Attenuation of shear-waves in the back-arc region of the Hellenic arc for frequencies from 0.6 to 16 Hz

Q_β for shear-waves is determined for the inner part of the Hellenic arc, the back-arc area, as a function of frequency in the range 0.6–16 Hz. We used 314 digital records from 32 earthquakes with magnitudes (M_w) ranging from 3.9 to 5.1. Epicentral distances ranged from 65 to 515 km. The data were obtained in 1997 during a 6-month operation of a digital portable network in Greece. The Q_β estimates were made for five frequency bands centred at 0.8, 1.5, 3.0, 6.0 and 12.0 Hz and the Q_β values obtained were 47, 79, 143, 271 and 553, respectively. The results show that Q_β for S-waves increases with frequency taking the form Q_β=55f ^0.91 (or Q_β⁻¹0.018f^−0.91). The high attenuation and the strong frequency dependence found, which is close to the frequency dependence of coda Q for Greece, are characteristic of an area with high seismicity, rapid extension, and in agreement with other similar studies in Greece.     

A bilinear approximation of the surface relief in terrain correction computations

A new method is presented for the computation of the gravitational attraction of topographic masses when their height information is given on a regular grid. It is shown that the representation of the terrain relief by means of a bilinear surface not only offers a serious alternative to the polyhedra modeling, but also approaches even more smoothly the continuous reality. Inserting a bilinear approximation into the known scheme of deriving closed analytical expressions for the potential and its first-order derivatives for an arbitrarily shaped polyhedron leads to a one-dimensional integration with – apparently – no analytical solution. However, due to the high degree of smoothness of the integrand function, the numerical computation of this integral is very efficient. Numerical tests using synthetic data and a densely sampled digital terrain model in the Bavarian Alps prove that the new method is comparable to or even faster than a terrain modeling using polyhedra.     

GPS与INSAR数据融合研究展望

分析了GPS与INSAR数据融合的必要性与可行性 ,讨论了GPS与INSAR数据融合存在的主要问题 ,进一步探讨了利用GPS数据改善INSAR相位解缠算法 ,利用GPS与INSAR数据融合建立水汽模型和大气层延迟误差改正模型 ,以及GPS高时间分辨率和高平面位置精度与INSAR高空间分辨率和高高程变形精度有效统一的问题。     

氯对测定化合水的影响及其校正研究

用差热和热（失）重法、ｐＨ值检验、离子色谱等分析方法考察和证实了Ｃｌ－对平菲尔特管重量法测定化合水（Ｈ２Ｏ＋）的干扰，研究其影响规律，提出用系数校正方法可获得Ｈ２Ｏ＋的准确结果。方法用于含氯深海沉积物和大洋多金属结核标准物质中Ｈ２Ｏ＋的定值分析，取得满意结果     

用非线性遗传反演方法进行自动静校正

静校正处理是消除近地层影响的一个重要地震资料数字处理方法，在近地表层纵，横向变化复杂，静校正量变化较大的地区，常规静校正方法和线性反演方法均不能解决问题，遗传算法是近年发展起来的一种模拟生物生化过程的较先进的非线性反演方法，对用遗传算法进行静校正的若干问题进行了讨论，说明它是可以解决表层情况复杂地区静校正问题的一个有效方法。     

评价储层含油性的热解参数校正方法及其应用

评价储层含油性时，热解参数Ｓ１＋Ｓ２是一项有效参数。其中Ｓ２相对稳定，Ｓ１则随样品类别或露置时间的不同而发生变化。岩心样品的随钻解分析值比较接近真实，岩屑和井壁取心样品的Ｓ１会明显损失。而目前多数探井心进尺少，大多为岩屑录井。     

二维地电条件下充电法地形改正的一种方法

本文首先讨论了充电法地形改正方法及存在的问题，提出了一种基于比值法思想的地改方法，经理论模型验算表明，有较好的地改效果     

山区三维地震勘探大时差静校正及时深转换

山地煤矿采区地形条件复杂，正确进行大时差静校正是处理好二维地震勘探资料的重要一环。大时差静校正会改变煤层反射波时间(t0)及双曲线特征，为减小校正误差，需设立一个CMP面，将校正量分为高频分量和CMP校正量。在地形高差变化剧烈的山地，不能用高于地表面的统一基准面为零线进行时深转换，须进行充填层时差(△t)校正，将统一基准面校正到地表面，再以地表面为零线进行时深转换成图。以便准确无误的展示煤层赋存形态，提高构造图精度。     

Study on Ground Motion Attenuation Relation in Shanghai and Its Adjacent Region

Based on intensity data in Shanghai and its adjacent region, the intensity attenuation relation is determined. Selecting the western United States as a reference area where there are rich strong ground motion records and intensity data, and by determining ground motion attenuation relation in an area lacking in strong ground motion data, we obtain the ground motion attenuation relation in Shanghai and its adjacent region.     

GPS水汽遥感中的大气干延迟局地订正模型研究

在GPS遥感水汽过程中,大气干延迟模型的精度直接影响水汽遥感的精度。根据广东清远站1995～2001年的气象探空资料,计算了GPS水汽测量中的实际大气干延迟。在此资料基础上,利用地面气象要素建立了大气干延迟的年和分月局地订正模型。分析结果表明,年模型的精度优于目前广泛使用的普适模型;月模型与年模型相比,效果不是很明显,建立局地分月订正模型意义不大;在对高度角的敏感程度上,局地模型略大些;当高度角小于75时,大气干延迟弯曲路径与直线路径之差ΔS随天顶角增大而迅速增大。