根据海底地震数据估计的马里亚纳海域的水输入量
Chen Cai1, Douglas A Wiens2, Weisen Shen2,3
1Department of Earth and Planetary Sciences, Washington University in St Louis, St Louis, MO, USA. cai.chen@wustl.edu.
Nature
|November 16, 2018
概括
下降带将水输送到地球的深处,但此前对这种水流的估计是不确定的. 新的地震数据揭示了比以前想象的更多的水位, 修改了全球估计.
科学领域:
- 地质学
- 地球科学
- 地震学
背景情况:
- 地球深层水循环的理解很少,在潜水区的水流估计中存在显著的不确定性.
- 之前的地震研究表明,沉积板块中的水分,但缺乏深度约束,特别是在较旧的板块中.
研究的目的:
- 使用地震数据调查玛丽亚纳海沟下地幔水分的程度.
- 为了精确地估计地球地幔中的水沉降.
主要方法:
- 来自海洋底地震数据的雷利波分散的分析.
- 在马里亚纳海沟周围的地和上层地幔的地震图像生成.
主要成果:
- 地震图像显示地幔的水分扩展在莫霍断层下方大约24公里.
- 据估计,该地区的降水量至少是此前估计的4.3倍.
- 全球水流估计到地幔 (>100公里深度) 可能需要增加三倍.
结论:
- 旧的冷板可能比以前估计的含水量大得多.
- 修订后的估计影响了我们对地球深层水循环的理解.
- 在火山弧和背弧盆地上升的水排放可能是必要的.
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