## 4 Results
### Results of Coulomb Failure Stress Changes  
The resolved principal stress axes' directions were used for the \(\Delta CFS\) calculations by the method described in Section 3.1. Table 2 presents information regarding the eight earthquakes that were incorporated into the calculations. As shown in Figure 3, we calculated the \(\Delta CFS\) induced by eight earthquakes larger than 6 \(M\)W in the study area from 1986 to 2023 (specific calculated values see Tables S3 and S4 in Supplementary Materials). The upper section of the figure presents the \(\Delta CFS\) resulting from earthquakes occurring at a depth of 10 km below the surface, while the lower section depicts the \(\Delta CFS\) along the vertical plane of the AB line indicated in the upper section. Figure 3a illustrates the \(\Delta CFS\) associated with four earthquakes of magnitudes greater than 6 \(M\)w that occurred in eastern Turk'iye between 1986 and 2020. Notably, since none of these earthquakes overcame a magnitude of 7 \(M\)w, the resultant \(\Delta CFS\) was relatively modest. The vertical plane representation reveals that the \(\Delta CFS\) from the earthquakes of 1986 and 1998 only influenced the subsurface to a depth of 20 km. The 1986 earthquake, with a magnitude of 6.0 \(M\)w, generated a \(\Delta CFS\) averaging 0.41 bar at a depth of 10 km. In the AB vertical \begin{table}
\begin{tabular}{c c c c c c} \hline
**Azimuth1** & **Plung1** & **Azimuth2** & **Plung2** & **Azimuth3** & **Plung3** \\ \hline
197.3915 & 20.51909 & 352.331 & 67.5516 & 104.1035 & 8.712759 \\ \hline
**See** & **Sen** & **Seu** & **Snn** & **Snu** & **Suu** \\ \hline \(-0.646715\) & \(-0.442439\) & 0.181673 & 0.851544 & 0.236023 & \(-0.204829\) \\ \hline
**Strike1 (°)** & **Dip1 (°)** & **Rake1 (°)** & **Strike2 (°)** & **Dip2 (°)** & **Rake2 (°)** \\ \hline
347.600 & 88.049 & \(-157.630\) & 221.980 & 72.523 & \(-14.314\) \\ \hline \end{tabular}
\end{table} 
Table 1: The results were calculated by STRESSINVERSE. Figure 2: Inversion results calculated by STRESSINVERSE. (**a**) Confidence of principal stress axes: the 95% confidence region in the direction of the principal stress axes for the best-fit stress tensor model (red for \(\sigma_{1}\), green for \(\sigma_{2}\), blue for \(\sigma_{3}\)); (**b**) Mohr circle diagram: fault planes selected for all events in the Mohr circle; (**c**) principal stress and P/T axes P/T axes for all events and the principal stress directions of the best-fit stress tensor. The red circles represent the pressure axes (P-axes), and the blue plus signs represent the tension axes (T-axes). The green dot represents \(\sigma_{1}\), the cross represents \(\sigma_{2}\), and the plus sign represents \(\sigma_{3}\); (**d**) shape ratio: frequency histograms of the R-value. plane, positive \(\Delta CFS\) values were predominantly located closer to the surface, averaging at 0.96 bar, while the averaging negative value was \(-\)0.93 bar. The 6.2 \(M\)w earthquake in 1998 did not produce extensive areas of significant positive or negative \(\Delta CFS\) at the 10 km depth, with mean positive and negative values of 0.33 bar and \(-\)0.77 bar, respectively. However, the AB vertical plane exhibited a substantial area of elevated positive \(\Delta CFS\) values above the 10 km depth, reaching a mean value of about 2.2 bar, indicating a heightened likelihood of subsequent seismic activity near the epicenter at depths up to 10 km. Conversely, negative \(\Delta CFS\) values were primarily located below the 10 km depth, with an averaging value of \(-\)0.41 bar. The 2003 earthquake, with a magnitude of 6.3 \(M\)w, demonstrated a slightly broader range of effects, yet did not extend beyond 30 km into the subsurface. It produced an average \(\Delta CFS\) value of 0.75 bar on the plane at 10 km. The Coulomb stress changes induced by this earthquake show two regions of high values with a mean of about 2.8 bar near the surface not more than 10 km below ground. The 2020 earthquake with 6.8 \(M\)w, exhibited a more extensive influence, extending to a depth of 50 km.