Imaging of Deep Planetary Interiors from Inter-source Correlations via a Single Seismograph

Global seismic imaging of the Earth's interior has come a long way in exploring and understanding the Earth’s internal structure and dynamics with the worldwide proliferation of seismographs. However, investigating planetary interiors, including detections of their deep structures, remains challenging because of the limited number of seismographs that are and will be deployed in the foreseeable future. Besides, the existing imaging methods based on observations of a direct seismic wavefield from seismic sources require the emergence of the seismic waves with distinguishable amplitudes. That condition restricts the seismic station locations for practical wave reflections or refractions from internal planetary interfaces to a limited angular distance range from the source.

Here, we explore a new way to image deep planetary interiors, especially the planetary cores, using a single seismograph. We first develop a novel procedure for constructing global inter-source correlograms and show that they contain many prominent features sensitive to the internal planetary structures. We demonstrate that a single station is sufficient to produce a global correlogram for the Earth. We then utilize a single-station correlogram and show the steps for detecting and quantifying the Earth’s and Martian cores interfaces. This provides a new paradigm for imaging deep planetary interiors on global scales.