“…This is mainly because the prediction performance of multivariate prediction techniques is based heavily on the strength of the linear correlation between the samples of primary and secondary variables at co-located locations (Erten, 2012). The complementary geophysical information can be incorporated into the kriging procedure using multivariate geostatistical modelling techniques, such as simple kriging with varying local means (SKLM), ordinary co-located cokriging (OCCK), ordinary cokriging (OCK), kriging with external drift (KED), and Bayesian integration (BAY) (Bardossy et al , 1986; Bourennane and King, 2003; Dowd and Pardo-Iguzquiza, 2006; Doyen, 1988; Erten et al , 2013; Kay and Dimitrakopoulos, 2000; Xu et al , 1992).…”