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

Ahmad Ali  Muckharom; Agus  Setyawan; Ihya Qothrunnada  Rahmani; Rina Dwi  Indriana; Agustya Adi  Martha

doi:10.6180/jase.202608_31.017

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

Physics

Ahmad Ali Muckharom¹, Agus Setyawan¹This email address is being protected from spambots. You need JavaScript enabled to view it., Ihya Qothrunnada Rahmani¹, Rina Dwi Indriana¹, and Agustya Adi Martha²

¹Department of Physics, Faculty of Science and Mathematics, Diponegoro University, Semarang Indonesia,50275

²National Research and Innovation Agency, Bogor Indonesia, 16911

Received: September 7, 2025
Accepted: November 30, 2025
Publication Date: February 8, 2026

Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.6180/jase.202608_31.017

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/m². 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.

Keywords: aeromagnetic, Curie point, heat flow, Sumatra Island, thermal gradient.

[1] N.A.Pambudi, (2018) “Geothermal power generation in Indonesia, a country within the ring of fire: Current status, future development and policy" Renewable and Sustainable Energy Reviews 81: 2893–2901. DOI: 10.1016/j.rser.2017.06.096.
[2] M. Abdurrachman, S. Widiyantoro, B. Priadi, and T. Ismail, (2018) “Geochemistry and structure of krakatoavolcano in the Sunda Strait, Indonesia" Geosciences 8: 111. DOI: 10.3390/geosciences8040111.
[3] A. E. Ringwood, (1990) “Slab-mantle interactions 3. Petrogenesis of intraplate magmas and structure of the upper mantle" Chemical Geology 82: 187–207. DOI: https: //doi.org/10.1016/0009-2541(90)90081-H.
[4] R. McCaffrey, (2009) “The tectonic framework of the sumatran subduction zone" Annual Review of Earth and Planetary Sciences 37: 345–366. DOI: https: //doi.org/10.1146/annurev.earth.031208.100212.
[5] C. Ramotoroko, E. Shemang, B. Lushetile, and M. Sitali, (2021) “Curie point depth analysis of aeromagnetic data of Kasane region in northwest Botswana and sur rounding regions for geothermal investigation of Kasane Hot Spring" Journal of African Earth Sciences 180: DOI: 10.1016/j.jafrearsci.2021.104214.
[6] D. Seshu, K. Kumar, S.S, P. Sivasankar, and P. Kumar, (2025) “Delineation of concealed banded iron formations (BIFs) below the Kurnool sediments in Palnadu Sub-basin, Macherla region, Cuddapah Basin through 3D inversion of aeromagnetic data" Geosystems and Geoenvironment 4: DOI: 10.10.1016/j.geogeo.2025.100357.
[7] T. O. Oyeniyi, T. I. Akanbi, and A. H. Falade, (2023) “An Application of Soft sign Function (SF) Filter to Low Latitude Aeromagnetic Data of Tafawa-Balewa Area, Northern Nigeria for Geostructural Mapping and Tec tonic Analysis" Results in Geophysical Sciences 14: 100063. DOI: 10.1016/j.ringps.2023.100063.
[8] M.N.Nabighian, (1972) “The Analytic Signal Of Two Dimensional Magnetic Bodies With Polygonal Cross Section: Its Properties And Use For Automated Anomaly Interpretation" Geophysics 37: 507–517. DOI: https: //doi.org/10.1190/1.1440276.
[9] R. D. Indriana, (2008) “Estimasi Ketebalan Sedimendan Kedalaman Diskontinuitas Mohorovicic Daerah Jawa Timurdengan Analisis Power Spectrum Data Anomlai Gravitasi" Berkala Fisika 11: 67–74.
[10] P. Kongpet and P. Kanjanapayont, (2024) “Curie point depth from airborne magnetic data analysis for geothermal exploration in southern Thailand" Journal of Asian Earth Sciences 261: DOI: 10.1016/j.jseaes.2023. 105984.
[11] O. Melouah, A. M. Eldosouky, and E. D. Ebong, (2021) “Crustal architecture, heat transfer modes and geothermal energy potentials of the Algerian Trias sic provinces" Geothermics 96: DOI: 10.1016/j.geothermics.2021.102211.
[12] M. Kassa, (2024) “Investigating subsurface structural lineaments of the northwest Ethiopian plateau using gravity data" Heliyon 10: DOI: 10.1016/j.heliyon.2024. e35520.
[13] J. A. Mono, T. Ndougsa-Mbarga, Y. Tarek, J. D. Ngoh, and O. U. I. Owono Amougou, (2018) “Estimation of Curie-point depths, geothermal gradients and near-surface heat flowfromspectral analysis of aeromagnetic data in the Loum– Minta area (Centre-East Cameroon)" Egyptian Journal of Petroleum 27: 1291–1299. DOI: 10.1016/j.ejpe.2018.07.002.
[14] R. Hall and C. K. Morley. Sundaland basins. Blackwell Publishing Ltd, 2004, 55–85. DOI: 10.1029/149GM04.
[15] Mapping subsurface structural lineaments using the edge f ilters of gravity data. 2015, 19–25.
[16] L. Thanh Pham, A. M. Eldosouky, O. Melouah, K. Abdelrahman, H. Alzahrani, S. P. Oliveira, and P. An dráš, (2021) “Mapping subsurface structural lineaments using the edge filters of gravity data" Journal of King Saud University- Science 33: DOI: 10.1016/j.jksus. 2021.101594.
[17] S. Maus, T. Sazonova, K. Hemant, J. D. Fairhead, and D. Ravat, (2007) “National geophysical data center candidate for the world digital magnetic anomaly map" Geochemistry, Geophysics, Geosystems 8: DOI: 10.1029/2007GC001643.
[18] S. Maus, U. Barckhausen, H. Berkenbosch, and N. Bournas, (2009) “EMAG2: A 2-arc min resolution Earth Magnetic Anomaly Grid compiled from satellite, air borne, and marine magnetic measurements" Geochemistry, Geophysics, Geosystems 10: DOI: 10.1029/ 2009GC002471.
[19] B. Meyer, A. Chulliat, and R. Saltus, (2017) “Derivation and Error Analysis of the Earth Magnetic Anomaly Grid at 2 arc min Resolution Version 3 (EMAG2v3)" Geochemistry, Geophysics, Geosystems 18: 4522 4537. DOI: 10.1002/2017GC007280.
[20] C. P. Ervin, (1976) “Reduction To The Magnetic Pole Using A Fast Fourier Series Algorithm" Computers Geosciences 2: 211–217. DOI: https: //doi.org/10.1016/0098-3004(76)90108-4.
[21] S. Kasidi, (2019) “Determination of Curie Point Depth, Heat Flow and Geothermal Gradient from High Resolution Aeromagnetic Data around Lamurde Area, Adamawa State, North-Eastern Nigeria" Open Journal of Geology 9: 829–838. DOI: 10.4236/ojg.2019.911093.
[22] N. Demarco, C. Prezzi, and S. Bettucci, (2021) “Re view of Curie point depth determination through different spectral methods applied to magnetic data" Geophysical Journal International 224: 17–39. DOI: 10.1093/gji/ggaa361/5881306.
[23] A. Tanaka, Y. Okubo, and O. Matsubayashi, (1999) “Curie point depth based on spectrum analysis of the magnetic anomaly data in East and Southeast Asia" Journal of Asian Earth Sciences 261: DOI: 10.1016/j.jseaes. 2023.105984.
[24] R. J. Blakely. Potential Theory in Gravity and Mag netic Applications. Cambridge University Press, Cam bridge Core, 1995.
[25] J. B. Thurston and R. S. Smith, (1997) “Automatic con version of magnetic data to depth, dip, and susceptibility contrast using the SPI (TM) method" Geophysics 62:
[26] I. H. F. C. (IHFC). Global Heat Flow Database. 2024.
[27] Y. Nasuti and A. Nasuti, (2018) “NTilt as an improved enhanced tilt derivative filter for edge detection of potential field anomalies" Geophysical Journal International 214: 36–45. DOI: 10.1093/gji/ggy117.
[28] O.Melouah,E.D.Ebong,K.Abdelrahman,andA.M. Eldosouky, (2023) “Lithospheric structural dynamics and geothermal modeling of the Western Arabian Shield" Scientific Reports 13: DOI: 10.1038/s41598-023 38321-4.
[29] S.A.Saada,(2016)“Curiepoint depth and heat flow from spectral analysis of aeromagnetic data over the northern part of Western Desert, Egypt" Journal of Applied Geophysics 134: 100–111. DOI: 10.1016/j.jappgeo. 2016.09.003.
[30] Determining the hydrothermal flow media using seismicity properties in Kaliulo geothermal field, Semarang, Central Java, Indonesia. 2021. DOI: 10.1088/1742-6596/ 1943/1/012031.