计算震磁背景场的数学方法

如何计算地磁场 (或地磁剩余场 )及其长期变化的趋势变化 ,是提取震磁异常的关键。文章简要介绍了计算震磁背景场的数学方法 :多项式方法、球冠谐和分析方法、矩谐分析方法和曲面样条函数方法     

二滩库区蓄水前地震活动本底研究

1991年 7月建成投测的二滩水库地震遥测台网 ,经过 7年的连续运行 ,为我们提供了宝贵的第一手资料。笔者根据这些地震记录资料 ,用多种地震学方法进行分析研究后发现 ,该区域内 1～ 2级地震是库区主要的地震活动 ;小震活动基本上符合 G- R震级频度关系式 ,正常背景下的平均 b值为 0 .58;1 .5级以上地震的平均月频度为 9次 ;其能量累计蠕变也具有较好的稳定增长关系 ;地震活动的时空分布与库区几条主要断裂有一定关系。可将它们作为研究蓄水后地震活动的参照本底     

数字与模拟地震台网记录的震相特征与地震参数对比分析

本文对辽宁数字与模拟地震台网从1998年12月至1999年5月记录到震波特征、地震参数进行初步的比较与分析。     

山西临猗地震前后临汾台地电阻率变化

以临汾台地电阻率观测资料为依据,着重对临猗地震前后的异常变化进行了分析研究,并对这次地震地电阻率前兆异常形态与特征进行了探讨。     

中国大陆1998～1999年地壳运动观测结果

介绍了中国地壳运动观测网络1998～1999年基准站GPS观测概况,简要介绍了用伯尔尼（Bernese）软件对GPS观测数据的处理结果,详细介绍了所获取的1998年９月初～1999年７月初基准网地壳运动,包括各基准站位移与网内各部分的应变．在所述观测期间,我国东部地区较为稳定．相对东部地区,西南部地区以向北运动为主,位移量约17ｍｍ,受北北东向挤压为主;西北部地区以北西向运动为主,位移量约11ｍｍ;而云南地区以向南运动为主,位移量约14ｍｍ．我国中部南北地震带则是一强烈的剪切变形带．网内最大主应变量为2.910-8．观测结果表明,印度板块向北挤压依然是影响我国地壳运动的主要因素．      

辽宁瓦房店温坨子原核电站场址东岗断裂的活动性

位于辽宁瓦房店温坨子的东岗断裂是一条隐伏断层 ,靠近该地区原曾选定的核电站场址。通过详细的野外地质工作 ,查明了该断裂的地理位置、几何形态 ,发现断裂带东延至尉屯就转向北去 ,并确定它没有与金州断裂相接。经系列探槽的开挖 ,断层构造岩及有关地层样品作绝对年龄测定 ,证明东岗断层错断了中更新世地层 ;但约 5万年以来断层的上覆地层没有被错断 ,因此认为东岗断层不是能动断层     

Application of the Landsat-5TM Image Data in the Feasibility Study of Mudflow Hazards in the Southern Taihang Mountains

The Taihang Mountains area is an area in North China where serious mudflow hazards take place frequently. The hazards often obstrust traffic and make it difficult to carry out conventional ground investigations of the mudflow hazards. This paper introduces the feasibility study of mudflow hazards by using Landsat-5TM data. The study has achieved a great success through adopting both the faint spectral enhancement technique for mudflow fans (or other depositional areas) and comprehensive study of the environmental background of pregnant mudflows. Thus, remote sensing as a fast, convenient, low-cost and effective technical method can be used to recognise the situation of mudflow hazards so that effective rescue can be provided.     

Thermal and kinematic corrections to the microwave background polarization induced by galaxy clusters along the line of sight

We derive analytic expressions for the leading-order corrections to the polarization induced in the cosmic microwave background (CMB) owing to scattering of photons off hot electrons in galaxy clusters along the line of sight. For a thermal distribution of electrons with kinetic temperature k _B T _e∼10 keV and bulk peculiar velocity V ∼1000 km s⁻¹, the dominant corrections to the polarization induced by the primordial CMB quadrupole and the cluster peculiar velocity arise from electron thermal motion and are at the level of ∼10 per cent in each case, near the peak of the polarization signal. When more sensitive measurements become feasible, these effects will be significant for the determination of transverse peculiar velocities, and the value of the CMB quadrupole at the cluster redshift, via the cluster polarization route.     

Simultaneous estimation of noise and signal in cosmic microwave background experiments

To correctly analyse data sets from current microwave detection technology, one is forced to estimate the sky signal and experimental noise simultaneously. Given a time-ordered data set we propose a formalism and method for estimating the signal and associated errors without prior knowledge of the noise power spectrum. We derive the method using a Bayesian formalism and relate it to the standard methods; in particular we show how this leads to a change in the estimate of the noise covariance matrix of the sky signal. We study the convergence and accuracy of the method on two mock observational strategies and discuss its application to a currently-favoured calibration procedure.     

Large-scale structure, the cosmic microwave background and primordial non-Gaussianity

Cosmic microwave background and large-scale structure data will shortly improve dramatically with the Microwave Anisotropy Probe and Planck Surveyor , and the Anglo-Australian 2-Degree Field and Sloan Digital Sky Survey. It is therefore timely to ask which of the microwave background and large-scale structure will provide a better probe of primordial non-Gaussianity. In this paper we consider this question, using the bispectrum as a discriminating statistic. We consider several non-Gaussian models and find that in each case the microwave background will provide a better probe of primordial non-Gaussianity. Our results suggest that if microwave background maps appear Gaussian, then apparent deviations from Gaussian initial conditions in galaxy surveys can be attributed with confidence to the effects of biasing. We demonstrate this precisely for the spatial bispectrum induced by local non-linear biasing.