.
Navigation Constellation may drift in secular operation because it lacks the inertial benchmark only based on the measurements of intersatellites links.Firstly,the technique of groundbased anchomethod is used to deal with the observability of the constellation in theory.Then,AREFK(AugmentR Extended Kalman Filter)algorithm is used to settle the problem of the distributed autonomous orbit determination of the navigation constellation and validated the simulation lastly.The simulation results indicate the autonomous orbit determination can satisfy the needs of accuracy of the navigation and position.
A method for realizing highprecision point positioning in a certain area by fixing the broadcast orbits to estimate precise satellite clock was presented in the paper.Different distribution strategies of reference stations during the clock estimation are analyzed with PANDA and a group of optimal distribution strategies of reference stations in our country is proposed.The experiment results show that the positioning accuracy of 1 cm (static)and 5 cm (dynamic)can be reached using the clock estimation with broadcast orbits with this strategy.
The applicability of total least squares studied systematically with data fitting.The relationship formula between total least squares residual distance and least squares residual distance was obtained and extended to the multidimensional cases.According to the relationship among the criterion of least squares (LS),data least squares (DLS)and total least squares (TLS),the applicability was determined.
The information entropy theory was introduced into parameter estimation of variogram model,to improve weighting method of weighted polynomial regression using the entropy weight method.An experiment was taken with real deformation monitoring data,considering the influence of both distance and the number of point pairs at the same distance.The experimental results show that the variogram model determined by information entropy weighted regression is more reasonable,and interpolating prediction is more accurate.
A method to constructe a reliable functional model and a stochastic model for clock error based on the theory of refining filter model by timefrequency analysis,power spectral density,autocorrelation and Allan variance was proposed.Comparison of the results calculateed with random walk type and with GaussMarkov type shows that only by using GaussMarkov type clock model together with the autocorrelation analysis of correlation time,the variation disciplinarian of clock can be represented properly.
A New global weighted temperature model(GWMT_N) was built using reanalysis data during 2007-2011 offered by NCEP to solve the remarkable limitation in ocean area of Global Weighted Mean Temperature (GWMT)model.Periodically semiannual effect of Tm was taken into account in the new model.The accuracy of GWMT_N model was verified with 650 radiosonde stations in 2011 and COSMIC occultation in 2011.The results show that GWMT_N successfully avoid the limitation of GWMT,and its accuracy on land was even improved.The overall accuracy of GWMT_N is equivalent to that of Bevis formula.For the new method does not require observed temperatures on land,it can be applied more widely in GPS meteorology.
RungeKutta method was introduced to GLONASS orbit simulation to analyze how the step length parameter effects on simulated results,the efficiency of RungeKutta method and the difference between simulated results and broadcast orbit.The result shows that step the balance between algorithm efficiency and accuracy can be keeped though setting step length as 1 s-300 s.The difference between simulated results and broadcast ephemeris increases with time,and reaches about 250m in X,Y,Z directions for 300 minutes simulation time duration.It takes 2 ms to simulate 1 epoch 24 satellites orbit data.According the research,RungeKutta method can be used for GLONASS orbit simulation.
The result of contrast test of A10/028 absolute gravimeter with FG5 was introduced.The measurement results with the two kinds of gravimeter indicate that there is little difference between A10/028 and FG5,the difference of accuracy is within±5× 10-8 ms-2.A10/028’s precision of inner coincidence is ±(2~3)×10-8 ms-2,with stronger antiinterference ability.
For the reason that GOCE gravity gradients is impacted badly by low frequency error,three filtered methods were designed based on the spectral characteristics of GOCE gravity gradients.The best method was choosed through comparison of the results with the three methods.The method was applied to filter 70 days gravity gradients between 2009-11-02—2010-01-10.An Earth’s gravity field model with 200 degree and order was reconstructed based on 70 days filtered gravity gradients.The results show that reconstruction of model have to be processed with regularization.The precision of the regularized model is consistant with that of GO_CONS_GCF_2_TIM_R3 with 160 degrees.The results prove that the designed method can filter gravity gradients successfully.
The gravitational gradients along the orbit observed by GOCE satellite is given in the gradiometer coordinate system(GRF)while the Earth’s gravity field model from gradients is generally in noninstrument coordinate system.Due to GOCE can not measure full tensor gradient efficiently,it is necessary to replace VXY、VYZ as model values and to converse coordinate system of gradient.Therefore,in the rotation process,the error of the gradients data and the error of the rotation matrix have be taken into account.A pointwise rotation model of gradients in various coordinate systems and analysis the impact of various errors in conversion process of gradients were described,and gradients tensor rotation strategy is discussed simultaneously.Actual processing results show that the attitude error of the GOCE meets the design requirements,but the quality of GOCE gradients tensor,is not good for containing a large number of lowfrequency colored noises,which needs to filter before conversion.In addition,“removerestore” method can significantly improve the accuracy.
A new prediction method based on the combination of gray system model and wavelet neural network is proposed.Firstly,fitting given satellite clock bias values with gray model,and determining parameters of gray model with the values.Then,establishing model of wavelet neural network with fitting residuals.Finally,combining the prediction results obtained from the two models mentioned above to get prediction results.The results of prediction tests using the precise satellite clock bias data from IGS show that the method can get better satellite clock bias prediction results,compared to the quadratic polynomial model and the grey model.Especially for the rubidium clock of ⅡR type and ⅡF,the prediction precision can be provided with two times or more.
A method of conventional weighted total least squares was proposed based on the robust weighted total least squares for eliminating the influences of point clouds anomalous points in laser scanning data on fitting precision.The method can be used to correct adaptively the weight of observation vector and and coefficient matrix,and remove anomalous data.The result of fitting analysis with the point clouds from different distances shows that the fitting accuracy with the method is better than the conventional methods.
The accuracy of satellite position,velocity and clock errors of global positioning system(GPS)broadcast ephemeris were analyzed in the paper.The results reveal orbits errors are less than 2 m,mean value and rootmeansquare(RMS)of satellite clocks are less than 8 ns,velocity errors less than 0.5 m/s and signalinspace range error(SISRE)less than 2.5 m.Compared with the consquence in 2006,positions,velocities and clocks are improved.
The inconsistency of three frequency carrier phases of Block IIF satellites (PRN01 with PRN25)causes difference between the satellite clock biases (SCBs)derived from L1/L2based ionospherefree linear combination and the SCBs obtained from L1/L5based ionospherefree linear combination.The SCBs’ inconsistency between L1/L2 and L1/L5 is called interfrequency clock biases (IFCBs).IFCBs of Block IIF satellites (PRN01,PRN24,PRN25,PRN27)were obtained by processing the data from 37 IGS network stations.Analysis for the features of these IFCBs indicates:1)The epochdifferenced method is more efficient than the undifferenced one;2)All the Block IIF satellites exist apparent IFCBs,whose magnitude are approximately in centimeter to decimeter;3)The periods of 12,6,8 and 4 h can describe the IFCBs’ periodic variation better than other period groups.4)The model is also suitble for PRN24 and PRN27 Block IIF satellites.
In the case of big inclination angle,traditional methods extracting the center of circular planar target in TLS do not work and a part of data will miss.A new algorithm based on edge fitting is proposed.The firstl step is to extract automatically edge points of circular plane target,The second step is to fitt spatial circle by edge points and determine the center of the target.Experimental results show that this algorithm is simple and feasible,the extracting accuracy is consistent with that by software in suitable conditions;In the case of big inclination angle or missing data,this algorithm can also determine accurately the coordinates of target center.
Based on PPP mathematic model,the impact of multipath error on PPP solution is investigated.The result of analysis indicates that all positioning parameters,such as solution constant interval and sampling rate,have to be consistent with each other on different observation days in opperating PPP sidereal filtering.Sidereal filtering can be applied to low sampling rate observations by Lagrange interpolation of position error time series,which spreads its application and decreases calculation amount.Experimental result analyzing the data from IGS tracking stations shows that accuracy of PPP kinematic position accuracy can be improved with the sidereal filtering by 692%,72.3% and 27.6% for the East,North and Up components