Irvine and Varagarに従った火山岩の分類結果の検討 (1)
―アルカリ・サブアルカリの分類について―
1987 年 1987 巻 12 号 p. 127-141
詳細
1987 年 1987 巻 12 号 p. 127-141
The results for the major chemical groups (alkaline, subalkaline) classified according to Irvine and Varagar's volcanic rock classification scheme were tested by discriminant analysis. For this purpose, 146 major chemical analysis data of volcanic rock samples were used. In these data, 68 samples were classified as subalkaline group, 78 samples were classified as subalkaline group by Irvine and Varagar's volcanic rock classification scheme.
There are two methods by means of linear discriminant function and quadratic discriminant function in discriminant analysis. The discriminant analyses using two functions were adopted for the two major chemical groups classified as alkaline and subalkaline.
The number of error discriminations is 4 for subalkaline group, and is 0 for alkaline group in linear discriminant function analysis. The correct discriminations are 89.7% and 100% for subalkaline and alkaline groups, respectively. The mean error discrimination is 4.7%. In discriminant analysis using quadratic function, the number of error discriminations are 4 and 2 for subalkaline and alkaline groups, respectively. The correct discriminations for subalkaline and alkalinegroups are 94.1% and 97.4%, respectively.The mean error discrimination is 4.0%. The number of error discriminations are very few in discriminant analyses using both linear and quaratic functions. The probability of correct classification for two groups is more than about 90%. It is estimated that Irvine and varagar's volcanic rock classification scheme can be classified major chemical group reliably.
