9706219 Wallace This research is to study the rupture characteristics of deep earthquakes. The cause of deep earthquakes remains one of the most important scientific questions in earth sciences. Most of the work to date has concentrated on the rise time of the seismogram and the implied rupture initiation phase. Work on the later growth of the fault surface area and termination of the rupture process has waited on the development and installation of very wide-band seismometers of the Global Seismic Network. In the two largest recent deep earthquakes, the 1994 M=8.3 Bolivian and 1996 M=7.9 Flores Sea events, the rupture velocity appears to be very slow, less than 2.6 km/s as compared to shallow earthquakes. It is possible that this slow rupture is a product of an exotic slip-weakening mechanism, for example, pressure-release melting. However, not all deep earthquakes appear to have extraordinarily slow rupture, complicating any single explanation. This research involves the investigation of the rupture of more than 20 events ranging in depth from 80 to 640 km. ***
