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

[SEM12-P19] Geomagnetic Depth Sounding (GDS) Analysis Deep Structure of Taiwan: Insights from C-Response and Oceanic Induction Correction

*Ding-Jiun Lin¹、Ping-Yu Chang¹、Kiyoshi Baba²、Jordi Mahardika Puntu¹、Haiyina Hasbia Amania¹ (1.Department of Earth Sciences, National Central University, Taiwan、2.Earthquake Research Institute, University of Tokyo, Japan)

キーワード：Geomagnetic depth sounding, Mantle, 1-D conductivity model, Geomagnetic observatory

The main objective of this research is to utilize Geomagnetic Depth Sounding (GDS) for estimating C-response using data from even geomagnetic observatories in Taiwan and four international stations to study the deep structure. The analysis assumed a simple spherical harmonic, P01, to scrutinize spatial variations in the external geomagnetic field. To address the oceanic induction effect, a correction factor is introduced, comparing C-responses with and without a 3-D heterogeneous surface conductance layer. The resulting corrected C-responses are then converted into apparent resistivity for the inversion to derive a 1-D conductivity-depth profile. Based on response patterns and geological background, the conductivity variations in the Northern region, are attributed to the subducted Philippine Sea Plate. The model has higher conductivity levels (ranging from 0.05 to 1.50 S/m) within the depth interval of 300 km to 900 km, emphasizing the significant influence of subducted plates on the deep structure of Taiwan.