This grant supports upgrade of the Penn State Seismological Computing Facility. The upgrade will entail purchase of an Apple Macintosh Xserve file server, four Macintosh dual 2.5 GHz G5 CPU workstations, each with 1 GB RAM, a linear tape drive backup system, and a 1.75 Tb RAID Apple Xserve mass store. The upgrade will foster a transition from an aging Sun file server/workstation network to an Apple MAC OS X based compute environment that will greatly simplify system administration tasks and increase by a factor of nearly four the compute power currently available to PI's Ammon, Richardson, Nyblade, and their students. Compute intensive research that will immediately be impacted by this upgrade include studies of the seismic structure of the crust and upper mantle beneath West Africa and the East-West Antarctic boundary, surface wave inversions, studies of mining induced seismicity, earthquake relocations, and nuclear explosion monitoring. ***
