The implementation of 10 short-period seismic stations in French Polynesia since 1963 allowed the detection of previously unnoticed seismic activity in the central South Pacific (5¿--30¿S, 125¿--160¿W). The epicenter location, the depth, and the magnitude of all major events which occurred in this region are tabulated. The Tahiti-Mehetia region, which is the zone of activity closest to the stations, is studied in detail. Swarms of earthquakes are observed at two well-defined sites. Their similarity to typical preeruptive swarms, their location near two seamounts, and the general volcanic context are considered indicative of two active submarine volcanoes. The existence of a 'hot spot' at the southeastern tip of the Society Island chain is suggested.