Dr Jenny Jenkins will present her recent work on ultra-low velocity zones.

Title: "High-resolution seismic imaging of the Hawaiian ultra-low velocity zone"

Abstract:
Within the complex landscape of the Earth's core-mantle boundary, no feature is more extreme, or more poorly understood, than ultra-low velocity zones (ULVZs). While most material within the Earth causes changes in seismic wave speed by only several percent, ULVZs show wave speed reductions of 10-50%. While several hypotheses have been proposed to explain these extreme observations, what exactly ULVZs are made of, and what effect these small piles of material have on surrounding mantle processes is still an open question.  In this talk, I'll present a new large-scale regional map of the Hawaiian ULVZ based on observations of core bouncing seismic waves (ScS phases), and discuss what constraints these new observations provide on ULVZ material and its interactions with lower mantle convection.