分形理论在滑坡预报中的应用研究

以长江新滩滑坡和甘肃黄茨滑坡为研究对象,采用分形理论,初次提出滑坡动态位移分维、速度分维预测模型及滑坡大滑的分维预报式,为滑坡动态预报提供新的途径。     

中尺度涡旋的雷达探测和分析

应用单部多普勒天气雷达观测资料对出现在京津冀地区的中尺度涡旋进行了分析，分析结果表明:发展较强的中小尺度天气系统往往与风场的旋转或辐合辐散有关，气旋性涡度场对积云对流活动有明显的组织和增强作用，是降雨增强的一种判据。     

利用测震台网记录获得加速度波形的方法研究

研究了从测震台网速度记录获得高质量加速度波形的方法，并以天津蓟县台安装的CTSI-EDAS24速度型甚宽带地震仪和EST-Q4128型强。震仪对同一地震记录的处理分析为例，对计算步骤和处理方法进行了详细论述。处理结果的对比分析表明，该方法简单有效，拓宽了数字测震台网波形记录的服务应用范围。     

On the Role of Wind Direction in ERS SAR Signatures of Internal Waves on the Iberian Shelf

The relationship between internal wave (IW) signatures in Synthetic Aperture Radar (SAR) images and wind velocity is investigated. The effect of the wind velocity relative to the IW propagation direction on the IW signature is studied by means of a defined signature mode parameter ( S m ). S m is the parameter that quantifies the signature of the IW intensity profile in relation to the mean backscatter of the image background.

A wind contrast model based on a simple first-order Bragg scattering theory is combined with hydrodynamic modulation theory to explain the modulation of IW signatures. It takes into account the modulation of short-scale surface waves by the effect of the relative variations of wind velocity and the surface currents generated by the IWs.

It is shown that the signature mode parameter increases with the angle between the wind velocity and the IW propagation direction so that IWs propagating against the wind direction are imaged mostly as positive sign signatures, while those propagating in the wind direction are mostly negative sign signatures.     

A study on amplification response of soil ground motion in Shanghai using strong motion records

Introduction A good deal of attention was paid to the amplification response of soil layers under the earthquake waves,especially by the engineering seismologists.     

VELOCITY AND SUSPENSION CONCENTRATION IN SEDIMENT-MIXED FLUID

1 INTRODUCTION AND REVIEW Numerous investigations related to vertical velocity and suspension concentration distributions have been undertaken to the steady, uniform, open channel turbulent flow. The problems of sediment mixed water flows are of direct interest to the practical situations in the field of river sedimentation, coastalsediment transport and in the field of two-phase flow in particular. In hydraulic open channel flow, the vertical velocity profile is usually described by…     

三维叠前深度偏移速度分析及蒙特卡洛自动层速度拾取

是否能够正确地建立深度域三维速度模型是三维叠前深度偏移成败的关键 .本文根据Deregowski循环 ,利用叠前深度域地震成像对速度模型变化的敏感性 ,采用偏移迭代逐次逼近最佳成像速度 ,研究开发了一套快捷有效的三维叠前深度偏移深度域速度模型建立技术 .借鉴时间域CDP(共深度点 )道集上常规叠加速度分析的策略 ,在深度域CRP(共反射点 )道集上 ,提出剩余慢度平方谱的概念并建立相应的实现技术 .导出深度域中均方根速度与层速度之间的关系 ;按照串级偏移原理确定偏移循环过程中初始速度、剩余速度及修改后速度之间的关系 ;采用蒙特卡洛非线性优化算法实现从剩余慢度平方谱中自动拾取层速度 ,讨论了其地质速度约束条件和蒙特卡洛非线性优化的收敛准则 ,使得所拾取的层速度模型具有合理的地质意义并获得最佳偏移成像效果 .SEG EAGE理论模型数值试算验证了方法的有效性 ,在海拉尔盆地霍多莫尔工区 ,5 8km2 三维资料的速度模型建立并获得满意的三维叠前深度偏移成像 .     

On the interference between closely-spacedP arrivals recorded at seismic arrays

The arrival at the Yellowknife Array (YKA) of closely-spaced P-waves having slightly different values ofdT/d, azimuth, and amplitude has been simulated using synthetic 1 Hz wavelets. Adaptive-processing determinations of apparent slowness and azimuth show a remarkable pattern of fluctuations with time for varying separations of the interfering pulses. In the critical separation range 0.30 to 0.55 s, these fluctuations greatly exceed the differences in arrival vectors of the primary wavelets themselves. Observation of characteristic interference patterns on real array seismograms might permit the identification of triplications associated with radial velocity anomalies in the lower mantle. Processed YKA seismograms for three events at distances close to 90° are presented, which, despite apparently simple P onsets illustrate the pattern of drift indT/d expected for such a triplication.Contribution from the Earth Physics Branch No. 648.     

Velocity changes associated with generalized triaxial deformation of pyrophyllite

Compressional and shear-wave velocities (V _p andV _s ) were measured during the generalized triaxial deformation (i.e. _{1 2}=2 ₃) of pyrophyllite. Observed velocity changes could be ascribed to crack development during dilatancy. Velocity changes were very localized with respect to the ultimate failure plane. The orientation and development of the failure plane was continuously observed with laser holography. Velocity reverals, i.e. changes from a decreasing trend to an increasing trend, were documented in a wet sample in bothV _p andV _s . These changes in bothV _p andV _p are inconsistent with dialatancy-diffusion models. The reversals were interpreted as a reflection of local stress reorientation caused by a slowly propagating fault.     

热水条件下透辉石的摩擦本构特征

为了研究下地壳主要造岩矿物之一的辉石在摩擦滑动中的力学性质,本文选择辉石中的透辉石作为实验样品,在约200 MPa有效正应力（30 MPa孔隙水压）及100~600℃的热水条件下进行了速度阶跃摩擦滑动实验,在滑动开始后将剪切滑动速率在0.122 μm·s^-1和1.22 μm·s^-1之间进行切换来确定摩擦滑动对速度变化的响应.通过实验发现：透辉石在102~200℃表现为速度强化,随着温度升高,在约215℃附近从速度强化转变为速度弱化.在310℃以上,速度弱化的程度受温度的影响不大,而且摩擦本构参数a值和b值随温度的变化趋势相同.对变形样品的显微观测发现,与其速度强化行为相对应的微观变形主要以数条平行的R1剪切为主,卸样时造成的裂纹集中在R1剪切内部,形态长而曲折;与其速度弱化行为相对应的断层泥内部,剪切带变窄且数量明显增加,在内部互相连接,在边界附近多发育B剪切,卸样时形成的裂纹大量存在于B剪切带与R1剪切附近,形态短且平直.