Statistical properties of seismicity of fault zones at different evolutionary stages

We perform a systematic parameter space study of the seismic response of a large fault with different levels of heterogeneity, using a 3-D elastic framework within the continuum limit. The fault is governed by rate-and-state friction and simulations are performed for model realizations with frictional and large scale properties characterized by different ranges of size scales. We use a number of seismicity and stress functions to characterize different types of seismic responses and test the correlation between hypocenter locations and the employed distributions of model parameters. The simulated hypocenters are found to correlate significantly with small L values of the rate-and-state friction. The final sizes of earthquakes are correlated with physical properties at their nucleation sites. The obtained stacked scaling relations are overall self-similar and have good correspondence with properties of natural earthquakes.     

Crustal Stress Measurement for Significant Project Construction and Its Application in Design

The hydrofracturing technique has developed into a reliable and practical method for determining the original three-dimensional crustal stress state of underground caverns,the load-bearing capacity of a high pressure cavern itself,and the high pressure hydraulic permeability of rock masses,and has also been extensively used in disposal of nuclear waste,long and deeply-buried traffic channels and high-pressure cavern engineering for hydraulic power plants.The practice shows that the comprehensive measurement of the physical parameters of the rock mass and taking full use of the wall rock load-bearing capacity to optimize the engineering design hold are very useful in ensuring the engineering safety and improving the design level.     

青藏高原北缘深部地壳结构特征及其形成机制探讨

柴达木盆地－祁连山地区位于青藏高原北缘，同青藏高原主体一样，该区具有多层地壳结构特征，并普遍出现壳内低速层，地壳厚度是华北及华南地区的2倍以上。其形成可能与地壳的横向挤压缩短及幔源物质的底侵作用有关。随着底侵作用增强，地壳厚度加大，岩石圈厚度则越趋于减薄，地壳上部表现为拉张，下部发生壳幔深熔及幔源流体的交代作用，从而导致了地壳低速层，地热和浅源地震的发育。同时，这也是青藏高原出现热壳冷幔的原因之一。     

由APRGP97～APRGP99的GPS联测资料确定的亚太地区地壳形变

使用伪无基准（pseudo nonfiducial）算法、利用GIPSY软件，归算了APRGP97、APRGP98 和APRGP99的GPS资料．对大多数站所得解的站座标的精度:南北分量是1～2mm，东西分量是2～5mm，垂直分量是5～10mm；并初步获得亚太地区84个站在ITRF97中的运动速度，其水平方向的精度约为1～4mm/a．基于ITRF97速度场建立一个新的现今全球板块运动模型ITRF97VEL，由此获得这些站相对于该模型的现今形变速度，并对这些站相对欧亚板块的运动情况作了初步分析．