Hg Air Survey at Makaroyen Village in Kotamobagu Geothermal Field, North Sulawesi, Indonesia

Abstract

Kotamobagu geothermal field is one of the prospects of geothermal development in North Sulawesi, Indonesia. We conducted soil air gas (Hg air) survey in Kotamobagu, mainly within Makaroyen village, on the foot of Ambang Mountain. Concentrations of Hg air, were measured for 20 sampling points in the area of 1.0 km EW and 1.0 km NW with elevation around 1000 m above sea level. High concentrations of Hg air, 2.40 to 2.72 ng/day, were mainly measured in the center and northeast of the study area whereas lower concentrations to the south and to the west. High concentration of Hg air above 2.40 ng/day was detected in the center and northeast of the area Makaroyen village. The presence of flow path of high temperature fluid and heat source is expected below the areas with high concentrations of Hg air.