Abstract
Results of 4 multivariate analyses for groundwater chemistry were compared to discuss which classification result is the most suitable to explain water chemistry in Shimabara city. Though characteristics of 5 clusters are almost same among all multivariate analysis methods, the distributions of each cluster were different among 4 methods. In the two methods using row data of 8 major ion concentrations, higher nitrate concentration points were not classified into polluted clusters. In this regards, the two methods using principal component scores obtained by principal component analysis seem better to represent classification of the field water chemistry because both of points are belong to nitrate pollution cluster. When the number of cluster was determined to 10, the method using principal component scores is more suitable than the other methods to explain water chemistry.
