The Kaiser point (σK) was identified using an objective detection algorithm and qualitychecked with predefined validity criteria. A large part of the dataset was classified as nonvalid (validity depended on borehole and lithology, from ~56% up to 100%). The valid results indicate that carbonates can preserve a clear Kaiser effect and give reasonable stress-level estimates, while sandstones show weaker and more variable behaviour. In addition, the scatter and the share of problematic specimens decrease with increasing core depth, which supports the practical recommendation that future stress-memory drilling should reach at least ~10 m to reduce disturbance effects. In the next steps, the dataset will be extended by Felicity ratio analysis. This is recommended because it quantifies how early AE re-activates during reloading and provides an independent indicator of stress-memory degradation, improving the screening of disturbed specimens and strengthening confidence in the final stress interpretation. ACKNOWLEDGEMENTS This work was carried out within the EU Horizon Europe project - PERSEPHONE (Grant Agreement No. 101138451). REFERENCES Bai, X., Zhang, D.-M., Wang, H., Li, S.-J., & Rao, Z. (2018). A novel in situ stress measurement method based on acoustic emission Kaiser effect: A theoretical and experimental study. Royal Society Open Science, 5(12), 181263. https://doi.org/10.1098/rsos.181263 Blanksma, D. J. (2011). Investigation of in-situ stresses in rocks via acoustic emission and the Kaiser effect (Undergraduate senior project). University of North Dakota. Dinmohammadpour, M., Nikkhah, M., Goshtasbi, K., & Ahangari, K. (2022). Application of the Kaiser effect in in-situ stress measurement in rocks—An overview. Rudarskogeološko-naftni zbornik (The Mining-Geology-Petroleum Engineering Bulletin), 37(4), 1– 16. https://doi.org/10.17794/rgn.2022.4.1 Friedel, M. J., & Thill, R. E. (1990). Stress determination in rock using the Kaiser effect (Report of Investigations 9286). U.S. Bureau of Mines. Kharghani, M., Goshtasbi, K., Nikkhah, M., & Ahangari, K. (2021). Investigation of the Kaiser effect in anisotropic rocks with different angles by acoustic emission method. Applied Acoustics, 175, 107831. https://doi.org/10.1016/j.apacoust.2020.107831 Lavrov, A. (2003). The Kaiser effect in rocks: Principles and stress estimation techniques. International Journal of Rock Mechanics and Mining Sciences, 40(2), 151–171. https://doi.org/10.1016/S1365-1609(02)00138-7
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