用中国资料进一步约束地球最内核的各向异性

Anisotropy of the Innermost Inner Core Further Constrained by Chinese Data

基于中国地震台网记录的发生于南美的4个地震事件数据,利用穿过内核并在内外核边界反射的PKIIKP波与直接穿过内核的PKIKP波的到时差,研究地球最内核的速度结构。通过比较PKIIKP-PKIKP波的观测到时差与理论到时差,进一步确认地球最内核的慢轴并不是沿着赤道平面,而是与赤道平面呈一定夹角,为地球内核物理性质和结构研究提供了新的证据。

Relative arrival time difference of two core phases PKIIKP-PKIKP was used to constrain the structure of the Earth＇s innermost inner core. The seismic data＇s epicentral distance is more than 175 degrees from South America earthquake events and recorded by the CEA stations, which can clearly pick the PKIIKP and PKIKP phases. Observation data were stacked for high SNR and then were used to measure arrival time differences between PKIIKP and PKIKP, which were compared with theoretically computed results from PREM afterwards. Results further confirm that the slowest P-wave propagation direction of the innermost inner core is not along the equatorial plane, but forming an angle with it, which provide new constraints on inner core property..