Collaborative Research: Africa Array--Imaging the African Superplume

Project: Research project

Project Details

Description

Collaborative Research:AfricaArray - Imaging the African Superplume

The African Superplume is a large region of low seismic wave speeds in

the lower mantle under southern Africa that has long been recognized as

one of the most prominent features of the mantle. Above the African

Superplume lies the African Superswell, suggesting a geodynamic link

between lower mantle dynamics and geologic processes shaping the

African plate. The origin and nature of the African Superplume is

controversial. The initial interpretation of the low wave speed region

under southern Africa attributed it to a long-lived, hot mantle

upwelling. A number of seismic studies since then have suggested the

presence of chemical heterogeneity within the superplume.

What parts of the superplume anomaly are thermal vs. chemical (or both)

remains uncertain, as does its origin. In this project, the structure,

composition and origin of the African Superplume will be investigated

using the first 3 years of broadband seismic data from AfricaArray,

together with existing data, and concentrating on four types of

analyses; 1) tomographic imaging of the upper and lower mantle using

body wave travel times, 2) modeling waveforms of teleseismic body wave

phases that sample the Superplume, 3) jointly inverting receiver

functions and surface wave dispersion measurements for crust and

uppermost mantle structure, and 4) stacking and migrating receiver

functions to image topography on the 410 and 660 km discontinuities.

AfricaArrayis a new 10-year-long Pan-African training and research

initiative in geophysics, with an emphasis on seismology, set up by the

University of the Witwatersrand, the Council for Geoscience (South

African geological survey), and Penn State. AfricaArraywill provide the

U.S. geophysics community with important seismic data on earth

structure and processes for many years. AfricaArraywill greatly

strengthen scientific ties between the U.S. geophysics community and

earth scientists throughout Africa. Once established, AfricaArraywill

provide opportunities for promoting geophysics to U.S. minority groups,

as well as other students, through summer internships and a summer

geophysics field course (both in Africa).

This award is co-funded by NSF's Office of International Science and Engineering.

StatusFinished
Effective start/end date3/1/052/28/09

Funding

  • National Science Foundation: $148,913.00

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