ABSTRACT
Fulford, et al. (2002) stated that since the Newcastle earthquake in 1989, with a characteristic magnitude of a 1 in 1500 year return period earthquake, there has significant effects undertake into increasing engineering factorial calculations to a return period of 1 in 2500 years in Australia. According to AS/NZ
1170.4 (2007), this increment is the highest return period. Even though Paulay and Priestley (1990) have recommended the standardization of earthquakes to a 1 in 2500 return period for structural design calculation however it was considered impractical both from an engineering and economical point of view.
