On the basis of the broadband tiltmeter data, the earthquakes are located with sourcescanning algorithm(SSA). The results show that under the condition of three seismic stations, for outside network earthquakes, with uniform spherical shell model, the location precision decreased with the increasing distance from the network, and in the nearest station is 878 km, the longitude error is -1.11°and the latitude error is 2.73°. At the same time, we found that there may be problems in the time system of Huangmei station and Ningshan station in December 2008 to April 2009.
Using the leveling repetition data of Fuqing and Quanzhou comprehensive sites, the crustal deformation of the regional repetition gravity data was corrected, the magnitude order of that effect is less than 10×10-8ms-2. The processing results of GPS data show that the movement of three groups of faults across the comprehensive site decreased gradually from east to west, the movement velocity is the same as the southern China block.
Based on ANSYS finite element software for numerical simulation analysis, the strain monitoring ability is initially explored by 9 analog observation points in Shanghai municipality. It is proved in theory that comprehensive deep seismic observation system could access crustal deformation information in the seismic active period under the current crust movement level.
The nonfrequency interference test, the frequency interference test and the electrical sounding test had been conducted in the Wuhan Jiufeng seismostation. The observations showed that the Wuhan Jiufeng seismostation could be rebuilt to the geoelectric field observation.
Strain tidal observation data at Macheng station from 2001 to 2010 were applied to conduct a comprehensive quality assessment and longterm stability. Results showed that strain tide observation data of Macheng station during 10 years were continuous, complete, reliable and equipments kept stable. Data integrity rate was high, zero drift of years and annual variation were small, precision of strain tide observation was high and the relatively noise level was low. Five evaluation indicators had reached the domestic leading level that were data continuous rate, zero drift of years, annual variation, tide factor of M2 wave, and relative error and noise level. The results could provide longterm and reliable data for geodynamics, and also provide a reference instance for the variation information of solid tidal background and identification on precursory anomalies.
The SSY extensometer status in Changshu seismostation from 2008 to 2011 was analyzed, through the continuous rate of the data, the noise level of the observational data and the relative mean error of M2 wave amplitude factor, the quality assessment was studied, the results show that: 1) the value of the continuous rate of extensometer is more than 99.6% in the case of no lightning; 2) the noise level and relative mean error of the M2 wave amplitude factor are in line with the deformation regulatory requirements, and they are stable; 3) SSY extensometer is mainly affected by the interference effects of barometric pressure and rainfall, and the greatest impact is rainfall.
On the basis of the observation data of VP type broad frequency band tiltmeter in Linfen seimmostation, the overall elaborate change process of seismogenic system before Hejin M4.8 earthquake was recorded: 1)one year before the earthquake, the curve had the performance of α、β、γ stage anomaly form;2) The slow earthquakes were recorded from 35 days before and 7 days after the earthquake; 3) Frequency spectrum analysis showed: one month before the earthquake, the amplitude magnified obviously in frequency range of 0.1, 0.3 and 0.5 Hz, in the month of the earthquake occurring, the amplitude strengthened in frequency range of 0.1-0.5 Hz; 4) Two months before the earthquake, the loadunload response ratio appeared the high and low level fluctuation, and the loadunload response ratio figure was increscent with arrival of the earthquake.
The typical distortion phenomenon of earth tidal curve from horizontal pendulum at Linfen seismostation before the earthquakes is analyzed, the probability of typical fluctuation appearance before the earthquakes is calculated in both space and time, the physical mechanism of the typical abnormal events is explained.The analysis results can be a preliminary judgement condition of earthquake.
Soil seismic response analysis procedures EERA of the University of California and the RSLEIBM procedures of China Seismological Bureau were utilized, and by using the typical earthquake wave(EIcentro wave) with different peak as the input ground motions, the ground motions were calculated under each program, and the calculated results with two procedures were almost same.
The contrast observations of two HiTarget VNet6 observing equipments and Trimble NetR8 and NetR9 observing equipments had been made in the Tangshan GNSS outdoor test field, and the results were analyzed, on this basis, we discussed the prospect of this equipment used in crustal movement monitoring.
We calculated the magnitude of the stress sensitivity coefficient of the borehole strainmeter which was impacted by modulus of cement, cement thickness, the thickness of steel tube and modulus of rock.The results showed that:1)When the modulus of cement is smaller than a fixed value, the sensitivity coefficient of body stress increases with increasing of the modulus of cement.When the modulus of cement is bigger than the fixed value, the sensitivity coefficient of body stress decreases with increasing of the modulus of cement.2)When the ratio of cement layer’s thickness is less than 2, the body stress sensitivity coefficient changes violently, and it was affected greatly by cement layer’s thickness.3)The sensitivity coefficient of body stress drops with the increasing of the thickness of steel tube and modulus of rock.
The frame structure uses laminated rubber bearings base isolation, according to the basic conditions of laminated rubber bearings, using the ANSYS software to establish the calculation model of the isolated structure, the damping effect of this structure in the rare earthquake is analyzed through a specific example. Finally, two conclusions are proposed. 1)The application scope of rubber bearings base isolation is not only associated with the structure of the height to width aspect ratio, but also associated with the structure of the natural period. If the vibration period of the structure is greater than 1, the damping effect of the isolated structure will be significantly decreased. 2)Laminated rubber bearings base isolation can be applied to the pure frame structure with the following 14 floors ; the 14 layer can be used, but the damping effect is not good;14 floors above can not be used.
This paper introduces the basic principle and calculation method of the seismic load on the slope dynamic response analysis.Taking the slope of Guojiaba in Zigui as an example,using the different timeprocedure data under the action of seismic load respectively,inputing finite element calculation software directly,we can obtain the different dynamic responses under different seismic load,such as slope displacement and shear stress stress,etc.
By using frozen soil extreme depth data from specifications for the first and second order leveling of State Standard of the PRC, the Frozen Soil Extreme Depth Query System is designed based on Arc Engine plus .net framework.Combined with the description of station data from 15 level lines such as Yanghong line and Shashi line in Jinjimeng monitoring network, the query results are verified with 1.16 cm of error mean and 1.70 cm2 of error variation which could achieve the requirements of practical application.
A peak acceleration method of different seismic ground motion, a intensity converting method of seismic ground motion peak acceleration and a fitting method of extreme value were compared which were proposed by the new edition of “seismic ground motion parameters zonation map of china”. The seismic ground motion peak acceleration value of eleven cities along the BeijingShanghai highspeed railway was obtained based on the seismic safety evaluation report, the values of the safety evaluation report was compared with those with three methods. The result could provide reference for the value of seismic ground motion peak acceleration of seismic design.
This paper introduces a seismic intensity meter design based on memsaccelerometer,taking the STM32F107 as the sampling and data processing core,three axis mems accelerometer LIS344ALH detected acceleration changes,ADS1248 sampled the high precision 24 bit.Filtering three axis acceleration data,selecting effective peak ground acceleration(PGA),seismic intensity is calculated.The test shows that the performance parameters of seismic intensity meter fully achieve the desired design requirements.
The design of integrated sealand airborne laser scanner is proposed.In order to collect simultaneous land and waterdepth measurements,high frequency dual wavelength laser and large dynamic optical receiver are used.The system uses self calibrating timetodigital converter to rebuild the high precise point cloud data.The modulation and demodulation techniques based on coded orthogonal frequency division multiplexing are used to transmit airborne point cloud data back to ground stations.
By using the chip ADS830,we designed a highspeed data acquisition system of laser interferometer signal based on FPGA,then saved the converted data to the internal SRAM through the FPGA internal cache.
A new method of measuring falling object posture is presented in order to solve the deflection of absolute gravimeter falling object.The method uses a single laser triangulation principle to analyze the relationship between optical parameters, and the selection of components and installation of structure are based on the parameter values.The result shows that the distance can reach micron level resolution in the short distance measurement (1-10 mm).
Two types of errors in the measured distance of the test masses are studied,when the masses of absolute gravimeters has been rotate in the freefall.The one is caused by refractive indices of the retro reflector,the other is due to the retro reflector rotate by the center of mass.The relationship between both errors and the size of the reflector and the rotation of the test mass are researched.
Aiming at the problem on target satellite recognition in satellite laser ranging(SLR) observing system. A scheme which could reduce image noise is provided by image limited accumulation and linear operation. The scheme of reducing image noise is realized with MATLAB language programming. Finally, the barycentric coordinate of the target which is recognized in LLL(Low Light Level) TV CCD can be obtained. The result shows that this scheme is effective to recognize the target satellite in the image obtained from SLR observing system.
The principle and method of measuring the distance of free falling objects and its corresponding time intervals used in absolute gravimeter are introduced. The importance is that highprecision time measurement chips TDC502 is used to better the precision of time measurement,and combining the largescale integration of digital design, the precision of gravimeter system will be improved.
The effects of different filtering techniques on the daytime observations were presented, including the spatial filtering, the frequencydomain filtering and the timedomain filtering techniques. The design scheme of spatial filtering and its implementation in the SLR system were described in great details. The experimental results indicate that this spatial filtering technique can suppress the daytime background noise effectively and enable the daytime observation of satellite laser ranging.
In China, the Urban Seism Intensity Rapid Report System (USIRRS) needs a lot of collected stations to acquisition seismic data. We propose a scheme that the ARM microprocessor as the controller, controlling the ADC converting the signal which the MEMS accelerometer collected, and transmitting the macroseism data by Ethernet. The data of the seismic signal acquisition complied with the relevant requirements of the macroseism data acquisition.
The principle of sinusoidal excitation source system developed with direct digital synthesis ( DDS ) technology is systematically introduced and established by using simulation module of matlabsimulink. The simulation results show that amplitude stability and high frequency stability problems of the past sine circuits are basically resolved by improved to 10-6-10-7 and 10-4 , respectively. Moreover, the precision of gravimeter has been increased.
Based on the dial indicator in a wide range(0 to 30 mm)plus stepper motor device test the resolution and the main performance indicators of the JSYID Type Digital Hydrostatic Levelling Telemeter.The test results meet the industry standards of Capacitance Leveling Transducer;The technical problems of the overall measuring instrument are solved from the quantity transmission side.
This remote seismic monitoring system is combined by a remote compute and strong vibration data acquisition terminals which are based on GPRS DTU.Because of transmitting the data by the Internet,this system has the great advantages of small size,convenient installation and operation,and low cost.
Data recorded by the MEMS accelerometer and the traditional seismometer are compared.And the feasibility of earthquake monitoring of the MEMS accelerometer is discussed.
The measurement principle and software/hardware designs of a seismic trigger based on the MEMS accelerometer are introduced.This instrument can detect peak ground acceleration(PGA)and cumulative absolute velocity(CAV).If the test result exceeds the set threshold,the seismic switch will give alarm command.
Measuring principle,installation requirement and monitoring results of CCD type alignment and introduced.The test result in the Tingzikou hydroengmeering verifies that the instrument has the advantages of good stability and no drift.
An observation method of optical autocollimation system based on CCD is proposed and the image processing method is introduced.At first,autothreshold segmentation is used to detect the pixel edge of reticle.Then,the integral method is used to locate the pixel edge of reticle.The following processing is cubic polynomial fitting which fit the image edge to implement subpixel localization.Finally,straight line fitting is applied and the center of reticle is obtained.The experiment results show that the subpixel division can detect the subpixel edge of reticle precisely.
Taking the seismic instrument system which was used in a nuclear power station as an example,the basic principle,structure and performance of the seismic instrument system is introduced.This system can meet the actual demand of nuclear power station which with high accuracy and reliability,and wide frequency band.
The seismic wave signal generator is designed,which is made up of two parts: a waveform output unit and a frequency pulse counter unit.The waveform output unit can generate conventional waveform signals,storage waveform signals and seismic waveform signals,respectively.According to application and testing results,the seismic wave signal generator can basically satisfy the application requirements.
Passive vibration isolation system based on the spring can be simplified as hanging spring oscillator model by the equivalent conversion.The transfer function of the model can be calculated using its dynamics equations,and the mathematical model can be set up.By giving the typical input signals to the established modelstep signal,pulse signal and sine signaland carrying on the simulation,both ends of system natural frequency spectrum has the vibration isolation effect,with the loss of the system natural frequency,vibration isolation performance of the system at high frequencies is improved,but has amplification effect on the low frequency signal.
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.
Based on the observation principle and data storage model of VPbased broadband vertical pendulum tiltmeter,using the combination algorithm of empirical mode decomposition(EMD),STA / LTA energy ratio and leastsquares fitting,via C++ and MATLAB programming realization,the tiltmeter automation observation is optimized while achieving automatic identification of abnormal signal and automatic zero,and improved the quality of data acquisition and application.The effectiveness of the method has been verificated through examples.
Based on the MEMS technigue a set of earthquake early warning pickup device was designed.The design adopts GSK166 shaking table to test the device,and compared with the standard sensor AC43 through the metrological verification,the test result shows that the device performance parameters meet the requirements of earthquake early warning system.
Some foreign earthquake prediction systems were compared,combining with the current situation of earthquake prediction system in China,the problems and difficulties in the establishment of the earthquake prediction system in China were pointed out.
〗Aiming at the problem of the pointing error of satellite laser ranging, the six groups observation data from Changchun SLR station and Wuhan mobile SLR station are analyzed, and the distribution of pointing error is also studied, We propose a model which uses a mount model after dividing the observation data by the genetic algorithm. The result shows that the error distribution of elevation and azimuth angles has certain regularity, and the residual error does not necessarily meet the normal distribution, and the genetic algorithm can improve the accuracy of model.
This paper introduces earthquake monitoring and early warning system for Japanese railways by stages,and then analyzes the earthquake early warning systems for high speed railways constructed in China.Finally,taking the BeijingTianjin high speed railway for example,some advices are given to improve the distribution of seismic stations.The system will provide from zero to tens of seconds warning time after these improvements.
The traverse survey record program used eMbedded Visual Basic 3.0(EVB) programming language, the total station instrument equipped with bluetooth communication function by using the serial Bluetooth adapter, the automatic data recording between total station and Pocket PC(PDA) has been realized, so as to get rid of the manual input operation mode, reduce errors and improve work efficiency.
We focus on the key technology and implementation of environment monitoring stations, the XML and JSON technologies were displayed by realtime curve with the rich client language tool Flex in remote environment monitoring, and the client user experience was further enhanced in the seismostation environment monitoring, and it was used in the seismostations in the earthquake administration of Shanxi province with a good response.
The common faults and causes in daily operation of “fifteen” digital precursory observation system in Shanxi were analyzed, and corresponding maintenance on specific issues was proposed.
Some technical problems in installation of the TJⅡ borehole strainmeter are discussed based on the TJⅡ borehole strainmeter installation experience of Shandong province.