Gravity variation before Kunlun mountain pass western Ms=8.1 earthquake     

祝意青王双绪  江在森朱桂芝李辉  张永志 《地震学报(英文版)》2003,16(3):304-311

The relation between the gravity variation features and Ms=8.1 earthquake in Qinghai-Xizang monitoring area is analyzed preliminarily,by using spatial dynamic variation results of regional gravity field from absolute gravity and relative gravity observation in 1998 and 2000.The results show that:1)Ms\8.1 earthquake in Kulun mountain pass westem occurred in the gravity variation high gradient near gravity‘s high negative variation;2)The Main tectonic deformation and emnergy accumulation before MS=8.1 earthquake are distributed at south side of the epicenter;3)The range of gravity‘s high negative variation at east of the MS=8.1 earthquake epicenter relatively coincides with that rupture region according to field geology investigation;4)Gravity variation distribution in high negative value region is just consistent with the second shear strain‘s high value region of strain field obtained from GPS observation.  相似文献   

Continuous wavelet-like filter for a spherical surface and its application to localized admittance function on Mars     

Motoyuki Kido  David A. Yuen 《Physics of the Earth and Planetary Interiors》2003,135(1):1-16

We have developed a 2D isotropic continuous wavelet-like transform for a spherical surface. The transform is simply defined as the surface convolution between the original field and a kernel, based on the zeroth-order Bessel function with a spherical correction. This spherical correction violates the geometric similarity for the various scales of the kernels, which becomes more apparent at longer wavelengths. We found numerically that this transform is practically equivalent to a Gaussian bandpass filter in the spherical harmonic domain. We have applied this wavelet-like transform on the recently acquired Martian gravity and topography fields. Using a ratio constructed locally from these two fields, we have constructed a map describing the lateral variations of the localized admittance function on Mars.  相似文献   

The role of sediment specific gravity and availability on cluster evolution     

A. N. Papanicolaou  K. Strom  A. Schuyler  N. Talebbeydokhti 《地球表面变化过程与地形》2003,28(1):69-86

The objective of this experimental study was to account for the role of sediment availability and specific gravity on cluster formation and cluster geometric characteristics (spacing and size). To isolate the effects of sediment availability and specific gravity on cluster evolution, mono‐sized spheres were used to simulate the cluster evolutionary cycle. Overall, twelve experimental runs were carried out in the laboratory flume. Six of these tests were performed by using glass spheres (specific gravity, SG = 2·58) and the other six by employing an equal combination of glass and Teflon spheres (SG = 2·12) of the same diameter to evaluate the role of specific gravity on cluster evolution. The three sediment availability conditions that were investigated here simulated isolated gravel elements, pool–riffle sequences and densely packed gravel‐bed. An advanced image analysis technique was employed to track the evolution of cluster microforms and provide quantitative information about the size and shape of clusters and the number of clusters per unit area. The results of this study showed that: (1) sediment availability affects the architecture and size of cluster microforms; and (2) clusters consisting of mono‐sized sediments start disintegrating at twice the incipient conditions. By performing complementary tests for the isolated gravel elements case, it was found that the evolutionary cycle of individual clusters could be described as follows, in order of increasing stress: no cluster→two particle cluster→comet→triangle→rhomboid→break up. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

高精度推求正高的两种方法     

张赤军 《武汉大学学报(信息科学版)》2003,28(4):432-434,443

论述了高精度推求正高的两种方法 ,并对正高精度的推估及其在模型上的试算也作了讨论 ,对于海拔为 5 0 0 0m的高山 ,正高的误差一般不超过± 1 0cm ,这与距青岛水准原点达数千公里的西部高山 (原 )处正常高的精度也比较接近  相似文献   

深圳市1 km高分辨率厘米级高精度大地水准面的确定   总被引：56，自引：1，他引：56  

宁津生  罗志才  杨沾吉  陈永奇  张天纪 《测绘学报》2003,32(2):102-107

利用65个精度优于2 cm的GPS水准数据、5 213个实测重力点数据、100 m分辨率的数字地形模型和WDM94地球重力场模型,采用移去-恢复技术计算了深圳市1 km分辨率的大地水准面模型.将该模型大地水准面高与由29个GPS水准得到的大地水准面高进行比较,其差值的标准差为±1.4 cm.  相似文献   

利用卫星测高空间技术建立数字化海洋     

彭富清  张瑞华  石磐  夏哲仁  程芦颖 《测绘工程》2003,12(1):37-40

论述了卫星测高空间技术的主要特征、科学意义及其在军事和经济建设领域的重要价值，阐明了国内外测高卫星系统的发展现状及利用卫星测高空间技术建立数字化海洋所取得的成果，分析卫星测高目前的研究方向，提出了发展我国卫星测高空间技术以及利用该技术建立数字化海洋的一些建议。  相似文献   

建设我国现代大地测量基准的思考   总被引：7，自引：0，他引：7  

陈俊勇 《武汉大学学报(信息科学版)》2003,(Z1)

建设现代大地测量基准方面的进展主要表现在IGS服务和ITRF的系列精化 ,ITRF2 0 0 0是ITRF中迄今最为精确、测站最为稠密的地面坐标参考框架 ;2 0 0 1年推出新的WGS84,其成果标以WGS84(G1 1 5 0 )。考虑和顾及现代大地测量的特点 ,结合中国实际 ,我国现代大地测量基准应着重考虑四个方面的基本要素 :高精度、涵盖全部陆海国土、三维、动态。建设我国现代大地测量基准是为用户在我国任何地点、任何时间提供及时、可靠、适用的地理空间基础框架 ,其任务应包括建立我国现代化的平面基准、高程基准和重力基准等。  相似文献   

论我国大地测量基础建设   总被引：2，自引：1，他引：2  

魏子卿 《武汉大学学报(信息科学版)》2003,(Z1)

概述了我国大地控制网、高程控制网和地球重力场等基础建设的基本情况、需求分析与任务建议。提出我国空间大地网应由连续运行参考站、一级网、二级网和三级网组成 ;一、二等水准网复测和高程基准再定义 ;为精化大地水准面 ,要补测重力点和加测GPS/水准点。  相似文献   

扰动重力边值问题与实际数据处理的研究   总被引：3，自引：0，他引：3  

吴晓平  李姗姗  张传定 《武汉大学学报(信息科学版)》2003,(Z1)

讨论了应用GPS测量重力点的大地高 ,从而获得地面点的扰动重力 (或称纯重力异常 )值这样新的重力边值条件 ,如何从理论与实际上确定重力场的问题。  相似文献   

国家地理空间信息基准框架工程建设     

张燕平  张全德  张江齐  岳建利 《武汉大学学报(信息科学版)》2003,(Z1)

提出了国家地理空间信息基准框架内改进与更新原有的大地坐标基准、高程基准和重力基准的建设道路及解决原则。  相似文献