The project is part of a joint German-Indonesian research initiative to support technology and capacity building for geothermal energy development in Indonesia. Exploration methods such as active seismics and passive seismology, magnetotellurics and structural geology are combined in an integrated approach to investigate the Sipoholon geothermal field. The study area is located in northern Sumatra. The geological and tectonic framework is dominated by the Sumatran fault system and related pull-apart basins such as the Tarutung basin. Major fault structures and their interplay with subduction zone related young volcanism are responsible for enhanced heat flow and transport of fluids in the study area. Between may 2011 and february 2012 we run a temporary seismological network of 42 stations installed around the Tarutung basin. The data can be used to determine the detailed seismicity distributions together with tomographic images of Vp, Vp/Vs and intrinsic attentuation. These results will be used together with other geoscientific data to develop a conceptual model for the Sipoholon geothermal system.

Time Frame

• 05/2011 - 02/2012

Funding

• BMBF - Federal Ministry of Education and Research

Personnel

• Andri Hendriyana (GFZ Potsdam)
• Muksin Umar (GFZ, Syiah Kuala University, Banda Aceh)

Cooperations

• Badan Geologi
• Syiah Kuala University, Banda Aceh
• Universitas Sumatera Utara
• Institut Teknologi Bandung
• International Centre for Geothermal Research (ICGR) at GFZ Potsdam
• Trond Ryberg (GFZ Potsdam)
• Jacek Stankiewicz (GFZ Potsdam)

Methods & Equipment

• local earthquake tomography (Vp, Vs, Q)
• high resolution seismicity distribution
• fault plan solutions and stress field
• ambient noise tomography

Publications/Results

• Hendriyana, A., Bauer, K., Muksin, U., Weber, M. (2018): AIC-based diraction stacking for local earthquake locations at the Sumatran Fault (Indonesia). - Geophysical Journal International, 213, 2, 952-962. doi:10.1093/gji/ggy045
• Ryberg, T., Muksin, U., Bauer, K. (2016): Ambient seismic noise tomography reveals a hidden caldera and its relation to the Tarutung pull-apart basin at the Sumatran Fault Zone, Indonesia. Journal of Volcanology and Geothermal Research, 321, 73-84.
• Muksin, U., Haberland, C., Nukman, M., Bauer, K., Weber, M. (2014): Detailed fault structure of the Tarutung Pull-Apart Basin in Sumatra, Indonesia, derived from local earthquake data, Journal of Asian Earth Sciences, 96, 123-131.
• Muksin, U., Bauer, K., Haberland, C. (2013): Seismic Vp and Vp/Vs structure of the geothermal area around Tarutung (North Sumatra, Indonesia) derived from local earthquake tomography, Journal of Volcanology and Geothermal Research, 260, 27-42.
• Muksin, U., Haberland, C., Bauer, K., Weber, M. (2013): Three-dimensional upper crustal structure of the geothermal system in Tarutung (North Sumatra, Indonesia) revealed by seismic attenuation tomography, Geophysical Journal International, 195, 2037-2049.

Acknowledgement

The project is funded by the Ministry of Education and Research (BMBF). Seismological instruments and related software were provided by the Geophysical Instrument Pool Potsdam (GIPP). We wish to thank the project management, namely Kemal Erbas and Makky Jaya, for their valuable support of our seismology project. Particular thanks to all participants of the field work. The campaign was made possible by the active participation of the following colleagues:

• Benjamin Braeuer (GFZ Potsdam)
• Christof Lendl (GFZ Potsdam)
• Doddi Tampubolon (Universitas Sumatera Utara)
• Irwandi Nurdin (Syiah Kuala University, Banda Aceh)
• Jacek Stankiewicz (GFZ Potsdam)
• Klaus Bauer (GFZ Potsdam)
• Mekto P. Purba (Dinas Pertambangan, Tarutung)
• Muksin Umar (GFZ Potsdam, Syiah Kuala University, Banda Aceh)
• Nazli Ismail (Syiah Kuala University, Banda Aceh)
• Oki Hatauruk (Universitas Sumatera Utara)
• Tony Rahadinata (Pusat Sumber Daya Geologi, Bandung)
• Trond Ryberg (GFZ Potsdam)