Research: Structure of the Inner Core from Exotic Core Phases

The core is a particularly active section of our planet, yet there are relatively few constraints on many of its properties. It can be explored through studying the body waves which pass through it, including the shear wave PKJKP and the reflected compressional phase PKIIKP; the observation of these exotic core phases is highly dependent on the impedance contrast at the inner core boundary and the attenuation throughout the core.

The inner core is composed mostly of iron, gradually growing through solidification as the Earth cools. This mechanism drives convection in the outer core and mantle and thus helps to power plate tectonics and the geodynamo. However, comparatively little is known about the dynamics at the inferface and its transition zone. Furthermore, the attenuation within the inner core remains poorly constrained. The inner core shear attenuation quality factor Qμ is taken by PREM to be 84.6, however other studies have found it to have values in excess of 400.

I have made several observations of both inner core shear phases and reflected compressional phases in a number of different events. My current research uses these observations to place improved constraints on the inner core shear attenuation, providing implications for the material structure.

 


Last updated on 22-Jun-10 09:54