• ISSN 2097-1893
  • CN 10-1855/P

短周期密集台阵深部地壳结构探测研究进展

Research progress of short period dense nodal array in deep crustal structure exploration

  • 摘要: 由于穿透能力强,天然地震接收函数成为壳幔结构探测中最为广泛使用的方法. 随着人们对地球内部结构和动力学过程认识程度的提高,台间距相对较大的宽频带台阵已无法满足壳幔结构高分辨率探测的需求. 短周期密集台阵采用频率较高的便携式数字地震仪,通过百米级台间距的密集观测,可在短时间内(1~2个月)获得大量地震数据. 其优势主要表现在三个方面:(1)地壳内射线交叉覆盖好,有利于提高分辨率;(2)射线密集分布,通过相干叠加压制噪声,可实现高频接收函数的成像;(3)观测时间短,效率高. 因此,短短几年内,短周期密集台阵已经成为地壳深部结构探测的常规手段之一. 本文主要介绍短周期密集台阵深部地壳结构探测的由来,以及通过几个典型的探测实例,展示探测效果及其在不同构造域的应用.

     

    Abstract: Because of its strong penetrating capability, the natural seismic receiving function has become the most widely used method for detecting crust-mantle structure. As the understanding of the structure and dynamic processes in the crust and upper mantle has advanced, the broadband seismic array with relatively large station spacing has become incompetent to the high-resolution imaging. The Dense Nodal Seismic Array (DNA), composed of hundreds of short-period portable digital high-frequency seismometers, offers a solution with station spacing as small as a few hundred meters, allowing for the collection of substantial observational data in a short time (1-2 months). Its advantages mainly include three aspects: (1) Good cross-ray-path coverage in the crust, conducive to improving imaging resolution; (2) Densely distributed ray-paths, facilitating noise suppression through coherent stacking of receiver functions, allowing for high-frequency receiver function imaging of crustal structures; (3) High efficiency due to the short observation time. Therefore, short-period dense array has become one of seismic observation approach commonly adopted in deep crustal structure research for only a few years. This paper mainly introduces the origin of short-period dense array in deep crustal structure exploration, and demonstrates its exploration effect and application in different tectonic domains through several typical exploration examples.

     

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