## 5 Conclusions  
This study presents a quantitative analysis of crustal deformation in southeastern Korea by integrating dense GNSS baseline measurements with elastic tensor modeling. Temporal and spatial comparisons of strain and stress fields revealed notable shear strain accumulation along the central segment of the Yangsan Fault, consistent with ongoing tectonic loading. The results demonstrate the effectiveness of GNSS-derived strain tensors in distinguishing between steady-state and transient deformation regimes in intraplate environments.  
The findings highlight the importance of deploying a spatially optimized and structurally stable GNSS network, particularly in regions near active faults. Enhanced spatial resolution, combined with continuous high-frequency monitoring, would improve the ability to resolve localized deformation and assess seismic hazard with greater confidence. In light of the proximity of critical infrastructure and active fault systems, a strategic upgrade of Korea's geodetic infrastructure should be considered.  
By applying a physically grounded elastic strain framework, this study provides a methodological foundation for linking surface deformation patterns to underlying fault behavior. Future work should incorporate fault mechanics, real-time stress monitoring, and integrated modeling to further refine assessments of fault stability and seismic risk in structurally complex intraplate settings.  
Figure 12: Conceptual framework for integrating GNSS-based strain analysis into seismic hazard assessment and policy planning. The process begins with data acquisition and preprocessing, utilizing GNSS network observations alongside supplementary geological and seismological datasets. This is followed by strain analysis, where digital strain tensor solutions are derived to extract principal and maximum shear strains and infer regional stress orientations. In the hazard assessment phase, anomalies in strain patterns are identified and mapped to delineate zones of elevated seismic risk. Finally, outputs feed into policy and planning applications, enabling the formulation of risk mitigation strategies and the development of probabilistic seismic hazard models and forecasts (PSHM). This framework highlights a multidisciplinary approach that enhances the reliability and applicability of strain-based assessments in tectonically active yet low-seismicity intraplate regions.  
**Author Contributions:** Conceptualization, S.-J.L., S.-H.L. and H.-S.Y.; methodology, S.-J.L., S.-H.L. and D.-H.S.; software, S.-J.L. and S.-H.L.; validation, S.-J.L., S.-H.L. and [PERSON]-[PERSON]; formal analysis, S.-J.L., [PERSON]-H.L. and [PERSON]-H.S.; investigation, [PERSON]-J.L. and [PERSON]-H.L.; resources, S.-J.L., [PERSON]-H.L. and [PERSON]-H.S.; data curation, S.-J.L., [PERSON]-H.L. and [PERSON]-H.S.; writing--original draft preparation, S.-J.L. and S.-H.L.; writing--review and editing, H.-S.Y. and D.-H.S.; visualization, S.-J.L., [PERSON]-H.L. and [PERSON]-H.S.; supervision, H.-S.Y.; project administration, H.-S.Y.; funding acquisition, H.-S.Y. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS-2021-NR059478).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** The authors declare no conflicts of interest.