Satellite radar interferometry of Mt. Etna volcano, Sicily, Italy, reveals a sequence of deformation characterized by deflation during the end of the 1993 eruption, inflation from 1993--1995 with an increase in the inflation rate immediately before its resumed eruptive activity in late 1995. This was followed by very low deformation levels during the following year. The source of the deformation changed from a depth of 9 km during deflation to more than 11--14 km during the subsequent inflation, consistent with a model in which deflation at shallower levels is followed by inflation at greater depth as the volcano system recharges from below before its next eruption. This study demonstrates that radar interferometry provides an important contribution towards understanding the dynamic deformation of volcanoes. By revealing large scale changes in their pre-eruption deformation rates, radar interferometry could play an important role in volcano eruption monitoring. ¿ 1998 American Geophysical Union