Abstract: In order to investigate the present-day movement characteristics of Haiyuan active fault zone and Xiangshan-Tianjingshan active fault zone on the northeast margin of Tibetan Plateau in detail, we established a GPS profile across the fault zones. The profile, extending from Lanzhou, Gansu to Zhongwei, Ningxia, is composed of 12 stations and locally reinforced the existing regional GPS network of Crustal Movement Observation Network of China (CMONOC). These new stations, together with the existing GPS stations, constructed a spatially dense profile whose average interval of the stauions is ~22km. Considering that there were two continuous GPS stations of CMONOC (i.e. XNIN and YANG) around the region, we tried a “Flexible Observation Method” in GPS observations. The method allows non-synchronal observations for all the GPS observation teams and makes the observation schedule rather flexible. In data processing, we used the advanced strategy of “Precise Point Positioning” of GIPSY software. Our result shows that with the support of CMONOC, especially the continuously observed fiducial GPS network of CMONOC, we can use the “Flexible Observation Method” and “Precise Point Positioning” data processing strategy to effectively observe local GPS networks to monitor crustal deformation with satisfying accuracy.

Key words: crustal deformation, GPS observation, data processing, Tibetan Plateau

摘要： 为了对青藏高原东北缘海原断裂带和香山-天景山断裂带的现今走滑及逆冲运动状况进行更加精细的观测研究,我们沿甘肃兰州至宁夏中卫一线布设了1条由12个站点构成的跨断裂GPS加密测线网。该测线网的站点在空间分布上与“中国地壳运动观测网络”的已有站点相互补充,共同构成了1条平均点距约22km的密集型GPS跨断裂剖面。在第1期观测中,考虑到测区周围存在2个“中国地壳运动观测网络”的连续观测基准站(西宁XNIN、盐池YANC),我们尝试采用了各观测组未必同步的“自由观测方式”,而在数据处理中采用了GIPSY先进的“精确单点定位”策略。结果表明,由“中国地壳运动观测网络”的连续基准网作为支撑平台,在局部区域的GPS加密监测中采用灵活的“自由观测方式”和简易的“精确单点定位”数据处理策略,能够在满足精度要求的前提下更加有效地实施。

关键词: 地壳形变, GPS观测, 数据处理, 青藏高原