A major earthquake (Mw=) occurred in the Samos Island on the 30th of October 2020 at 11:51 UTC. Swarm satellite magnetic data were analysed for 153 days before and 46 days after the earthquake. Preearthquake and postearthquake anomaly search is constrained within the Dobrovolsky’s Circular Area. Fundamentally, there are 5 steps for processing satellite magnetic data to interpret the earthquake preparation phase. The first step is converting geographical coordinates to geomagnetic latitude and longitude. Secondly, intensity of the external magnetic field should be evaluated by magnetic indices (Ap, Kp and |Dst). Thirdly, preearthquake and postearthquake magnetic anomaly should be constrained through magnetic indices (Ap | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 748-757 http earth TÜBİTAK Research Article doi yer-2107-9 Detection and interpretation of precursory magnetic signals preceding October 30 2020 Samos earthquake 1 2 İlkin ÖZSÖZ Oya ANKAYA PAMUKÇU 1 General Directorate of Mineral Research and Exploration Ankara 2 Dokuz Eylul University Engineering Faculty Geophysical Engineering İzmir Received Accepted Published Online Final Version Abstract A major earthquake Mw occurred in the Samos Island on the 30th of October 2020 at 11 51 UTC. Swarm satellite magnetic data were analysed for 153 days before and 46 days after the earthquake. Preearthquake and postearthquake anomaly search is constrained within the Dobrovolsky s Circular Area. Fundamentally there are 5 steps for processing satellite magnetic data to interpret the earthquake preparation phase. The first step is converting geographical coordinates to geomagnetic latitude and longitude. Secondly intensity of the external magnetic field should be evaluated by magnetic indices Ap Kp and Dst . Thirdly preearthquake and postearthquake magnetic anomaly should be constrained through magnetic indices Ap lt 20 Kp 3 and Dst ÖZSÖZ and ANKAYA PAMUKÇU Turkish J Earth Sci collapse. Additionally approximately 1030 injuries were 2. Data reported. After the earthquake ground fractures and The magnetic data used in this study have been obtained coastal uplifts were observed Μavroulis et al. 2021 . from the Swarm satellite constellation which is a European Southwest coast of İzmir and Samos Island was hit by a Space Agency ESA mission that contains three identical moderate tsunami Dogan et al. 2021 Triantafyllou et al satellites Friis-Christensen et al. 2006 . Three Swarm 2021 . The focal depth of the earthquake was estimated satellites which are Alpha Bravo and Charlie are identical at 21 km1. Samos earthquake has been investigated by and Alpha and .
