Recent surface displacements in the Upper Rhine Graben — Preliminary results from geodetic networks
Recent surface displacements in the Upper Rhine Graben — Preliminary results from geodetic networks
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DOI：
10.1016/j.tecto.2012.10.012
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发表时间：
2013-08
期刊：
影响因子：
2.9
通讯作者：
T. Fuhrmann;B. Heck;A. Knöpfler;F. Masson;M. Mayer;P. Ulrich;M. Westerhaus;K. Zippelt
中科院分区：
文献类型：
--
作者：
T. Fuhrmann;B. Heck;A. Knöpfler;F. Masson;M. Mayer;P. Ulrich;M. Westerhaus;K. Zippelt
利用GNSS上莱茵地堑网（GURN）和德国、法国和瑞士的国家水准测量网的数据集，对上莱茵地堑（URG）地区的当前地表位移进行了研究。GURN由大约80个永久的全球卫星导航系统（GNSS）站组成。地面水准网包括一级和二级水准线，从1922年开始，每隔大约25年重新测量一次。与早期的研究相比，国家机构和私营公司提供了原始数据，从而为URG地区提供了一致的解决方案。我们把重点放在了调查区域的南部和东部。我们的初步结果表明，水准和GNSS数据集对小的地表位移率分别敏感到0.2 mm/a和0.4 mm/a数量级。从GNSS坐标时间序列中获得的斯特拉斯堡以南试验区观测到的水平速度分量变化约为0.5 mm/a。结果与左旋走滑构造的地震间应变基本一致。由于GNSS导出的垂直分量精度不足，因此使用精密水准网的数据来确定垂直位移率。在URG东部，一级水准线的运动调整得到的垂直速率在- 0.2 mm/a和+ 0.2 mm/a之间，超过75%，表明该区域表现稳定。在Freiburg南部的有限地区，较高的速率高达0.5 mm/a，这与活动断层大致一致。我们的结论是，这两个网络都提供了稳定的结果，反映了URG区域的真实地表运动。然而，我们注意到，测地观测到的地表位移通常是不同影响的叠加，构造和非构造过程的分离需要额外的信息和专业知识。
Datasets of the GNSS Upper Rhine Graben Network (GURN) and the national levelling networks in Germany, France and Switzerland are investigated with respect to current surface displacements in the Upper Rhine Graben (URG) area. GURN consists of about 80 permanent GNSS (Global Navigation Satellite Systems) stations. The terrestrial levelling network comprises 1st and 2nd order levelling lines that have been remeasured at intervals of roughly 25 years, starting in 1922. Compared to earlier studies national institutions and private companies made available raw data, allowing for consistent solutions for the URG region. We focussed on the southern and eastern parts of the investigation area. Our preliminary results show that the levelling and GNSS datasets are sensitive to resolve small surface displacement rates down to an order of magnitude of 0.2 mm/a and 0.4 mm/a, respectively. The observed horizontal velocity components for a test region south of Strasbourg, obtained from GNSS coordinate time series, vary around 0.5 mm/a. The results are in general agreement with interseismic strain built-up in a sinistral strike–slip regime. Since the accuracy of the GNSS derived vertical component is insufficient, data of precise levelling networks is used to determine vertical displacement rates. More than 75% of the vertical rates obtained from a kinematic adjustment of 1st order levelling lines in the eastern part of URG vary between − 0.2 mm/a and + 0.2 mm/a, indicating that this region behaves stable. Higher rates up to 0.5 mm/a in a limited region south of Freiburg are in general agreement with active faulting. We conclude that both networks deliver stable results that reflect real surface movements in the URG area. We note, however, that geodetically observed surface displacements generally result from a superposition of different effects, and that a separation in tectonic and non-tectonic processes needs additional information and expertise.