• ISSN 2097-1893
  • CN 10-1855/P
胡亚轩,赵凌强,庄文泉,梁国经,綦伟. 2023. 基于大地测量和MT技术分析吉林龙岗火山区现今地壳运动特征及其机理. 地球与行星物理论评(中英文),54(6):633-642. doi: 10.19975/j.dqyxx.2022-069
引用本文: 胡亚轩,赵凌强,庄文泉,梁国经,綦伟. 2023. 基于大地测量和MT技术分析吉林龙岗火山区现今地壳运动特征及其机理. 地球与行星物理论评(中英文),54(6):633-642. doi: 10.19975/j.dqyxx.2022-069
Hu Y X, Zhao L Q, Zhuang W Q, Liang G J, Qi W. 2023. Analysis of the crustal movement characteristics and uplift mechanism of Longgang volcanoes, Jilin, based on geodesy and MT technology. Reviews of Geophysics and Planetary Physics, 54(6): 633-642 (in Chinese). doi: 10.19975/j.dqyxx.2022-069
Citation: Hu Y X, Zhao L Q, Zhuang W Q, Liang G J, Qi W. 2023. Analysis of the crustal movement characteristics and uplift mechanism of Longgang volcanoes, Jilin, based on geodesy and MT technology. Reviews of Geophysics and Planetary Physics, 54(6): 633-642 (in Chinese). doi: 10.19975/j.dqyxx.2022-069

基于大地测量和MT技术分析吉林龙岗火山区现今地壳运动特征及其机理

Analysis of the crustal movement characteristics and uplift mechanism of Longgang volcanoes, Jilin, based on geodesy and MT technology

  • 摘要: 位于吉林长白山西麓龙岗山脉中段的龙岗火山群是中国近代主要火山活动区之一. 通过对火山区2010—2020年多期GNSS(Global Navigation Satallite System)观测资料及1970—2010年多个时段的一、二等水准资料进行解算,获取现今三维地壳运动速度场. GNSS获取的水平运动速率从西向东增大,东部主要以拉张运动为主,连续面应变率场结果反映火山区位于膨胀区;一等水准路线长抚线和丹抚线资料显示火山区以垂直上升运动为主,主要速率为0.55~1.83 mm/a,其中抚松—仙人桥—老山队一带为主要隆升区,速率多大于1.0 mm/a;该区域分布丰富的地热资源,也是地震多发地区. 邻近区域的二等水准路线梅通线速率相对较小,为0.23~0.77 mm/a. 结合对99个测点大地电磁数据三维反演得到的火山区深部电性结构:与隆升区对应的中下地壳赋存相对较浅的岩浆系统,电性边界带推测的浑江断裂北向延伸. 断裂附近的低阻体规模最大,向下延伸至地幔尺度. 最浅的低阻体位于最年轻的金龙顶子火山大约10 km以下位置,以上的高阻结构认为是岩浆溢流结束后的后撤和固结. 综合分析认为现今火山区地壳的膨胀隆升、地震活动与幔源物质的上涌、间断性的运移引起断层活动有关.

     

    Abstract: The Longgang volcanic field is one of the most active volcanoes in modern China. It is situated in the central region of the Longgang mountains on the west slopes of Changbaishan in Jilin. The present three-dimensional crustal movement velocity fields in the different periods were obtained by processing Global Navigation Satellite System (GNSS) observations from 2010 to 2020 and data for the leveling profiles from 1970s to 2010s in the area. The horizontal velocities of GNSS stations were larger in the eastern region than in the western regions, indicating that the eastern region is mainly tensile. The results of the continuous surface strain rates showed that a volcanic field is located in the expansion area. The results of the first-order leveling data for the Changfu profile and the Danfu profile showed that the vertical movements were predominantly uplift, with rates of 0.55~1.83 mm/a for most of the sites. The area with relatively higher uplifting rates of more than 1.0 mm/a was Fusong-Xianrenqiao-Laoshandui, which is rich in geothermal resources and prone to earthquakes. At the adjacent area, Meitong, the rates of the second-class leveling profile were relatively small, at 0.23~0.77 mm/a. The deep electrical structure of the volcanic area was obtained through the three-dimensional inversion of 99 broadband magnetotelluric soundings. The clear structures of the low resistivity in the middle and lower crusts corresponded to the uplift area, which is suggested to be a magmatic system. The position of the magma was relatively shallow. The electrical boundary zone at the northeast end of the Hunjiang fault was speculated to be the northern extension of the fault. The low-resistivity body had the largest scale and extended downward to the mantle. The shallowest low-resistivity body was approximately 10 km below the youngest Jinlongdingzi volcano, and the above high-resistivity structure was considered to be the retreat and consolidation magma after the overflow eruption ended. A comprehensive analysis showed that the ongoing inflation, uplift, and seismic activities of the crust in the volcanic area were related to the upwelling of mantle materials and fault movements caused by intermittent magma migration.

     

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