The damage during earthquakes is caused by many factors depending on source
, site and structural characteristics. The earthquake source mechanism and
response of local site conditions are complex and may vary significantly fr
om one earthquake to the other and from one site to the other. These diffic
ulties and ambiguities in forecasting the seismic hazard in terms of expect
ed earthquake characteristics affecting the man-made environment are discus
sed and possible alternative approaches are suggested. (C) 2001 Published b
y Elsevier Science Ltd.