深海底マンガン団塊の広域概査における最適サンプリング密度

抄録

Standing on the economical point of view, the optimum sampling density for wide range prospecting of the ocean floor manganese nodules was derived using a geostatistical method. A variogram was calculated from the existing sampling data of the ocean floor manganese nodules. Consequently the weak-stationarity of the area was certified, and the abundance distribution of the manganese nodules was calculated by means of Kriging. It was found that the frequency distribution of the abundance of the manganese nodules presented a lognormal distribution. The data used had been acquired from the ocean floor south of Hawaii.
The relation between Kriging deviation and the economical loss induced by estimation error was calculated. Also the relation between the sampling density and the expected value of Kriging deviation was calculated. From the both relations, we obtained the relation between the sampling density and the loss induced by estimation error. Considering the relation between the sampling density and the total sampling cost, the optimum sampling density from economical aspect was calculated for each cutoff values.