深度地震的后地震变形显示的薄弱的上层地幔底部
Sunyoung Park1, Jean-Philippe Avouac2, Zhongwen Zhan2
1Department of the Geophysical Sciences, The University of Chicago, Chicago, IL, USA. sunnypark@uchicago.edu.
Nature
|February 22, 2023
概括
研究人员使用2018年斐济地震的地震后变形数据在地幔过渡区底部确定了一层薄而低粘度的层. 这种弱势区域有助于解释地质现象,比如沉积区的石板平面化.
科学领域:
- 地质学
- 地球科学
- 地震学
背景情况:
- 地幔粘度对于地球的内部动态和热进化至关重要.
- 之前的地质研究显示了地幔粘度推断的显著变化.
- 了解地幔粘度是解释大规模地质过程的关键.
研究的目的:
- 使用地震后变形数据调查地幔粘度结构.
- 分析地震对周围地幔的影响.
- 改进地球内部结构和动态的模型.
主要方法:
- 利用地质时间序列的独立组件分析来提取地震后变形信号.
- 应用前方粘弹性放松模型来测试各种粘度结构.
- 专注于2018年斐济8.2级地震的数据.
主要成果:
- 成功检测并提取来自斐济地震的地震后变形.
- 确定了对薄的要求 (约. 在地幔过渡区底部的低粘度层 (10^1710^18 Pa·s).
- 该模型解释了以前具有挑战性的观测,如板块平整和孤儿.
结论:
- 推断的低粘度层可能是由超塑性,弱矿,高含水量或脱水溶解引起的.
- 这一发现提供了对地幔过渡区的新见解.
- 这项研究为潜伏区观察到的关键特征提供了潜在的解释.
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