Values in parantheses were derived for a rectangular fault model. Conclusions T he Fiji-Tonga event like the Flores Sea event was characterized by high rupture velocity and moderate stress drop. The great Bolivian deep earthquake of June 1994, on the other hand, was associated with a low rupture speed and high static stress drop. Thus the focal process may have occured within a wedge of metastable olivine in conformity with the transformational-faulting model. However, it is not possible to put forward a similar argument for the 1994 Fiji-Tonga event.
Rupture extends perpendicular to the strike of the deep seismic zone.
McGuire et al. The nucleation phase of the event occurred in the cold core of the slab and was perhaps triggered by transformational faulting in metastable olivine. Rupture in the warmer surrounding areas may be caused by other mechanisms such as ductile faulting, plastic instabilities or frictional heating.