[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

*伊藤 良介¹、吉村 令慧²、宇津木 充¹、東野 伸一郎³、Kidane Tesfaye⁴、Mulneh Ameha⁵、Alemu Balemwal⁵、加々島 慎一⁶、望月 伸竜⁷、加藤 千恵⁸、石川 尚人⁹ (1.京都大学理学研究科、2.京都大学防災研究所、3.九州大学工学研究院、4.Wayne State University、5.Addis Ababa University、6.山形大学理学部、7.熊本大学大学院先端科学研究部（理）、8.九州大学比較社会文化研究院、9.富山大学都市デザイン学部)

キーワード：アファール凹地、空中磁気測量

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.