Geological Society of Greece 179 Volume 58 Research Paper THE SCALING OF PGA WITH IV2P AND ITS POTENTIAL FOR EARTHQUAKE EARLY WARNING IN THESSALY (CENTRAL GREECE) Ioannis Spingos 1,2 , Filippos Vallianatos 1,2 * , and George Kaviris 1,2 1 Section of Geophysics–Geothermics, Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, 15784 Athens, GR 2* Institute of Physics of the Earth’s Interior and Geohazards, UNESCO Chair on Solid Earth Physics and Geohazards Risk Reduction, Hellenic Mediterranean University Research Center, Crete, GR 73133 Chania, Greece; fvallian@hmu.gr, fvallian@geol.uoa.gr, +302107274360 Abstract The main goal of an Earthquake Early Warning System (EEWS) is to estimate the expected peak ground motion of the destructive S-waves using the first few seconds of P-waves, thus becoming an operational tool for real-time seismic risk management in a short timescale. EEWSs are based on the use of scaling relations between parameters measured on the initial portion of the seismic signal, after the arrival of the first wave. Herein, using the abundant seismicity that followed the 3 March 2021 Mw=6.3 earthquake in Thessaly we propose scaling relations for PGA, from data recorded by local permanent stations, as a function of the integral of the squared velocity (IV2p). The IV2p parameter was estimated directly from the first few seconds-long signal window (tw) after the P-wave arrival. Scaling laws are extrapolated for both individual and across sites (i.e., between a near-source reference instrument and a station located close to a target). The latter approach is newly investigated, as local site effects could have a significant impact on recorded data. Considering that further study on the behavior of IV2p is necessary, there are indications that this parameter could be used in future on-site single‐station earthquake early warning operations for areas affected by earthquakes located in Thessaly, as it presents significant stability. Keywords: earthquake; early warning system; on-site; Thessaly; IV2p Correspondence to: Filippos Valianatos fvallian@geol.uoa.gr DOI number: http://dx.doi.org/10.12681/ bgsg.27062 Keywords: Earthquake, early warning system, on-site, Thessaly, IV2p Citation: Spingos, I., Vallianatos, F. and Kaviris, G. (2021), The Scaling of PGA with IV2p and Its Potential for Earthquake Early Warning In Thessaly (Central Greece). Bulletin Geological Society of Greece, 58, 179-199. Publication History: Received: 19/05/2021 Accepted: 06/09/2021 Accepted article online: 13/09/2021 The Editor wishes to thank one anonymous reviewer and Dr. Ch. Evangelidis for their work with the scientific reviewing of the manuscript and Ms Emmanouela Konstantakopoulou for editorial assistance. ©2021. The Authors This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited BGSG