由于一次对小行星433 Eros的撞击,地震重新浮出水面
1Center for Radiophysics and Space Research, Cornell University, Ithaca, New York 14853, USA. thomas@baritone.astro.cornell.edu
Nature
|July 22, 2005
概括
对小行星Eros的冲击可以通过地震波擦除较小的石坑,而不仅仅是喷射. 这一发现揭示了地震能量如何塑造小型物体表面和火山口群体.
科学领域:
- * 星球科学 星球科学
- * * 小体地质学
- * * 撞击坑的动力学
背景情况:
- *撞击坑是塑造小卫星和小行星表面的主要过程.
- *小行星433 Eros在其表面呈现出无法解释的火山口密度变化.
- * 了解火山口演变对于小体地质学至关重要,因为没有内源性过程.
研究的目的:
- * 调查小行星433 Eros上的不明原因火山口密度变化背后的机制.
- * 确定更年轻,更大的石坑如何影响小物体上现有的石坑群.
- * 分析地震能量与喷射物埋葬在火山口移除中的作用.
主要方法:
- * 分析小行星433 Eros上的坑群和密度.
- *模拟大型撞击事件 (7.6公里长的石坑) 对周围地形的影响.
- * 观察到的坑移除模式与喷射物埋葬和地震退化模型的预测进行比较.
主要成果:
- * 埃罗斯上的7.6公里长的石坑在小行星表面的40%左右移除了较小的石坑 (长达0.5公里).
- * 坑道移除模式与喷射物埋葬不一致,这表明了另一个替代机制.
- * 减少的火山口密度仅限于与撞击地点相关的特定区域,表明地震能量传播.
结论:
- *大冲击期间释放的地震能量显著降低了地形,并消除了小行星上的较小石坑.
- *埃罗斯的内部足够凝聚力,可以在几公里外传输地震能量.
- * 埃罗斯的外层 (几十米) 由相对不凝聚的材料组成,易受地震破坏.
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