对地震预测研究的信心的科学基础   总被引：3，自引：0，他引：3  

吴忠良 《国际地震动态》1998,(9):1-6

结合目前围绕地震预测问题的讨论,文章论述了对地震预测研究的信心的科学基础,指出地震预测研究在科学上是有意义的,地震预测研究最突出的困难是观测的限制,目前科学的发展为向地震预测问题发起新的冲击创造了条件。  相似文献   

在97.8GHz处测量地球大气的不透明度     

杨戟  曹逸庭 《天文学报》1998,39(3):333-336

用研制的全自动辐射计在97．8GHz上测量南京市内大气的不透明度以及这种不透明度随时间的变化．辐射计记录大气在不同天顶高度的辐射温度,由此测出天顶方向的大气不透明度。在56小时的测量时间内,取得了1400多组数据,拟合得到了在观测时段内天顶方向的大气不透明度在0．2至0．7之间,典型值为0．4,表明测试地点的大气条件允许进行3mm波段的射电天文观测．由于在工作频段内大气不透明度的主要来源是对流层水汽的吸收,测量的不透明度可用来直接反映大气内水汽的含量,并实时校准大气吸收．  相似文献   

海尔—波普彗星的CO（J=1—0）谱线的观测     

裴春传  曾琴 《天文学报》1998,39(1):103-105

使用紫金山天文台青海观测站13．7米毫米波射电望远镜,于1996年12月10日至1997年1月2日和1997年3月25日至1997年4月4日对海尔－波普彗星的CO分子J＝1—0转动跃迁谱线（频率为115．27120GHz）进行了观测．观测谱线表明,CO分子相对于地心的速度比彗星整体相对于地心的速度要小些,即有蓝移现象．这反映了CO分子是由该彗星迎着太阳的面以一定的速度产生出来的．从观测谱线中还初步估算了该彗星CO分子的产生速率．  相似文献   

NEAR-FAULT DISPLACEMENT AND DEFORMATION OBTAINED FROM ONE-KILOMETER-LONG FAULT-CROSSING BASELINE MEASUREMENTS-A PRELIMINARY EXPERIMENT AT 2 SITES ON THE EASTERN BOUNDARY OF THE SICHUAN-YUNNAN BLOCK          下载免费PDF全文

CAO Jian-ling  ZHANG Jing  WEN Xue-ze  FENG Wei  SHI Yao-lin 《地震地质》1979,42(3):612-627

The current and conventional fault-crossing short baseline measurement has a relatively high precision, but its measurement arrays usually fail to or cannot completely span major active fault zones due to the short length of the baselines, which are only tens to 100 meters. GNSS measurement has relatively low resolution on near-fault deformation and hence is not suitable for monitoring those faults with low motion and deformation rates, due to sparse stations and relatively low accuracy of the GNSS observation. We recently built up two experimental sites on the eastern boundary of the active Sichuan-Yunnan block, one crossing the Daqing section of the Zemuhe Fault and the other crossing the Longshu section of the Zhaotong Fault, aiming to test the measurement of near-fault motion and deformation by using fault-crossing arrays of one-kilometer-long baselines. In this paper, from a three-year-long data set we firstly introduce the selection of the sites and the methods of the measurement. We then calculate and analyze the near-field displacement and strain of the two sites by using three hypothetical models, the rigid body, elastic and composed models, proposed by previous researchers. In the rigid body model, we assume that an observed fault is located between two rigid blocks and the observed variances in baseline lengths result from the relative motion of the blocks. In the elastic model, we assume that a fault deforms uniformly within the fault zone over which a baseline array spans, and in the array baselines in different directions may play roles as strainmeters whose observations allow us to calculate three components of near-fault horizontal strain. In the composed model, we assume that both displacement and strain are accumulated within the fault zone that a baseline array spans, and both contribute to the observed variances in baseline lengths. Our results show that, from the rigid body model, variations in horizontal fault-parallel displacement component of the Zemuhe Fault at the Daqing site fluctuate within 3mm without obvious tendencies. The displacement variation in the fault-normal component keeps dropping in 2015 and 2016 with a cumulative decrease of 6mm, reflecting transverse horizontal compression, and it turns to rise slightly(suggesting extension)in 2017. From the elastic model, the variation in horizontal fault-normal strain component of the fault at Daqing shows mainly compression, with an annual variation close to 10^-5, and variations in the other two strain components are at the order of 10^-6. For the Longshu Fault, the rigid-body displacement of the fault varies totally within a few millimeters, but shows a dextral strike-slip tendency that is consistent with the fault motion known from geological investigation, and the observed dextral-slip rate is about 0.7mm/a on average. The fault-parallel strain component of the Longshu Fault is compressional within 2×10^-6, and the fault-normal strain component is mainly extensional. Restricted by the assumption of rigid-body model, we have to ignore homolateral deformation on either side of an observed fault and attribute such deformation to the fault displacement, resulting in an upper limit estimate of the fault displacement. The elastic model emphasizes more the deformation on an observed fault zone and may give us information about localizations of near-fault strain. The results of the two sites from the composed model suggest that it needs caution when using this model due to that big uncertainty would be introduced in solving relevant equations. Level surveying has also been carried out at the meantime at the two sites. The leveling series of the Daqing site fluctuates within 4mm and shows no tendency, meaning little vertical component of fault motion has been observed at this site; while, from the rigid-body model, the fault-normal motion shows transverse-horizontal compression of up to 6mm, indicating that the motion of the Zemuhe Fault at Daqing is dominantly horizontal. The leveling series of the Longshu site shows a variation with amplitude comparable with that observed from the baseline series here, suggesting a minor component of thrust faulting; while the baseline series of the same site do not present tendencies of fault-normal displacement. Since the steep-dip faults at the two sites are dominantly strike-slip in geological time scale, we ignore probable vertical movement temporarily. In addition, lengths of homolateral baselines on either side of the faults change somewhat over time, and this makes us consider the existence of minor faults on either side of the main faults. These probable minor faults may not reach to the surface and have not been identified through geological mapping; they might result in the observed variances in lengths of homolateral baselines, fortunately such variations are small relative to those in fault-crossing baselines. In summary, the fault-crossing measurement using arrays with one-kilometer-long baselines provides us information about near-fault movement and strain, and has a slightly higher resolution relative to current GNSS observation at similar time and space scales, and therefore this geodetic technology will be used until GNSS networks with dense near-fault stations are available in the future.  相似文献   

我国地震预报的战略建议与思考     

骆鸣津  池顺良 《大地测量与地球动力学》2000,20(1):89-94

讨论了我国地震预报面对的问题和困难。认为只有加强以形变为主的前兆观测 ,才能作出地震的短临预报。目前前兆观测的主要问题在于可信度差 ,应把重点放在仪器探头上 ,只有探头提供的信息“源”可靠了 ,后续的采集、传输、预报的“流”才会有坚实的基础。我国现在建立以形变为主的前兆台网的技术条件已经成熟 ,建议建立全国高精度的高、中、低频衔接的前兆物理信息观测网络。  相似文献   

对地观测与抗震救灾   总被引：2，自引：1，他引：1  

李德仁 《测绘科学》2009,34(1)

2008年5月12汶川地震灾害发生后,全国相关涉灾部门充分利用空间信息技术为汶川地震救灾提供科学有效的决策支持,在灾害应急响应中发挥了巨大的作用。本文主要从对地观测以及地震救灾的空间信息技术支持两个方面,分析了空间信息技术在救灾中的作用。为今后空间信息如何更好地服务于自然灾害救助,提出了中国空间信息技术发展的思路与建议。  相似文献   

中国地壳运动观测网络中的GPS数据流     

许永江  郑贵明  顾国华 《大地测量与地球动力学》2000,20(4):50-56

介绍了中国地壳运动观测网络中的 GPS数据结构 ,对 GPS及其他观测数据的数据转换、数据传输、数据处理、管理及数据共享等工作流程作了详细说明。  相似文献   

川滇地区断层活动与地震关系研究   总被引：3，自引：1，他引：2  

李瑞莎  张希  王双绪  张四新  薛富平  王继英 《大地测量与地球动力学》2009,29(Z1):20-24

选取川滇地区16个跨断层形变观测点，将断层两盘作为不变形的刚体分析断面相对滑动与断层两盘地表点位相对位移的定量关系，计算了各测点的水平扭动量、垂直位移量以及两者之间的比值，并分析了其与地震活动之间的关系。  相似文献   

大气能见度研究   总被引：9，自引：1，他引：8  

傅刚  李晓岚  魏娜 《中国海洋大学学报(自然科学版)》2009,39(5)

回顾总结了国内外有关大气能见度的理论研究、仪器观测和数值模拟方面取得的成果;介绍大气能见度研究的基本理论、消光系数的概念及计算方法;总结了几种白天大气能见度探测仪的使用原理及优缺点;介绍测量夜间大气能见度和数字摄像法探测大气能见度的方法;并着重介绍4种计算与雾有关的大气能见度的经验公式,基于2004年4月11日黄海海雾个例的RAMS模式数值模拟结果,采用4种方法分别计算了大气能见度的分布并进行了比较。总结出大气能见度研究中存在的问题和今后研究的主要方向,并针对其中仍然存在的问题提出一些建议。  相似文献   

建筑物沉降观测技术方法探讨   总被引：1，自引：1，他引：0  

冯云德 《北京测绘》2009,(4):88-90

随着城市建设的迅猛发展，城市规模越来越大，建筑物越来越高，由此带来的安全隐患越来越大，由于高层建筑一般采用桩基基础，且荷载较大，对高层建筑的内部基础和设备的位置关系有很高的精度要求，其施工安装阶段将给高层建筑本身及周边建筑群体带来复杂的形变影响。为了保障建筑物施工和运营的安全，就必须对其进行沉降观测。本文结合笔者多年的实际工作经验，并结合具体的实例，对高层建筑物沉降原因、沉降观测前的准备工作及沉降观测的实施过程和观测数据的处理方法等进行了论述，最后指出如何通过沉降观测技术准确地反映出高层建筑物的沉降情况。  相似文献