IDENTIFICATION OF AN UPPER PLEISTOCENE PA LAEOEARTHQUAKE IN THE RHONEVALLEY - IMPLICATIONS FOR THE UNDERSTANDING OF SEISMICITY IN FRANCE

Field work on palaeoearthquakes was carried out in the lower Rhone Val ley near the Nimes fault. In this area, where several superficial expr essions of Plio-Quaternary tectonic deformation had previously been re cognized, trenching led to the uncovering of a tectonic surface ruptur e that is very probably of seismic origin, and an analysis of the age of the most recent event is conducted. This discovery contributes to a better understanding of the relationships existing between surface ru pture, magnitude, and return period for major earthquakes in France.