Temporal change of the earth’s inner core from repeating earthquakes

Inner core;Repeating earthquakes

Yang, Yi ; Song ; Xiaodong

关键词: Inner core;    Repeating earthquakes;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/97624/YANG-THESIS-2017.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The differential motion, lateral velocity gradient, and topography of the Earth’s inner core make the temporal change of the core phases’ arrival times observable in waveform doublets, a pair of events happened at the same location and recorded by the same stations. Using doublets searched from the events in the South Sandwich Island (SSI) region recorded by the station COLA, we observed systematic temporal variations and recalculated the inner core’s differential spin rate relative to the mantle as 0.2-0.4 degree/yr, which is slightly smaller than that estimated by previous study of Zhang et al. (2005). We also analyzed the topography of the inner core boundary (ICB) beneath Africa with the doublets recorded by seismic stations in Asia. There are obvious temporal changes of the ICB, which may indicate the melting and freezing of the ICB in recent decades.