## 4 Results  
### Dimensionality Analysis: Polar Diagram  
This study utilized dimensionality analysis through polar diagrams and induction arrows. The polar diagram was plotted at different frequencies, indicating shallow to deep skin depths, respectively, 317 Hz, 100 Hz, 10 Hz, 1 Hz, 0.1 Hz, and 0.05 Hz, as shown in Figure 6. Observing Figure 6a and comparing it to the reference [39], we found that at the high frequency of 317 Hz, the absolute value of the polar diagram component, represented by \(|Z_{xx}(\alpha)|\), displayed a dominated flower petal shape, indicated in red. Meanwhile, the absolute value of the polar diagram component \(\left|Z_{xy}(\alpha)\right|\) exhibited a dominated circular shape, shown in black, reflecting the characteristics of the Earth model transitioning from 1D to 2D model. Some stations at the frequency of 317 Hz have an asymmetric flower petal shape for the \(|Z_{xx}(\alpha)|\) component and a peanut shape for the \(\left|Z_{xy}(\alpha)\right|\) component in C1, SARP, MANE, and D1 station, indicating a 3D model. At station D8, the characteristics of a  
Figure 5: (**a**) Planar view of the mesh for the inversion and (**b**) 3D view of the mesh for inversion, which were used in this research (the red box is the AOI which includes all the MT stations, and Rho is the model resistivity). The black triangles depict the MT station. 1D Earth model were depicted with no absolute value for the \(\left|Z_{xx}(\alpha)\right|\) component in the polar diagram, and a circular shape for the absolute value of the \(\left|Z_{xy}(\alpha)\right|\) component. In Figure 6b, at a frequency of 100 Hz, the absolute value of the symmetric flower petal shape dominates the absolute value component. The absolute value of the \(\left|Z_{xy}(\alpha)\right|\) component is dominated by a circular shape. This indicates a transition from a 1D to a 2D Earth model. However, certain stations (ACH2, MNYK, C1, D1, D4, and D7) exhibit a 3D asymmetric flower petal shape for the \(\left|Z_{xx}(\alpha)\right|\) component and a peanut shape for the \(\left|Z_{xy}(\alpha)\right|\) component. The C3, KEMA, and KAWA stations depict 1D geometric characteristics with no \(\left|Z_{xx}(\alpha)\right|\) component in the polar diagram, and a circular shape for the \(\left|Z_{xy}(\alpha)\right|\) component. In Figure 6c at a frequency of 10 Hz, the polar diagram component \(\left|Z_{xx}(\alpha)\right|\) shows an asymmetric flower petal shape, while the \(\left|Z_{xy}(\alpha)\right|\) component displays a peanut shape. This indicates a 3D Earth model geometry at stations ACH02, GEM, MNYK, MANE, C2, D1, D2, and D7. On the other hand, stations the KAWA, KEMA, and MBMG represent a 1D Earth model geometry as the \(\left|Z_{xx}(\alpha)\right|\) component (red) is absent, and the \(\left|Z_{xy}(\alpha)\right|\) component (black) is circular. The rest of the stations depict a 2D geometry shown by a symmetric flower petal shape for the \(\left|Z_{xx}(\alpha)\right|\) component and an elliptical shape for the \(\left|Z_{xy}(\alpha)\right|\) component. In Figure 6d, at a frequency of 1 Hz, the \(\left|Z_{xx}(\alpha)\right|\) component is predominantly an asymmetric flower petal shape. In contrast, the \(\left|Z_{xy}(\alpha)\right|\) component (black) is predominantly a peanut shape across all stations in Line D (D1, D2, D3, D4, D5, D7, and D8). This pattern is observed in most stations in Line A (ACH02, ACH04, ACH05, and ACH09), most stations in Line C (C2, C5, and C6), and the central part of Line B (SARP, MNYK, and MANE). No station shows 1D geometric characteristics. In Figure 6e, at a frequency of 0.1 Hz, most stations in Line A show the characteristics of a 3D Earth model geometry. This is shown by the \(\left|Z_{xx}(\alpha)\right|\) component (red) having an asymmetric flower petal shape, and the \(\left|Z_{xy}(\alpha)\right|\) component (black) having a peanut shape. The stations exhibiting these characteristics are ACH01, ACH02, ACH04, ACH05, ACH06, ACH07, PIDIB, MANE, KAWA, SARP, C3, and D4.