[2] She found that there is heterogeneity in the composition of the lowermost mantle, with denser than average material beneath the Pacific Ocean and Africa.
[10] Through her research program, Ishii has continued to refine and enhance the back projection methods she developed as a postdoctoral fellow.
She integrates data taken by networks of seismic instruments from around the world, allowing her to more accurately map out the trajectory of earthquake waves.
[10] Ishii has also made use of global positioning system (GPS) network data in order to search for deformities within Earth's internal structure.
[10] The rocks and minerals that lie in the mantle—the layer of the Earth between the crust and the inner core—move in slow convection cycles due to the enormous heat and pressure that exist within the mantle.
Through preliminary computer simulations, Ishii and colleagues found that a long segment (about 390 km) of the Japan Trench had ruptured during the earthquake over the course of two to three minutes.
[14] Much like the X-rays and CAT-scans used in medical imagining, seismic waves bounce around and change direction based on the medium they pass through, which can give researchers an idea of the composition of Earth's interior.