GPS观测得到的中国大陆地壳垂直运动

利用中国地壳运动观测网络基准站的GPS连续观测及基本站非连续GPS观测结果，分析了基准站垂直位移的年周期变化特点，讨论了获得中国大陆垂直位移长趋势速率的条件，说明由基本站（连同基准站）多期GPS观测得到的长趋势垂直位移速率是较为可靠的。由于不少GPS观测站有幅度达数cm的年周期变化及大部分区域站观测次数少，由1999年、2001年两期区域站GPS观测难以得到可靠的长趋势垂直构造运动速率。基本站的观测结果表明中国大陆长趋势垂直构造运动主要特点是，速率较低，北升，南降，东强，西弱，西部相对东部略有下降。     

福建GPS台位移时间序列分析

使用福建GPS台网2004年3月到2006年9月的连续观测资料,经数据处理获得时间序列分析结果。初步估算了各测站的运动速率和定位精度,水平向在1.5~3.2 mm,垂直向在6.6~8.2 mm。选取区域相对水平位移变化量较小的5个台站组成的一组稳定点作为基准,讨论了各测点的相对运动速率及时空变化特征。从水平位移结果分析表明,现今福建地壳运动的趋势仍十分缓慢且整体较为平稳,与华南地块同中国大陆其他地区比较呈相对稳定相吻合。     

印尼8.7级大震前后GPS观测站的地壳水平与垂直位移时间序列结果

利用IGS及中国地壳运动观测网络GPS连续观测站6年多时间的观测结果, 以中国大陆东部的稳定点组作为水平位移与垂直位移解的参考基准, 得到了2004年12月26日印尼苏门答腊8.7级与2005年3月28日8.5级大震前后GPS观测站的地壳水平及垂直位移时间序列的结果。 尽管所采用的GPS站点少, 且分布范围大, 但仍可看到在如此大的地震震前、 同震与震后地壳运动的特征, 为今后观测研究提供了十分有意义的结果。 文中所采用稳定点组基准有效消除水平位移场的平移与旋转, 而局部椭球面的不平性对计算区域地壳运动结果, 特别是对垂直位移的影响很小, 说明了位移解所描述的大范围区域位移场是合理的。 这两次地震的同震水平位移及震后的垂直位移影响量级达数厘米, 范围达远离8.7级地震震中4500 km之外, 甚至更远。     

小波分析在GPS位移时间序列特征中的应用

使用福建GPS台网2004年3月—2008年10月的连续观测资料,对各基准地震站原始数据进行处理,得到位移时间序列,进行初步分析。在此基础上,采用小波分析方法提取时间序列的时频特征,从而得到非线性变化信息,为GPS在大地震前获取前兆资料提供探索方向,进而通过对位移时间序列异常变化与区域地壳运动关系的研究,探讨两者间的内在联系。     

福建GPS台网观测位移时间序列特征的初步研究

使用福建GPS台网2004年3月至2006年10月的连续观测资料,对已作卡尔曼滤波后的时间序列观测值进行了初步分析。经数据处理估算各测站的运动速率,对连续观测结果综合分析获得位移,选取区域相对水平位移变化量较小的5个台站组成的一组稳定点作为基准;讨论了各测点连续时间序列与测站运动速率变化特征,除出现一次较明显的分量位移异常变化(可能与台湾强震活动有关)外,没有明显的水平位移异常现象。表明现今福建地壳运动趋势仍十分缓慢且整体较为平稳,是随同中国大陆地块较均匀地向东南方向运动。     

温度变化对我国GPS台站垂直位移的影响

地表温度变化可以引起GPS台站上安装GPS天线的地表水泥墩内部温度变化,还可以通过热传导的方式引起GPS台站基岩温度变化,从而引起GPS台站垂直位移变化.在中国区域,由GPS台站基岩温度变化引起GPS台站垂直位移变化的周年振幅最大可以达到1 mm;在长江以北地区,此周年振幅一般大于0.5 mm.在我国地壳运动观测网络中的23个GPS基准站中,温度变化对GPS台站垂直位移总影响的周年振幅最大值为2.8 mm,其中13个GPS基准站垂直位移的周年振幅变化大于1 mm.因此,温度变化是引起GPS台站垂直位移周年变化的一个不可忽视因素.     

用EOF分析方法研究强震前中国大陆水平位移场时空分布特征

利用大气科学常用的经验正交函数(EOF)分解方法, 对中国大陆连续观测的基准站的水平位移每周解时间序列进行分析。 首先对时间序列中不连续的数据进行内插处理, 并通过线性拟合从时间序列中去掉长期滑动速率的影响。 结合震例研究强震前水平位移场在NS向和EW向的时间和空间的分布特征。     

GPS水平位移时间序列地震短期信息特征分析

对GPS基准站连续观测水平位移时间序列数据的时-频特征进行了分析, 为了突出局部变化的信息, 在中国大陆东部选取一组参考点进行相似变换。 利用小波分析和傅里叶分析方法对资料进行处理, 分析结果表明, 2001年11月14日昆仑山口西8.1级大地震前中国大陆西部部分测点水平位移序列出现短期变化信号。     

中国地壳运动观测网络基准站水平位移向量时间序列

根据中国地壳运动观测网络基准网1998年9月初至2002年6月底GPS连续观测结果，结合各基准站的水平位移的分量时间序列，试图利用空间上更直观、更清晰的水平位移向量方法进一步说明中国地壳运动观测网络基准网水平位移测量精度、水平方向点位稳定性及2001年11月14日昆仑山口西8．1级大地震前后的地壳水平运动时空演化过程。     

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．      

关于2001年昆仑山8.1级大地震前后中国大陆地壳水平运动的讨论s

中国地壳运动观测网络基准网GPS连续观测，获得了2001年11月14日昆仑山8.1级大地震前后中国大陆，特别是西部地区的地壳水平运动信息．以东部长期相互间相对水平位移很小的几个站组成的一组稳定点作为基准， 据此获得水平位移分量时间序列．2000年11月上旬起中国西部的GPS基准站开始出现显著的异常位移，此后在云南及四川发生多次6级左右的地震．自2001年4月中旬开始，中国西部GPS基准站向北的水平位移速率明显减小，甚至反向，临震前及震后略有恢复，但震后向北的水平位移速率仍减小，并有明显的向西运动．近几年中国大陆西部（相对东部）的地壳运动过程表明，印度板块的向北挤压是昆仑山8.1级大地震的主要力源，大地震释放了大量的能量，印度板块对中国大陆的作用力明显降低，大震后至2002年底中国大陆的地震活动也明显降低．      

Horizontal crustal movement in Chinese mainland before and after the great Kunlun Mountain <Emphasis Type="Italic">M</Emphasis>=8.1 earthquake in 2001

The continuous GPS observation at the fiducial stations in the Crustal Movement Observation Network of China (CMONOC) recorded the crustal movement of Chinese mainland before and after the great Kunlun Mountain earthquake of M=8.1 on November 14, 2001, especially the horizontal crustal movement in the western part of China. Based on the datum defined by a group of stable stations with small mutual horizontal displacements for a few years, the time series of horizontal displacements at fiducial stations were obtained. Significant anomalous horizontal displacements had appeared at the fiducial stations in the western part of China since early November 2000 and several earthquakes with the magnitudes about 6.0 had occurred in Yunnan and Sichuan Provinces. The northward components of the horizontal displacement at the fiducial stations in west China had decreased significantly and even changed in the opposite sense since mid April 2001. After the earthquake, the northward displacements still decreased and there were significant westward displacements. The process of the crustal movement in the western part of Chinese mainland (in reference to east China) suggests that the main force source for this earthquake came from the northward pushing of the Indian plate. The great earthquake released a large amount of energy, as a result, the action applied by the Indian plate to Chinese mainland diminished significantly and after the great earthquake, the seismic activity in Chinese mainland decreased considerably until the end of 2002.     

Horizontal crustal movement in Chinese mainland before and after the great Kunlun Mountain M=8.1 earthquake in 2001

Introduction The great Kunlun Mountain earthquake occurred on November 14, 2001 on the border be-tween Xinjiang and Qinghai in west China (36.2N, 90.9E). It was the largest earthquake oc-curred in Chinese mainland in the last 50 years. The Crustal Movement Observation Network of China (CMONOC) established in 1998 mainly for the purpose of earthquake prediction with only 25 fiducial stations for continuous GPS observations, has recorded the precious information of the crustal movement …     

Horizontal crustal movement in Chinese mainland before and after the great Kunlun Mountain M =8.1 earthquake in 2001

The continuous GPS observation at the fiducial stations in the Crustal Movement Observation Network of China (CMONOC) recorded the crustal movement of Chinese mainland before and after the great Kunlun Mountain earthquake of M=8.1 on November 14, 2001, especially the horizontal crustal movement in the western part of China. Based on the datum defined by a group of stable stations with small mutual horizontal displacements for a few years, the time series of horizontal displacements at fiducial stations were obtained. Significant anomalous horizontal displacements had appeared at the fiducial stations in the western part of China since early November 2000 and several earthquakes with the magnitudes about 6.0 had occurred in Yunnan and Sichuan Provinces. The northward components of the horizontal displacement at the fiducial stations in west China had decreased significantly and even changed in the opposite sense since mid April 2001. After the earthquake, the northward displacements still decreased and there were significant westward displacements. The process of the crustal movement in the western part of Chinese mainland (in reference to east China) suggests that the main force source for this earthquake came from the northward pushing of the Indian plate. The great earthquake released a large amount of energy, as a result, the action applied by the Indian plate to Chinese mainland diminished significantly and after the great earthquake, the seismic activity in Chinese mainland decreased considerably until the end of 2002. Foundation item: The National Development and Programming Project for Key Basic Research (95-13-03-07).     

Horizontal crustal movement in Chinese mainland from 1999 to 2001

The paper introduces the horizontal crustal movement obtained from GPS observations in the regional networks (including the basic network and the fiducial network) of the Crustal Movement Observation Network of China (CMONOC) carried out in 1999 and 2001. This paper is characterized by the acquisition of the horizontal displacement velocities during the period from 1999 to 2001 at the observation stations in the regional networks with datum definition of a group of stable stations with small mutual displacements in east China. Based on the most detailed map of horizontal crustal movement in Chinese mainland, the division of blocks, their displacements and deformations are studied. An approach to analysis of the intensity of the horizontal crustal deformation is proposed. The general characteristics of the recent horizontal crustal movement in Chinese mainland and that before the Kunlunshan earthquake of M=8.1 on November 14, 2001 are analyzed. Foundation item: The National Development and Programming Project for Key Basic Research (95-13-03-07).     

Crustal Movement Observed by GPS and Earthquake Activity in the Chinese Mainland and its Neighborhood

The general characteristics of the recent horizontal crustal movement in the Chinese Mainland and the horizontal crustal movements before the Kunlun Mountain earthquake of M8.1 on Nov. 14, 2001 and two earthquakes of M 8.0 and M 7.9 occurred in Sept. 2003 around the Chinese Mainland are analyzed with GPS data obtained in the Crustal Movement Observation Network of China (CMONOC). Relative vertical displacements observed in the last five years at fiducial stations show that there was a significant correlation between the length of day and the vertical displacements at most stations in western China.     

General characteristics of the recent horizontal crustal movement in Chinese mainland

1 Introduction of GPS observation dataThe Crustal Movement Observation Network of China (CMONOC) is a major scientific project in China organized by China Seismological Bureau and paticipated by the Bureau of Surveying and Mapping of the General Staff, the Chinese Academy of Sciences and the National Bureau of Surveying and Mapping. Based on the observation data of 25 fiducial stations and 56 basic stations in CMONOC (Figure 1 and Table 1), collected from August 26 to September…     

中国大陆GPS连续观测站测得的日本9.0级地震同震位移与震前变化

利用中国大陆GPS连续观测站资料, 获取了2011年3月11日日本9.0级地震造成的连续站同震位移。 计算结果表明, 位于我国东部尤其是东北地区的台站在水平方向都有明显的同震位移, 且离震中越近同震位移量越大, 其中绥阳站的水平同震位移量最大, 达到33 mm。 通过对时间序列分析发现, 有明显同震位移的连续站, 震前水平方向的运动速度都有放缓的趋势, 可能是一种形变前兆现象。 这些GPS观测到的同震位移及震前运动速度异常, 对于进一步研究前兆地壳运动、 地震动力学特征以及精化中国大陆地壳运动速度场都有重要意义。