For the project, Tromp will use seismic waves from roughly 3,000 quakes of magnitude 5.5 and greater, recorded at thousands of seismographic stations worldwide and distributed via the National Science Foundation's Incorporated Research Institutions for Seismology. These stations make recordings, or seismograms, that detail the movement produced by seismic waves, which typically travel at speeds of several miles per second and last several minutes.
"The ultimate goal is a 3-D map on a global scale," said Tromp, who expects to have preliminary results at the end of this year. "We are specifically interested in the structure of mantle upwellings and plumes," he said, "but much of it will be investigating the images for unusual features."
For the full article: http://www.princeton.edu/research/news/features/a/?id=14671