Occurrence of Sarawet hotspring: what affects the outflow?

Abstract

Geothermal systems located in volcanic arc are generally influenced by volcanic activities. But at the complex geological setting like Sulawesi the geothermal systems probably is not only influenced by volcanic activities but also structural geology features. Sarawet hot spring in Minahasa, North Sulawesi, Indonesia is a volcanic and fault influenced manifestations. Sarawet hot spring is located in north coast Minahasa. Our study shows that the surface geological-structural analysis in combination with the geochemistry and the heat flow investigation is the essential tools for geothermal systems or manifestation characterization. Tectonics, crust characteristic, heat flow, and surface structural could affect the manifestations and its geothermal systems. Geochemically the water is bicarbonate, peripheral-immature water, and characterized by a meteoric water-line trend. The composition of these thermal springs was controlled by a secondary process during ascent. Based on hydrologic gradient, heat flow characteristic and subsurface structural analysis, the mechanism of Sarawet hot spring is a lateral outflow that affected by dynamically maintained fractures system.