Deep Earth Structure National Meeting Summary Report

NEW NAME: Deep Earth Structure and Dynamics
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Preamble: This TWG is responsible for many orders of magnitude more of Earth’s mass, volume, heat, and pr essure than all the other TWGs put together. We should get 2 pages for our content!

Important objective: Mapping flow throughout the mantle from small to large scales, using self consistent seismology, dynamics, rheology, gravity, and mineral physics.

Target that relates to other TWGs: Unraveling the structure and evolution of the Yellowstone plume and its r elationship to subduction history. This directly relates to needing to significantly better constrain the structure, dynamics, and fate of slabs, as well as plumes, at much smaller scales. This work must be done.

Target that is more purely “deep Earth”: What is the nature of the inner and outer core? Is there fine scale outermost core layering? What is the nature of the CMB and finer scale D” phenomena? Are the recently imaged complexities (piles, anisotropy, ULVZ, post-perovskite, scatterers, etc.) ubiquitous? How much do these phenomena act as “tracers” to whole mantle dynamical flow?

Big risky expensive, yet super high return on investment idea: We advocate significantly increasing the number of seismic sensors in t he current USArray eployment. Two possibilities: super dense station spacing in a concentrated area, or, a coast to coast line with relatively close station spacing. If we wanted to ignore costs, a line of sensors traversing the Pacific from south-to-north, as well as from east-to-west would enable unparalleled 1st order discoveries.

Additional Tools: Realistic 3D synthetic seismograms at short period are necessary for testing and benchmarking models. Geodynamic predictions with realistic chemistry and rheology are also necessary.

Workshop Idea: "Mapping Deep Earth Flow"

Here we are inclined to define “deep” as sub-lithospheric, but acknowledge the subjective nature of doing so.