THE JUNE 9 BOLIVIA AND MARCH 9 FIJI DEEP EARTHQUAKES OF 1994 .2. GEODYNAMIC IMPLICATIONS

The June 9, 1994 Bolivia earthquake (Mw=8.2) occurred in the pronounce d bend in the morphology of the deep South American slab, where severa l dynamic arguments can be put forward to explain the apparently anoma lous mechanism and the horizontal fault plane; the size of the event i s huge but expected when the regional seismicity of the whole century is considered. The March 9, 1994 Fiji earthquake (Fiji=7.5) suggests t hat a new mode of seismic deformation is active in the northernmost te rmination of the Tonga-Fiji slab, cutting across the dense cluster of seismicity of the last 30 years; the size of the event is probably clo se to the largest to be expected over a century in this area, having t he steepest frequency-moment distribution of all global. deep seismici ty.