高阶非线性海浪波面斜率的联合概率统计分布

基于非线笥随机海洋模型,对各向异性波面斜率统计分布进行了理论研究,结果表明,在高阶近似下,波面斜率统计分布为截断的Ｇｒａｍ－Ｃｈａｒｌｉｅｒ级数。如果忽略波－波相互作用的非线性影响,则Ｃｒａｍ－Ｃｈａｒｌｉｅｒ级数分布蜕化为正态分布。     

The Maximum Effective Moment Criterion （MEMC） and Its Implications in Structural Geology

1 Introduction A high-level generalization of structures in the earth crust has been given by Ramsay (1980): low-angle thrusts in the brittle upper crust and high-angle reverse shear zones in the ductile middle-lower crust are formed in contractional regimes; high-angle normal faults in the brittle upper crust and low-angle normal shear zones in the ductile middle- lower crust are formed in extensional regimes. The formation of low-angle thrusts and high-angle normal faults in brittle domains …     

In-situ IR measurements of OH species in quartz at high temperatures

The nature of OH species in natural clear quartz was investigated by means of in-situ IR measurements over the temperature range –185 to 1000 °C. Reversible thermal behavior of OH species was examined for a sample pre-heated to 1000 °C for 1 hour. At room temperature, the IR spectrum of the quartz sample examined includes an intense absorption peak at 3379 cm^–1 which has been assigned to an OH stretching vibration associated with Al substituting for Si (OH(Al)). The major spectral changes of the OH(Al) bond involve a systematic shift of its peak position and a decrease in its integral absorbance with temperature. A quasi-linear increase of the peak position from –185 to 400 °C is interpreted to be due to the change in the vibrational frequency of OH(Al) with hydrogen bond (H bond) distance. At higher temperatures, the IR frequency shows only a slight change, indicating a small influence of the H bond. On the other hand, the gradual decrease of the integral absorbance of OH(Al) with temperature indicates a decrease of this defect’s molar absorptivity without any reduction in defect concentration. This is interpreted to result from a decrease in dipole moment of OH(Al) with temperature. A sudden shift of the vibrational frequency from 3396 to 3386 cm^–1 between 550 and 560 °C and a constant value of the integral absorbance from 535 to 570 °C were considered to be related to the change in H bond distance during the structural transformation of α-quartz to its β-form. The local environment of OH(Al) begins to change at temperatures below 570 °C, where the crystallographic α–β transition occurs. Received: 18 February 1998/ Accepted: 10 July 1998     

地震矩张量反演在地震观测报告中的应用

针对我国地震工作的实际需要,从１９９５年起,《中国地震台网目录和地震矩张量解》刊登了国内较大地震和全球大震的地震矩张量解和震源机制解。同时在《中国地震年报》上也刊登国内及邻区较大地震的地震长张量解和震源机制解。为了方便用户使用,本文对有关参数进行了说明。     

Seismic and Aseismic Movements in the Western Bohemia/Vogtland Area

Studia Geophysica et Geodaetica -     

震级—时间可预测模型中M_0的计算方法

利用鲜水河断裂带上各断层段的滑动速率 ,用震级—时间可预测模型估算了未来强震发震概率的 M0 值 ,并和其经验值进行了比较 ,结果证明了此计算方法的可靠性     

基于小波和线矩的实孔径雷达图像与TM图像的匹配

为了充分利用多源遥感信息,常常需要解决不同传感器图像之间的匹配问题。为此,本文初步探讨了一种基于小波边缘检测与线矩描述的实孔径雷达图像与ＴＭ图像的匹配算法。实验结果表明：如果搜索窗口内存在较丰富的特征,该算法可以获得满意的结果。     

Research on the deformations in Qinghai-Tibet plateau and its margins by inverting seismic moment tensors and GPS velocities

We have determined approximate average rates of deformation in the Qinghai-Tibet plateau and its margins from the GPS data for last 10 years and the moment tensors from earthquakes between 1900 and 1999.We also determined the strain rate (seismic strain rate) associated with the seismic deformation using 254 Mw≥5.0 earthquakes,and estimated the shortening and extension rates for every block in the area as well.We also estimated the strain rate (geodetic strain rate)by 80 GPS sites' velocity vectors and analyzed characteristic of kinematics by two kinds of strain rates and discussed earthquake potential in the area.As a result,the deformation rates from seismic moment tensors and from GPS velocities are basically agreed with each other.It is feasible to analyze seismic risk by comparing geodetic strain rate with seismic strain rate based on the opinion that strain energy will be released through earthquake.It is concluded that there is no strong earthquake potential (＞M7) in the Qinghai-Tibet plateau and its margins,but there is earthquake potential (＞M5) in middle Tibet in a few years.     

水平荷载下桩的可靠性分析

由于桩及桩周土的材料性能参数的不确定性,桩的响应也是不确定的。在考虑桩的水平荷载、桩周土反力及桩的刚度等不确定因素情况下,采用一阶可靠度分析方法对水平受荷桩的最大弯矩及桩顶的最大位移进行了可靠性分析,进 而,考虑分布参数的不确定性,用点估计法预估桩的失效概率,对给定的p-y曲线进行桩的可靠性分析。研究表明,在失效概率相对较低的情况下,水平荷载下基桩的失效概率与随机变量的分布类型假定有较大关系,随机变量分布参量的不确定性只会对桩的失效概率产生较小的影响。