兰州大尖山地震台阵勘址

介绍了兰州大尖山核试验监测地震台阵的勘址工作，包括本地区的地质背景、气象条件以及中心建筑（CRF）和各子台建筑的的工程地质情况。该台阵投入观测后表明：台阵所在地区的气象、地质条件等观测环境完全满足全面禁止核试验条约组织国际监测系统（CTBTO／MS）勘选台阵的要求。兰州大尖山地震台阵的建成，进一步提高了甘肃省兰州市及周边地区微震活动的监测能力。     

Seismic activity at the western Pyrenean edge

The present-day seismicity at the westernmost part of the Pyrenean domain reported from permanent networks is of low to moderate magnitude. However, it is poorly constrained due to the scarce station coverage of the area. We present new seismic data collected from a temporary network deployed there for 17 months that provides an enhanced image of the seismic activity and its tectonic implications. Our results delineate the westward continuity of the E–W Pyrenean band of seismicity, through the Variscan Basque Massifs along the Leiza Fault, ending up at the Hendaya Fault. This seismicity belt is distributed on a crustal scale, dipping northward to almost 30 km depth. Other relevant seismic events located in the area can be related to the central segment of the Pamplona fault, and to different E–W thrust structures.     

Lithospheric structure of the Tornquist Zone resolved by nonlinear P and S teleseismic tomography along the TOR array

The main aim of the TOR project is to study the lithospheric–asthenospheric boundary structure under the Sorgenfrei–Tornquist Zone, across northern Germany, Denmark and southern Sweden. Relative arrival-time residuals of teleseismic P and S phases from 51 earthquakes, recorded by 150 seismic stations along the TOR array, were used to delineate the transition zone in the studied area. The effects of crustal structures were investigated by correcting the teleseismic residuals for travel-time variations in the crust based on a 3D crustal model derived from other data. The inversion was carried out for S phases. The results were then compared with the corresponding P-wave models. As expected, the derived models show that the relatively old and cold Baltic Shield has higher velocity at depth than the younger lithosphere farther South. The models show two sharp and distinct increases in depth to velocities which are low compared to our reference model, as we move from South to North. The location and sharpness of these boundaries suggests that the features resolved are, at least partially, compositional in origin, presumably related to mantle depletion. A sharp and steep subcrustal boundary is found roughly coincident with the southern edge of Sweden. This is below where the edge of the Baltic Shield is usually placed, based on surface geological evidence (the Sorgenfrei–Tornquist Zone). Another less significant transition is recognised more or less beneath the Elbe-lineament. Relatively high d(V_p / V_s) ratios under the central part of the profile (Denmark) indicate relatively low S-velocity in an area where a gravity high supports the hypothesis of extensive mafic intrusions.     

Definition of subsoil structure and preliminary ground response in Aigion city (Greece) using microtremor and earthquakes

An extensive campaign—including detailed geologic and geotechnical surveys both existing and news as well as noise measurements—was conducted along a cross-section in order to define both geometry and soil properties (mainly the shear wave velocity) of the main formations in Aigion city. Aigion city is located in the Gulf of Corinth, Greece, a highly seismic region of the Aegean Sea. The main objective of the accurate 2D soil model is its use in site response modeling and in the interpretation of observations from a vertical down-hole accelerograph array. This model revealed a complex geologic structure with a multi-faulted shear zone related to the Aigion fault. The defined subsurface structure offered the possibility for its correlation with estimated site effects, in terms of spectral ratios. Two different data sets, earthquakes recorded at down-hole accelerograph network and noise measurements at 17 sites, were used. To translate the empirical transfer functions with the geologic structure, the 1D estimates were also computed. All these results are consistent, indicating a satisfactory correlation between the soil model and preliminary site response.     

被动源电磁阵列系统及其在某铜矿区的应用试验

本文介绍被动源电磁阵列系统的特点及该系统在某铜矿区的应用试验工作。与已知资料对比,试验结果给出了地下矿体的空间赋存形态,为矿区下一步工作提供了有意义的参考资料。     

提高卫星三线阵CCD影像空中三角测量精度及摄影测量覆盖效能

利用数字模拟方法,进一步探讨了类似MOMS-02参数的卫星三线阵CCD影像单航线、航线首末4角隅设一个控制点(以下简写为单航线4控点)的空中三角测量高程精度低的问题。研究得出,宽高比特别小(1:9)只是原因之一,更主要的因素还在于平差整过程数学关系带有近似性(包括EFP法和定向片法)。提出了改善精度的措施,并拟订了提高卫星三线阵CCD影像空中三角测量精度及摄影测量覆盖效能的系统。模拟计算表明,航线长度可以≥2B,在有外方位元素或无外方位元素少量控制点条件下,不论二线交会区,还是三线交会区均可达到高程精度为6m的摄影测量成果。     

地震台阵滤波及子台分布对聚束效果的影响(Ⅰ)——滤波与相关性的规律

以上海余山实验地震台阵的测震记录为基础，研究了近震事件、远震事件及噪声不同的幅频特征，分析了影响台阵记录之间相关性质的一些主要因素：当子台间距增大时，记录之间相关性降低；当间距固定时，所记录事件的相关性质受信号的频率、震中距(波阵面的入射角)及噪声振动背景的影响，提出了一维时间序列滤波函数的优化结果并不是二维台阵的最佳频率窗，欲取得较好的聚束信噪比，滤波函数不仅考虑压制噪音振动，还要考虑压制信号的非相关频段。     

时域激电法单极-偶极装置在金矿勘查中的应用

文章简述了勘查区地质概况、矿化类型和时域激电单极-偶极布极方式,结合实例说明该装置在确定金矿体的形态、产状等空间位置方面有较好地质效果.