超低速的Subslab异常被发现并促进了最大的深度地震
Weiwen Chen1,2, Shengji Wei3,4,5, Weitao Wang6
1Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore.
Nature communications
|March 30, 2024
概括
深度M8+地震挑战了对断层机制的理解. 对俄霍茨克海地震的研究揭示了太平洋板块下方浮动的,化的异常,引发了深度地震断裂.
科学领域:
- 地震学 地震学
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
背景情况:
- 深度地震 (大于600公里) 挑战了由于高压和高温导致的地震断层的传统模型.
- 在极深处发起8+ (M8+) 级地震的机制仍然是神秘的.
研究的目的:
- 调查MW 8.3的冲海地震的破裂启动和机制.
- 分析地震数据以了解深度地震过程.
主要方法:
- 分析高频 (高达0.8Hz) 远程地震阵列数据.
- 确定次事件的位置,时间和附近的结构异常.
- 地震速度扰动分析.
主要成果:
- 在太平洋板块下方在660公里不连续性附近发现了一个小规模的 (~30 × 60 × 60公里) 超低P波速度异常 (-18 ± 2%).
- 异常表现出一种挥发性轴承,高度化的组成,赋予浮力和压力板块.
- 这种情况有助于破裂传播到超出转移稳定的奥利文,使M8+事件成为可能.
结论:
- 一个深,浮动和融化的异常可以在以前认为不利于地震滑动的深度引发大地震.
- 这些发现需要进一步研究矿物物理和地力学,以充分理解深层地震的产生.
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