Application of the Seismic Interferometry Method to Study the Earth’s Inner Core

Abstract—Seismic interferometry method is used to extract detailed information about the dynamic processes and the properties of the inner core regions inaccessible to study by traditional methods. The method is based on cross-correlation time series analysis and applied to different data types. Cross-correlation analysis of seismic coda time window with a beginning three hours after a strong event and an end ten hours later is conducted for all possible pairs of more than 300 stations and six large earthquakes (for each separately) that occurred between 2013 and 2024. Synthetic cross-correlograms are calculated for models with different attenuation and an additional boundary in the inner core. Four different types of seismic interferometry analysis of the inner core have been carried out: global, regional, station latitude-dependent and calendar time-dependent. The study has demonstrated the stability of the PKIKPPKIKP wave on global correlograms, the possibility of its observation in regions with high and low density coverage by seismic stations, the dependence of the wave traveltime on the angle between the wave propagation direction and the Earth rotation axis, and the stationarity of the wave over a period from 2013 to 2024.