The seismicity of western Macedonia is examined in the present paper.
On the basis of historical information as well as on instrumental data
it is found that this area is characterized by low seismicity. The fo
cal region of the Grevena-Kozani 1995 earthquake exhibits the highest
seismicity in terms of probabilities for the generation of strong (M-s
, greater than or equal to 6.0) earthquakes in a period of fifty years
. Two other regions with relatively high seismicity were also distingu
ished (west of Edessa and around Prespes lakes). Accurate determinatio
n of focal parameters of all earthquakes occurred in the area during O
ctober 1975-April 1995, by the use of a 3-D crustal model shows that t
he seismic activity is related to the graben structures of the studied
area. Finally, evidence is presented that the triggering of the 1995
earthquake may be related to the impoundment of the Polyfytos artifici
al lake. (C) 1998 Elsevier Science Ltd. All rights reserved.