云南南部今天的构造压力演变基于焦点机制
Wenjie Fan1,2, Ye Zhu1,3, Yingfeng Ji1,3
1State Key Laboratory of the Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
Sensors (Basel, Switzerland)
|September 9, 2023
概括
东喜马拉雅山脉附近的构造挤出导致云南南部频繁地震. 这项研究揭示了复杂的地震焦点机制和应力轴的顺时针旋转,受块相互作用的影响.
科学领域:
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
- 地震学 地震学
背景情况:
- 绕过喜马拉雅东部语法的构造挤出增加了中国云南南部的压力不稳定性和地震频率.
- 在这个地区,精确的应力场和地震焦点机制的演变仍然不太清楚.
研究的目的:
- 为了确定云南南部当今的区域构造应力场.
- 分析地震焦点机制与该地区压力演变之间的关系.
主要方法:
- 使用修改的网点测试方法 (2009年1月~2023年6月) 计算地震 (本地级2.5或更大) 的焦点机制.
- 逆转历史地震焦点机制解决方案以获得区域构造应力场.
主要成果:
- 观测到复杂多样化的地震焦点机制,主要是冲击滑动,随后是正常和反向断层事件.
- 确定了最大和最小主要应力轴的顺时针旋转,从东北向西南.
- 在区块边界发现应力偏移,表明区块间相互作用的影响.
结论:
- 云南南部的应力场是由构造块的相互作用形成的,特别是四川-云南块和南中国块.
- 块移动速度的北向南趋势下降,Lamping-Simao块的R值增加,表明压力应力降低.
- 南中国区块的压力较高和R值较小表明挤出更强,可能是由于四川-云南区块的阻力.
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