高源, 瞿伟, 张勤, 王庆良, 郝明. GNSS揭示的汾渭盆地及周缘现今地壳运动与应变差异[J]. 武汉大学学报 ( 信息科学版), 2021, 46(7): 1063-1070. DOI: 10.13203/j.whugis20190365
引用本文: 高源, 瞿伟, 张勤, 王庆良, 郝明. GNSS揭示的汾渭盆地及周缘现今地壳运动与应变差异[J]. 武汉大学学报 ( 信息科学版), 2021, 46(7): 1063-1070. DOI: 10.13203/j.whugis20190365
GAO Yuan, QU Wei, ZHANG Qin, WANG Qingliang, HAO Ming. Differential Characteristics of Present-Day Crustal Movement and Strain Field in the Fenwei Basin and Its Surrounding Regions Revealed by GNSS Observations[J]. Geomatics and Information Science of Wuhan University, 2021, 46(7): 1063-1070. DOI: 10.13203/j.whugis20190365
Citation: GAO Yuan, QU Wei, ZHANG Qin, WANG Qingliang, HAO Ming. Differential Characteristics of Present-Day Crustal Movement and Strain Field in the Fenwei Basin and Its Surrounding Regions Revealed by GNSS Observations[J]. Geomatics and Information Science of Wuhan University, 2021, 46(7): 1063-1070. DOI: 10.13203/j.whugis20190365

GNSS揭示的汾渭盆地及周缘现今地壳运动与应变差异

Differential Characteristics of Present-Day Crustal Movement and Strain Field in the Fenwei Basin and Its Surrounding Regions Revealed by GNSS Observations

  • 摘要: 利用汾渭盆地及周缘地块2011—2017年高精度GNSS (global navigation satellite system)监测资料,分析了区域现今地壳运动差异性与形变特征,并基于球面最小二乘配置法构建了区域运动变形模型,反演获得了区域应变场,定量解译了不同区块间的应变差异特征。结果表明,区域地块间现今拉张或压缩速度约为1~2 mm/a; 区域整体表现出北西-南东向拉张应变特征,且典型域应变剖面定量揭示出汾渭盆地在周边地块差异性变形中的“调节带”作用; 2008年汶川地震与2011年日本宫城地震后,汾渭盆地的地震活动率在短时期内有所下降,且最大剪应变呈减小趋势,其原因可能与同震及震后效应减缓区域的应变积累有关。

     

    Abstract:
      Objectives  The Fenwei Basin is characterized by numerous tectonic faults, with the occurrence of many devastating earthquakes. Quantitatively studying the deformation difference between the Fenwei Basin and its adjacent blocks, and the impact of 2008 Wenchuan and 2011 Tohoku earthquakes will extend our understanding of present crustal movement characteristics of this region.
      Methods  We first used high precision global navigation satellite system (GNSS) velocities ranging from 2011 to 2017 to study the tectonic movement and relative activities of faults. Then the strain results were obtained by constructing a kinetic model using spherical least square collocation method to interpret differential strain characteristics among several blocks, followed by discussing the influence of different reference frames. Finally, the impact on deformation and seismic activities of neighboring large earthquakes was investigated by using both strain results and earthquake catalog.
      Results  (1) The Fenwei Basin and its neighboring blocks moves to SEE direction with reference to the stable Eurasian Plate, with the magnitude of approximate 5.18 mm/a and 1.54 mm/a in east and north components, respectively. Relative crustal motion rate between different blocks was approximate 1-2 mm/a. (2) The whole area exhibited NW-SE oriented principal extensional strain and the role of accommodation zone that the Fenwei Basin plays in differential movement within peripheral blocks was well revealed by typical domain profile results. (3) The maximum shear strain rate decreased after the Wenchuan and Tohoku earthquakes, and the seismic activities dropped after the Tohoku earthquake.
      Conclusions  Our study suggested notable deformation differences between the Fenwei Basin and its adjacent blocks. The tectonic strain accumulation process in the Fenwei Basin decelerated due to co-seismic and post-seismic effect of the two great earthquakes.

     

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