火星表面的波浪和地结构
D Kim1,2, W B Banerdt3, S Ceylan1
1Institute of Geophysics, ETH Zürich, Zürich, Switzerland.
概括
火星石撞击的表面波显示出不同的地结构. 在赤道二分法以北的地比在InSight着陆器下面的地密度更高,变化更小.
科学领域:
- 星球科学
- 地震学
- 地质学
背景情况:
- 了解火星的地结构对于解读它的形成和演变至关重要.
- 之前的火星地震研究主要集中在InSight着陆器下面的区域.
研究的目的:
- 在远离InSight着陆器的火星地结构上使用地震波.
- 确定剪切波速度的变化,并推断密度和多孔性等属性.
主要方法:
- 探测和分析火星上两颗石撞击产生的地表地震波.
- 测量从撞击地点到InSight着陆器的路径上的群体速度分散.
- 扭转地震数据以限制不同深度的剪切波速度结构.
主要成果:
- 在赤道二分法以北的火星地中,剪切波速度 (深度为5-30公里) 约为3.2公里/秒,变化最小.
- 这种地震速度表明地密度较高或孔隙性较低, 相比InSight着陆器下的区域.
- 在InSight着陆器下观察到的分层,低速结构不是火星地的全球特征.
结论:
- 火星地的结构呈现出显著的区域差异,特别是在赤道二分法和InSight着陆地点之间.
- 这些发现挑战了火星地厚度和形成的全球模型,强调了需要更多空间多样化的地震数据.
- 地震表面波分析为探测火星和其他陆地行星的地下结构提供了强大的工具.
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