Seismic activity of Mt. Etna volcano has been investigated by analyzing time-spatial fractal dimensions and the b value of the Gutenberg-Richter's law relatively to two differing eruptive style periods, i.e. 1983--1988 and 1993--1996. The obtained results evidence two different volcano stress conditions before and after the large intrusive episode occurred during the time span 1989--1992. Fractal dimensions and the b value seem to be a promising tool to understand the internal current state of the volcano, allowing to evaluate the short-middle term volcanic hazard. ¿ 2001 American Geophysical Union