The study will investigate the mechanisms and kinetics of phase transitions in mantle materials at high pressures and temperatures using using a special high pressure apparatus designed to apply a controlled shear stress to the sample while at high pressure and temperature. The sample will be examined by optical microscope, in situ x-ray diffraction at high pressures and temperatures using synchrotron radiation, and post mortem electron microscope and microprobe analyses. Experimental information on the dynamic behavior of mantle materials at pressures and temperatures that exist within the transition zone of the mantle will be very valuable for understanding the origin and nature of deep focus earthquakes.
