Contouring the intensity data for the largest earthquakes recorded in Southern Italy yields areas delineated by the M.C.S. X, IX, VIII isoseisms that are markedly elongated along the axial direction of the Apennine Chain.
To evaluate the attenuation of intensity with distance, four regression curves have been calculated using empirical relations of the form:
I (R) -Io = a + bR + clogR
in accordance with Chandra's procedure [9]. The results are compared with the attenuation relation used for the « shake ability » map of Italy. New mag¬nitudes for historical earthquakes have been calculated and an earthquake fault map is proposed. In addition, a comparison has been made between recent and historical earthquakes in some areas, including those of different magnitude, in an attempt to quantify the energies associated with the histo¬rical events
