Geothermal Resource Assessment on Sumatra Island: Estimating Thermal Gradient and Heat Flow Based on Aeromagnetic Data via Curie Point Analysis

Geothermal exploration on Sumatra Island is gaining momentum as Indonesia undergoes the shift to the use of sustainable energy resources. Exploration is nevertheless hindered by the limited deep boreholes and the tectonic and geological complexity of conditions on the island. This research examines the Curie point depth, which is derived from aeromagnetic data, utilizing Source Parameter Imaging (SPI) as an indirect means to calculate Heat Flow (HF) and thermal gradients of Sumatra Island. The Curie point ranges from 12.0 to 39.0 km , equivalent thermal gradient values range from 15.3 − 63.4°C/km and heat flow estimates of 38.2 − 205.7 mW/m^2. The results show a strong spatial coincidence between shallow Curie point areas and established geothermal provinces, particularly in Jambi, Lampung, and South Sumatra. Comparisons with global International Heat Flow Commission (IHFC) data also validate the results despite local heterogeneities caused by lithological, radiogenic heat generation, and hydrothermal heterogeneities. The study demonstrates that Curie point mapping offers a costeffective and scalable solution for geothermal exploration in data-poor regions. It also stresses the importance of greater integration with seismic, resistivity, and field-based geological studies to improve reservoir targeting in the more complicated tectonic settings.