The　Q　value　variations　in　the　preparing　pro－cess　of　rock　rupture     

王彬  许昭永  赵晋明  胡毅力 《地震学报(英文版)》1996,(4)

ＴｈｅＱｖａｌｕｅｖａｒｉａｔｉｏｎｓｉｎｔｈｅｐｒｅｐａｒｉｎｇｐｒｏ┐ｃｅｓｏｆｒｏｃｋｒｕｐｔｕｒｅＢＩＮＷＡＮＧ１）（王彬），ＺＨＡＯ－ＹＯＮＧＸＵ１）（许昭永），ＪＩＮ－ＭＩＮＧＺＨＡＯ１）（赵晋明）ＹＩ－ＬＩＨＵ２）（胡毅力）１）Ｓｅｉ...  相似文献   

Lg amplitude ratios H/Z and station terms in the six eastern provinces of China     

Huancheng Ge  Caizhong Huang  Yuewei Ni  Yongqin Li 《地震学报(英文版)》1992,5(2):257-261

Using the data set of about 1 Hz Lg amplitudes from 80 stations in the six eastern provinces of China, the ratios of horizontal to vertical amplitude of Lg waves,H/Z are determined. The mean lg(H/Z)-value is equal to 0.13. For the station bases of soft deposit,granite and sedimentary rock, lg(H/Z)-values average 0.55, 0.04 and 0.10, respectively. For the three kinds of station bases, the station terms of horizontal amplitude,C _h average 0.65, −0.09 and 0.00; that of vertical amplitude,C _z average 0.32, −0.04 and 0.00, respectively. There are the relations betweenC _h ,C _z and lg(H/Z):C _h =0.01+2.10C _z andC _h =−0.15+1.46 lg(H/Z). The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 281–286, 1991. Project sponsored by the Chinese Joint Seismological Science Foundation.  相似文献   

A discussion on the amplitude ratios of PP and P waves for earthquakes with different focal mechanisms     

Yuru Zhuo 《地震学报(英文版)》1992,5(1):33-43

Using the WKBJ approximation method we calculate the synthetic teleseismograms of P and PP waves to match the observed ones of six large Chinese earthquakes with known focal mechanisms: Tibet earthquake of July 14, 1973; Haicheng earthquake of February 4, 1975; Songpan earthquakes of August 16, 1976, August 21, 1976 and August 23, 1976 and Nignhe earthquake of November 15, 1976. The focal mechanism of the Tibet earthquake is discussed to examine the technique used in the calculation. We note that the amplitude ratios of PP and P waves (A _PP/A _P) have different characteristics for dip—slip events and strike—slip events within certain epicentral distances. We calculate the synthetic teleseismograms of P and PP waves for the strike—slip and dip—slip events with fault angles of 330°, 240° and 0°, focal depths of 8 km, 17 km and 24 km, at the assumed station with an azimuth of 310° and epicentral distances from 40°; to 80°. The diagrams of maximum amplitude ratios of PP and P waves (A _PP/A _P) versus distances are given. The possibility to use the (A _PP/A _P) values to give an approximate estimation for the focal mechanism type is discussed. This work may be useful for determining the focal mechanism type for those earthquakes which have only few records such as the Chinese earthquakes from the 1930s to 1960s. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 150–160, 1991.  相似文献   

Three－dimensional　Global　Scale　Permanent－wave　Solutions　of　the　Nonlinear　Quasigeostrophic　Potential　Vorticity　Equation　and　Energy　Dispersion     

H.L. Kuo 《大气科学进展》1995,12(4):387-404

The three-dimensional nonlinear quasi-geostrophic potential vorticity equation is reduced to a linear form in the stream function in spherical coordinates for the permanent wave solutions consisting of zonal wavenumbers from 0 to n and rn vertical components with a given degree n. This equation is solved by treating the coefficient of the Coriolis parameter square in the equation as the eigenvalue both for sinusoidal and hyperbolic variations in vertical direction. It is found that these solutions can represent the observed long term flow patterns at the surface and aloft over the globe closely. In addition, the sinusoidal vertical solutions with large eigenvalue G are trapped in low latitude, and the scales of these trapped modes are longer than 10 deg. lat. even for the top layer of the ocean and hence they are much larger than that given by the equatorial β-plane solutions. Therefore such baroclinic disturb-ances in the ocean can easily interact with those in the atmosphere.Solutions of the shallow water potential vorticity equation are treated in a similar manner but with the effective depth H = RT / g taken as limited within a small range for the atmosphere.The propagation of the flow energy of the wave packet consisting of more than one degree is found to be along the great circle around the globe both for barotropic and for baroclinic flows in the atmosphere.  相似文献   

Amplitude Response of a LCR Gravimeter with Feedback at Periods of Microseisms and Earthquake Waves     

Vladimír Tobyáš  Jan Mrlina  Bohumil Chán 《Studia Geophysica et Geodaetica》1999,43(2):185-193

The amplitude response of a LCR gravimeter with the SRW-E feedback was determined on a vertical vibrating platform. The ink-pen recorder was connected parallel with the digital voltmeter input to obtain an analog response of the gravimeter to the harmonic motion of the base with a peak-to-peak amplitude of 10 m and periods excited in an interval of 4 - 10 s as by the ground motion of meteorological microseisms, and in the interval 10 -100 s as by surface waves of distant strong earthquakes. In the first interval, an unexpected maximum of the amplitude response was observed with the double amplitude of apparent 6,5 Gal (6.5 × 10 _–8 m/s ² ) at a period of 4.8 s, and a baseline shift with the amplitude of–64Gal was observed at the same period. The value of this direct component cannot be separated from the effect of the Earth's gravity field. In the second interval, the amplitude response of the gravimeter displayed one expected maximum at a period of 40 s with the double amplitude of 8.1Gal. At the usual level of microseisms with a peak-to-peak amplitude of up to 2 m the fluctuation of the gravimeter on the direct baseline shifted by –4.9 Gal was estimated at 1 Gal. With typical Rayleigh surface waves with periods of 20 s and double amplitudes of up to 100 m, the fluctuation reached 67 Gal.  相似文献   

Sensitivity of GPS and GLONASS orbits with respect to resonant geopotential parameters     

D. Ineichen  G. Beutler  U. Hugentobler 《Journal of Geodesy》2003,77(7-8):478-486

The Center for Orbit Determination in Europe (CODE) has been involved in the processing of combined GPS/GLONASS data during the International GLONASS Experiment (IGEX). The resulting precise orbits were analyzed using the program SORBDT. Introducing one satellites positions as pseudo-observations, the program is capable of fitting orbital arcs through these positions using an orbit improvement procedure based on the numerical integration of the satellites orbit and its partial derivative with respect to the orbit parameters. For this study, the program was enhanced to estimate selected parameters of the Earths gravity field. The orbital periods of the GPS satellites are —in contrast to those of the GLONASS satellites – 2:1 commensurable (P _Sid:P _GPS) with the rotation period of the Earth. Therefore, resonance effects of the satellite motion with terms of the geopotential occur and they influence the estimation of these parameters. A sensitivity study of the GPS and GLONASS orbits with respect to the geopotential coefficients reveals that the correlations between different geopotential coefficients and the correlations of geopotential coefficients with other orbit parameters, in particular with solar radiation pressure parameters, are the crucial issues in this context. The estimation of the resonant geopotential terms is, in the case of GPS, hindered by correlations with the simultaneously estimated radiation pressure parameters. In the GLONASS case, arc lengths of several days allow the decorrelation of the two parameter types. The formal errors of the estimates based on the GLONASS orbits are a factor of 5 to 10 smaller for all resonant terms. AcknowledgmentsThe authors would like to thank all the organizations involved in the IGS and the IGEX campaign, in particular those operating an IGS or IGEX observation site and providing the indispensable data for precise orbit determination.  相似文献   

Experiment Study and Interpretation on Relation between Modulus of Rock and Strain Amplitude     

Bao Xueyang 《中国地震研究》2006,20(2):190-201

INTRODUCTIONThe modulus of rock is one of the basic elastic parameters of the earth’s medium. Under theassumption of linear elastic theory and Poisson medium,other parameters can be calculated fromit .But the real earth mediumis nonlinear elastic and has not a simple linear relationship between stressand strain.This causes relatively big differences betweenthe dynamic andthe static modulus of rock.In nonlinear elastic theory,the Young’s modulusEis replaced bythe nonlinear elastic modul…  相似文献   

某动力机器基础动力学分析     

孔垂烛  薛尚铃  尹菊丽 《岩土工程技术》2007,21(5):254-256

当动力机器基础体积较大时,采用《动力机器基础设计规范》(GB 50040-96)推荐的简化计算方法进行动力计算,计算结果可能具有较大的误差而不能用于工程设计,此时进行三维数值分析是必要的。在介绍弹性动力学分析的基础上,使用通用有限元软件ANSYS8.0,对某设备基础进行了模态分析和谐相应分析,得出了该动力机器基础的低阶固有频率准确值,以及该动力机器基础随外部荷载频率改变的振幅变化曲线,进而得出一些重要结论,为该工程设计提供了可靠参考。  相似文献   

曲线拟合在核探测器信号幅度提取中的应用     

覃章健  葛良全程峰 《成都理工学院学报》2007,34(6):643-647

研究数字化核探测器输出脉冲信号的幅度提取问题。根据闪烁探测器的电路特性，推导了其脉冲信号理想曲线方程。综合利用三和值法、最小二乘法、试探法等方法，设计了该理想曲线拟合算法。由脉冲信号采样点数据，通过曲线拟合，计算出曲线的极大值，该值即为闪烁探测器输出脉冲信号的幅度。正反演数据结果对比表明，采用曲线拟合算法提取闪烁探测器输出脉冲信号幅度，其方案可行，计算结果更准确。相较于数字滤波和数字脉冲成形方法提取核探测器输出脉冲幅度，该算法更简单，对仪器的硬件处理速度要求更低。该方法开辟了核探测器脉冲幅度提取的新途径。  相似文献   

Three-dimensional geometrical ray theory and modelling of transmitted seismic energy of data from the Nevada Test Site     

How-Wei Chen 《Geophysical Journal International》1998,133(2):363-378

This paper presents a geometrically based algorithm for computing synthetic seismograms for energy transmitted through a 3-D velocity distribution. 3-D ray tracing is performed to compute the traveltimes and geometrical spreading (amplitude). The formulations of both kinematic and dynamic ray-tracing systems are presented. The two-point ray-tracing problem is solved by systematically updating the initial conditions and adjusting the ray direction until the ray intersects the specified endpoint. The amount of adjustment required depends on the derivatives of the position with respect to the given starting angles between consecutive rays. The algorithm uses derivatives to define the steepest-descent direction and to update the initial directions. The convergence rate depends on the complexity of the model.
Test seismograms compare favourably with those from a 2-D asymptotic ray theory algorithm and a 3-D Gaussian-beam algorithm. The algorithm is flexible in modelling arbitrary source and recorder geometries for various smoothly varying 3-D velocity distributions. The algorithm is further tested by simulating surface-to-tunnel vibroseis field data. Shear waves as well as compressional waves may be approximately included. Application of the algorithm to a data set from the Rainier Mesa of the Nevada Test Site produced a good fit to the transmitted (first arrival) traveltimes and amplitudes, with approximately 15 per cent variation in the local 3-D velocity.  相似文献