The 15-station French Polynesian Seismic Network is used to study the intraplate seismicity of the South-Central Pacific Ocean for the period January 1, 1965 to December 31, 1979. The overall pattern of seismicity shows a clustering of earthquakes at approximately 30 distinct localities, occurring both as discrete events and in swarms. Three localities are associated with known centers of active vulcanism (Moua Pihaa and Rocard seamounts in the Tahiti-M¿h¿tia area and Macdonald seamount in the Austral Islands). A set of eight localities is distributed along the tectonic axis of the Tuamotu Archipelago and its northwestward extention into the Line Islands, and a set of five is roughly aligned with the northeastern edge of the Tuamotu platform; both sets may be related to load inhomogeneities in the lithosphere. However, much of the seismicity is not correlated with major bathymetric features. With the exception of one isolated event, for example, none of the recorded activity occurs along the major fracture zones that cross the study area. Only three localities have been the sites of two or more earthquakes with body-wave magnitudes greater than 5.0; these we designate Regions A, B and C. Excluding Hawaii, Regions A, B and C are the most intense centers of seismicity within the Pacific plate interior, and together they account for more than 90% of the seismic energy release in the South-Central Pacific. An analysis of water multiples from events in Regions A, B and C indicates hypocentral depths within the oceanic crust. Eight focal mechanisms have been obtained; these all have nearly horizontal, NW-trending compressional axes, oriented approximately parallel to the direction of Pacific plate motion. The uniformity of this orientation over the large distances separating the epicenters (>2000 km) suggests that the mechanisms are indicative of a regional tectonic stress field, rather than locally disturbed stress patterns. These data thus provide additional constraints on the force balance models of plate tectonics.