We are now extending our work to the finer 3 by 3 grid in the mantle while retaining our current 6 grid in the Earth's core. Thus, we will be able to estimate velocity structure and assess its reliability on a finer scale. The new finer grid will have almost 4 times the number of parameters. In order to estimate resolution and uncertainty, we must calculate between 10,000 and 30,000 Lanczos values and vectors. An image of the compressional velocity variation within the Earth's mantle, that is, the velocity at which seismic waves propagate through the mantle.
Cold colors signify higher average velocities, while warm colors signify lower velocities.
The high velocities circling the Pacific are thought to represent subducting crust associated with plate tectonics. Significance To date, seismic research has focused on specific regions of the Earth, such as the mantle, using only data most sensitive to these regions. Ours is the first study to attempt to utilize all seismic arrival times to solve for the structure of the entire Earth-crust, mantle, and core. We are also the first to conduct a thorough assessment of our model by calculating model parameter resolution and uncertainty. No one to date has adequately characterized the reliability of the finer-scale models, so, it is not clear if the seismic data actually allow us to image such fine details.