利用光谱特征区分构造、群集和与撞击相关的火星地震
Discrimination of Tectonic, Swarm and Impact-related Marsquakes using Spectral Characteristics
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中文总结 AI 辅助
该研究利用光谱特征对火星地震进行分析，提出基于源过程等的框架描述其光谱特征，能为地震分配相关测量值并获特征模式，可将地震目录分为三类，还判断出最大火星地震S1222a可能属陨石撞击类。
中文摘要 AI 辅助
美国国家航空航天局的洞察号任务在其三年任务期间观测到2000多次火星地震。这些地震震级在1.5到4.5之间，光谱内容也各不相同。我们提出了一个简单框架，基于源过程、在地幔或地壳中的传播以及局部接收端放大来描述所有观测到的火星地震的光谱特征。为每次地震分配其振幅的客观测量值，以及由破裂持续时间和粘弹性衰减导致的高频衰减所产生的光谱衰减。这使我们能够获得整个火星地震数据集的特征模式。我们发现很大一部分火星地震——高频地震——形成了一个群集，可能不是由岩石中的构造过程引起的。我们的分析可将整个火星地震目录分为构造地震、陨石撞击和群集事件三类。最后我们得出结论，最大的火星地震S1222a很可能属于陨石撞击类别。
英文摘要
The NASA InSight mission observed over 2000 marsquakes in the course of its three year mission. These quakes varied in magnitude between 1.5 and 4.5, as well as in spectral content. We present a simple framework to describe the spectral characteristics of all observed marsquakes, based on source process; propagation through the mantle or crust; and local, receiver-side amplification. We assign to each quake an objective measure of its amplitude, as well as the spectral decay created by the duration of the rupture and the dampening of high frequencies due to visco-elastic attenuation. Together, this allows us to obtain characteristic patterns of the whole marsquake dataset, e.g. in terms of event magnitudes, source size, and - for quakes caused by meteoritic impacts - crater size. We show that a significant fraction of all marsquakes - the high-frequency quakes - form a swarm that is likely not caused by tectonic processes in rocks. Our analysis allows separation of the whole marsquake catalogue into three event classes, of tectonic quakes, meteoritic impacts, and swarm events. We finally conclude that the largest marsquake, S1222a, most likely belongs to the group of meteoritic impacts.
