Regional variation of the omega values in the circum-Pacific belt

A data set of earthquakes which occurred in the circum-Pacific regions has been used to compute the omega values. This parameter is obtained through Gumbel's third asymptotic distribution of extreme values and is well known as upper bound magnitude. The results show relatively higher omega values in South America, Central America and Mexico, than in the western part of the circum-pacific belt. The results are interpreted in terms of the different mechanical structure (heterogeneity) of the materials in the eastern and western parts of the examined area.