Extreme Value Theory Modeling of Geochemical Anomalies: Block Maxima Approach

Abstract

Mineral shortages can be avoided if the mineral industry accurately predicts mineral deposits, which is critical given the importance of minerals in Ghana's economy. The goal of this dissertation was to use the block maxima (BM) approach of Extreme Value Theory (EVT) to accurately predict gold (Au) concentration and the time period of occurrence of these geochemical anomalies in Ghana's Wassa-Amenfi region. The information was based on a time series of daily gold concentrations collected between 2010 and 2018 by Ghana's geology and survey department. The shape parameter estimates from the analysis indicated that the Fréchet family of GEV distributions was a good fit for the dataset. The GEV model was used to forecast the occurrence of anomalies every 2, 5, 10, 20, 50, and 100 years. According to the findings, an extreme Au of 31.06 was expected to occur once every 5 years in Wassa-Amenfi.