[S-EM12] Electric, magnetic and electromagnetic survey technologies and scientific achievements

[SEM12-P10] The analysis of aeromagnetic survey data across the Tendaho Graben in the Afar Depression, Ethiopia

*Ryosuke Ito¹, Ryokei Yoshimura², Mitsuru Utsugi¹, Shinichiro Higashino³, Tesfaye Kidane⁴, Ameha A Mulneh⁵, Balemwal A Alemu⁵, Shin-ichi Kagashima⁶, Nobutatsu Mochizuki⁷, Chie Kato⁸, Naoto Ishikawa⁹ (1.Graduate School of Science, Kyoto University, 2.Disaster Prevention Research Institute, Kyoto University, 3.Graduate School of Engineering, Kyushu University, 4.Wayne State University, 5.Addis Ababa University, 6.Faculty of Science, Yamagata University, 7.Faculty of Advanced Science and Technology, Kumamoto University, 8. Faculty of Social and Cultural Studies, Kyushu University, 9.Facultiy of Sustainable Design, Toyama University)

Keywords:Afar Depression, Aeromagnetic Survey

The Afar depression in Ethiopia is located at the triple junction of the divergent plate boundaries of the Nubian, Arabian and Somali plates. This area is considered to have progressed from continental rifting and is currently at the beginning stages of an ocean floor spreading, with the mid-oceanic ridges exposed onshore. In particular, in the area around Dabbahu volcano (Dabbahu Rift), there was active seismic activity and normal fault formation from 2005 to 2010, and lava eruptions were observed in some areas. Analysis of GPS and seismic data has estimated that there were repeated localized vein intrusions 10-60 km long and 1-3 m wide, with total vein intrusions ranging from 8 m wide, 60 km long and 2-10 km deep (e.g. Ebinger et al., 2010). Thus, the area must be an excellent field for exploring the subsurface structure of the ocean floor spreading axis area and the acquisition and formation process of magnetic anomalies.

Therefore, we carried out the aeromagnetic survey in the Afar depression in November 2019 and November 2023 using unmanned aerial vehicle. We detected long wavelength positive and negative magnetic anomalies at Tendaho Graven. In this study, the sparse magnetic inversion analysis (Utsugi, 2019) was applied to the data. In the presentation, we will discuss the distribution and structure of magnetic anomalies in the Dabbahu Rift and the processes that formed them.

This research was supported by JSPS Funds for the Promotion of Joint International Research (Fostering Joint International Research (B)) and Open Partnership Joint Research Projects of Bilateral program.