Exploring inner core structure beneath the Pacific Ocean using US Array data

Inner core plays an important role in governing Earth's dynamics. As Earth cools, the inner core grows slowly over time,releasing latent heat and lighter elements which drive convection in the outer core, and thus help power the Earth’s geodynamo. Seismically, the inner core is characterized by complex features; the dominant structures being an east-west asymmetry in seismic velocity and attenuation, and cylindrical anisotropy.

The anisotropy appears weak at the inner core boundary, but stronger at depths; it is unclear how the shallow anisotropic structure relates to the deeper inner core. Linking these layers is important to understand the evolution of the anisotropy over time.The structure of the inner core is not well constrained at depths of 100-200 km beneath the inner core boundary, which is an important layer to understand the changes in the processes influencing anisotropy.

We use a combination of array stacking techniques and synthetic seismogram modeling to separate and identify the phases. We initially focus on the region in the vicinity of the hemisphere boundary beneath the Pacific Ocean. By mapping the structure in this region, our results will allow us to better constrain the evolution of the hemispheres and anisotropy with depth and hence over time.