地下水宏观异常与强震临震预报

阐述了如何利用地下水宏观异常作强烈地震的临震预报，详细叙述了利用地下水宏观异常预报地震三要素的方法。     

中强地震前油井动态异常机理研究

在分析油井映震特征的基础上，着重对油井动态异常的形成机理进行了研究。认为：映震灵敏井孔的空间分布主要受应力易于集中的构造条件的控制，特别是断层的又汇处、转折端和断裂带，这是与其他流体观测项目的相同之处；在本研究中，首次提出了油井动态前兆异常形成的三种力学过程，即岩土力学过程、水动力学过程和气体动力学过程以及油井特有的二种”放大”作用（变径和气体膨胀）的观点；解释了油井动态震前多为正异常的力学机制。     

A mixed finite element method for Hele-Shaw cell equations

A new numerical method to solve the system of equations describing two phase flow in a Hele-Shaw cell is presented. It combines a mixed finite element method, the method of subtraction of the singularity and a front tracking grid in a single computational strategy. This choice of discretization techniques is well motivated by the difficulties present in the system of equations and the physics of the problem. The new method was tested against analytical solutions and also by solving the Saffman–Taylor viscous fingering problem for finite and infinite mobility ratios. In both cases convergence under mesh refinement is achieved for the fingers developed from an initial sinusoidal interface. Finger splitting is observed for low values of the surface tension and high mobility ratio. Different explanations, based in our results, are provided for this phenomenon. This revised version was published online in July 2006 with corrections to the Cover Date.     

The Zihuatanejo, Mexico, earthquake of 1994 December 10 (M= 6.6): source characteristics and tectonic implications

An analysis of the Zihuatanejo, Mexico, earthquake of 1994 December 10 ( M = 6.6), based on teleseismic and near-source data, shows that it was a normal-faulting, intermediate-depth ( H = 50 ± 5 km) event. It was located about 30 km inland, within the subducted Cocos plate. The preferred fault plane has an azimuth of 130°, a dip of 79° and a rake of −86°. The rupture consisted of two subevents which were separated in time by about 2 s, with the second subevent occurring downdip of the first. The measured stress drop was relatively high, requiring a Δσ of about a kilobar to explain the high-frequency level of the near-source spectra. A rough estimate of the thickness of the seismogenic part of the oceanic lithosphere below Zihuatanejo, based on the depth and the rupture extent of this event, is 40 km.
This event and the Oaxaca earthquake of 1931 January 15 ( M = 7.8) are the two significant normal-faulting, intermediate-depth shocks whose epicentres are closest to the coast. Both of these earthquakes were preceded by several large to great shallow, low-angle thrust earthquakes, occurring updip. The observations in other subduction zones show just the opposite: normal-faulting events precede, not succeed, updip, thrust shocks. Indeed, the thrust events, soon after their occurrence, are expected to cause compression in the slab, thus inhibiting the occurrence of normal-faulting events. To explain the occurrence of the Zihuatanejo earthquake, we note that the Cocos plate, after an initial shallow-angle subduction, unbends and becomes subhorizontal. In the region of the unbending, the bottom of the slab is in horizontal extension. We speculate that the large updip seismic slip during shallow, low-angle thrust events increases the buckling of the slab, resulting in an incremental tensional stress at the bottom of the slab and causing normal-faulting earthquakes. This explanation may also hold for the 1931 Oaxaca event.     

松辽盆地白垩系的密集段及海水进侵的新证

在总结松辽盆地白恶系层地层特征的基础上，阐述了密集段的地质学和地球物理学标志，经分析，大多数重要反射与密集段相关而并非是层序边界，根据扫描电镜分析结果，在密集段中首次发现了钙质超微化石，为区内白垩纪海水进侵的提供了新的证据，由稳定同位素分析，密集段形成了缺氧，相对可容纳空间最大及水体最深时期。     

应变软化在甘肃红柳河辉长质糜棱岩形成中的作用

本文论述的辉长质糜棱岩发现于甘肃北山红柳河蛇绿岩套中。在简单说明了糜棱岩的地质背景及特征、描述了变形岩石的显微构造特征之后，重点对糜棱岩形成过程中的应变软化机制作了论述。探讨了软化岩的存在、组构调整、粒度缩小，长石的动态重结晶，水以及主导变形机制的不断调整与转化等应变软化机制，在应力作用下使岩石逐步软化过程中所起的作用，得出这种糜棱岩是在拆离剪切作用下，应力在蛇绿岩中的软化岩石辉长岩中集中，从而形     

Transport in a 2-D saturated porous medium: A new method for particle tracking

A new method for solving the transport equation based on the management of a large numbe of particles in a discretized 2-D domain is presented. The method uses numerical variables to represent the number of particles in a given mesh and is more complex than the 1-D problem. The first part of the paper focuses on the specific management of particles in a 2-D problem. The method also would be valid for three dimensions as long as the medium can be modeled similar to a layered system. As the particles are no longer tracked individually, the algorithm is fast and does not depend on the number of particles present. The numerical tests show that the method is nearly numerical dispersion free and permits accurate calculations even for simulations of low-concentration transport. Because each mesh is considered as a closed system between two successive time steps, it is easy to add adsorption phenomenon without any problem of numerical stability. The model is tested under conditions that are extremely demanding for its operating mode and gives a good fit to analytical solutions. The conditions in which it can be used to best advantage are discussed.     

Recent Advances in Prediction and Processing of Strong Ground Motions

We present an overview of our recent results on utilizing small earthquakes in the earthquake engineering practice. Site-specific ground motion time-histories of large earthquakes can be successfully simulated using recordings of small earthquakes which are often referred to as 'empirical Green's functions' in seismology. Another important practical problem is whether and how these observations can be used in seismic risk studies which are based on empirical attenuation relations for ground motion parameters. We study a possibility of extrapolating attenuation relations for small earthquakes, to larger magnitudes using the data from the Garner Valley downhole array in Southern California. Finally we introduce efficient ground motion processing techniques in frequency- and time-domains and apply them to site response estimation.     

Early Estimation of Strong Aftershock Duration Time

In order to solve the problem of early estimation of moderately strong aftershock duration time in an earthquake sequence,this study has been conducted.First,the definition of the strong aftershock has been given.It is pointed out that there is a difference in the strong aftershock duration time between the main shock type sequence and the strong earthquake swarm sequence.After dividing the three cases,i.e.,a strong aftershock duration time larger than 1 day,smaller than 1 day,and no strong aftershock occurred in a main shock type sequence by using the pattern recognition method,we gave the rough correlation relation between strong aftershock duration time and first large shock magnitude for two types of sequences.Finally,the judgment index and method of estimating strong aftershock duration times for different sequence types have been given.     

Relocation of the October 9, 1505 Earthquake with M63/4

There have been 12 possible locations of the earthquakes occurring in the South Yellow Sea since 1505.In this paper,the location of the earthquake that occurred in 1505 has been determined by the collection of more historical data of the influenced field,referring the isoseismal data of earthquakes with the epicentral intensityⅨ and combining geophysical field data with tectonic condition,due to its great influence on seismic safety assessment of some significant engineering.