2002 Volume 53 Issue 2-3 Pages 253-263
We have performed two-dimensional (2-D) interpretation of the Schlumberger sounding and mapping data that were obtained by the Directorate of Mineral Resources Inventory, Indonesia in the Bajawa geothermal field, central Flores Island, eastern Indonesia. There are three major surface geothermal manifestations, Mataloko, Nage and Bobo, in the study area. The aim of the Schlumberger survey was to investigate the deep resistivity structure for exploration of geothermal reservoirs in these areas. The 2-D resistivity models were obtained for ten, two and four survey lines in Mataloko, Nage and Bobo, respectively. Resistivity models of most lines have a surface high-resistivity layer that corresponds to less-altered young volcanic rocks, and a low-resistivity thick second layer that corresponds to alteration zones where conductive clay minerals might be abundant. A high-resistivity deep layer (resistivity basement) was recognized at a few zones including the Mataloko manifestation zone. The resistivity structure at the Mataloko manifestation, which is characterized by a very low-resistivity layer above the high resistivity basement, suggested an existence of a potential geothermal reservoir system. However, the investigation depth of the Schlumberger measurement, with a maximum electrode spacing AB/2 of 1,000 m or 2,000 m, was not sufficient to detect another deep high-resistivity layer that indicates an existence of geothermal reservoir.
