Seismicity and tectonic stress in the south-central Pacific.

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-Mehetia 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 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. -Authors