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地震 ›› 2025, Vol. 45 ›› Issue (3): 31-53.doi: 10.12196/j.issn.1000-3274.2025.03.003

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川滇块体中部岩石圈分层各向异性

杨逸文1, 高原1, 李心怡1,2   

  1. 1.中国地震局地震预测研究所(地震预测重点实验室), 北京 100036;
    2.中国地震局地球物理研究所, 北京 100081
  • 收稿日期:2024-12-10 修回日期:2025-02-19 出版日期:2025-07-31 发布日期:2025-10-23
  • 通讯作者: 高原, 研究员。 E-mail: qzgyseis@163.com
  • 作者简介:杨逸文(1999-), 女, 浙江温州人, 在读硕士研究生, 主要从事地震学研究。 E-mail: yangyw1013@163.com
  • 基金资助:
    国家自然科学基金重点项目(42330311); 中国地震局地震预测研究所基本科研业务费专项(CEAIEF20230301)

Lithospheric Layered Anisotropy in the Middle Part of Sichuan-Yunnan Block

YANG Yi-wen1, GAO Yuan1, LI Xin-yi1,2   

  1. 1. Key Laboratory of Earthquake Prediction, Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China;
    2. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
  • Received:2024-12-10 Revised:2025-02-19 Online:2025-07-31 Published:2025-10-23

摘要: 二级川滇块体地处青藏高原物质侧向挤出与一级华南块体接触的前缘地带, 受不同活动性质的边界断裂强烈控制, 构造运动和地震活动强烈。 川滇块体中部的丽江—小金河断裂和锦屏山断裂(统称为广义的丽江—小金河断裂)将川滇块体划分为川西北和滇中两个活动强度差异显著的次级块体。 断裂沿线地震活动多发, 其区域岩石圈结构与深部变形是青藏高原周缘岩石圈变形及侧向生长机制的重要科学问题。 地震各向异性在地球内部的广泛存在是理解岩石圈结构和变形的关键。 本文结合区域断裂分布、 地震活动、 地表变形、 应力场分布及深部结构特征, 通过对比近震S波分裂、 远震接收函数和远震SKS系列震相的S波分裂方法得到的各向异性特征, 综合体波、 面波及全波形各向异性层析成像结果, 获得不同深度和尺度的深部变形分布特征。 基于上地壳、 全地壳及岩石圈的变形特征分析, 探讨川滇块体中部的分层各向异性与变形耦合机制, 为深化青藏高原及其周缘地区演化机制和深部过程研究提供科学依据。

关键词: 川滇块体中部, 分层各向异性, S波分裂, 接收函数, 速度结构

Abstract: The Sichuan-Yunnan secondary block is located in the forefront of the lateral extrusion of material from the Qinghai-Xizang Plateau and the contact with the South China primary block. It is strongly influenced by boundary faults of different activity characteristics, resulting in intense tectonic movements and seismic activity. Lijiang-Xiaojinhe fault and Jinpingshan fault (collectively referred to as the generalized Lijiang-Xiaojinhe fault system) within the middle of Sichuan-Yunnan block divide Sichuan-Yunnan block into two sub-blocks: northwestern Sichuan block and central Yunnan block, which exhibit distinct differences in tectonic activity intensity levels. Seismic activity along these faults is intense, and the regional lithospheric structure and deep deformation characteristics are critical scientific issues for understanding the lithospheric deformation and lateral growth mechanisms around the margins of the Qinghai-Xizang Plateau. The widespread existence of seismic anisotropy within the earth's interior is the key to accurately interpreting lithospheric structures and deformation. In this paper, based on the faults distribution, seismic activity, ground deformation, stress distribution and deep structures in the region, the deep deformation distribution with different depths and scales is obtained by comparing the anisotropic characteristics derived from S-wave splitting method for near-field earthquakes and teleseismic SKS series phases, and the anisotropic tomography results from composite waves, surface waves and full waveforms. Through analysis of deformation characteristics in the upper crust, entire crust and the lithosphere (including the middle and lower crust and the upper mantle), this study discusses the layered anisotropy and deformation coupled characteristics in the middle part of Sichuan-Yunnan block. These findings provide scientific references for further research into the evolution mechanisms and deep processes of the Qinghai-Xizang Plateau and its surrounding regions.

Key words: Middle part of Sichuan-Yunnan block, Layered anisotropy, S-wave splitting, Receiver function, Velocity structure

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