9731383 Green This grant provides partial salary support for a technician at the UC-Riverside Tectonophysics laboratory. This is a Phase II grant for technical support under the EAR/IF program. The technician is essentially a machinist who provides the necessary high precision fabrication of parts for continued development of Dr. Green's modified multianvil device used in studies of the deformation mechanics of deep mantle phases. This innovative and unique high pressure multianvil device introduces shear stresses on samples contained in a NaCl confining media, thereby reducing piston frictional effects and resultant spatial temperature variations within the sample volume. Experimental results using this device with germanate and titanate analogues of deep mantle silicates has resulted in Green's hypothesis that deep-focus earthquakes within subduction zones are the result of a phase change from olivine to a spinel polymorph. Work in the arena of high-pressure phase change initiation of faulting continues with synthetic silicates and improvements in the engineering design of Green's modified multianvil device. These experiments hold considerable promise for our understanding of deep earthquake mechanics. ***
