Source modelling and stress transfer scenarios of the October 30, 2020 Samos earthquake: seismotectonic implications

Abstract

On October 30, 2020, a strong earthquake (M w 6.6-7.0) occurred offshore, just north of Samos Island, causing life losses, injuries and damages, especially on the Turkish side. The broader area is characterized by a complex geodynamic setting with both rich seismic history and numerous active faults of different direction and kinematics. The first aim of this study is to define the seismic source of the mainshock, based on seismological and geodetic data (GPS measurements and originally processed GNSS records), as well as our field observations on Samos Island few days after the mainshock. The integration of this information leads to a N-dipping normal fault (Kaystrios fault) that controls the central-northern coast of Samos Island. We modelled the seismic source and calculated the theoretical dislocation (using the Okada formulae) on the surrounding GPS/GNSS stations, comparing it with the measured values. The results are very encouraging, especially on the station installed on Samos Island, giving confidence to our source model. We then used our seismic source to study the spatiotemporal evolution of the aftershock sequence by exploiting published seismological data (focal mechanisms and two seismic catalogues, one of which with relocated hypocentres) and our calculated Coulomb static stress changes caused by the mainshock. This comparison suggests that more faults than the Kaystrios fault were involved in the aftershock sequence. In order to investigate possible triggering and/or delay scenarios of the mainshock on nearby faults, the Coulomb stress changes are also studied showing various results according to each receiver fault.

The Predictability of the 30 October 2020 İzmir-Samos Tsunami Hydrodynamics and Enhancement of Its Early Warning Time by LSTM Deep Learning Network

“…On 30 October 2020 at 12:51 p.m. UTC, an earthquake with a moment magnitude of 6.9 Mw with its epicenter off the Greek island of Samos, approximately 23 km south of ˙Izmir occurred [25][26][27]. The analysis carried after the kinematic rupture process of the earthquake indicated the cascaded rupture of two fault planes, with slightly rotated strike angles, and dominated by normal faulting and oblique faulting, respectively [27].…”

Assessing the Scale Effect on Bearing Capacity of Undrained Subsoil: Implications for Seismic Resilience of Shallow Foundations

“…Love waves are horizontally polarized shear waves that cause the ground to move side to side. Rayleigh waves are elliptically polarized waves that cause the ground to move up and down and side to side in a rolling motion [ 57 , 58 , 59 ].…”

The Upper Crustal Deformation Field of Greece Inferred From GPS Data and Its Correlation With Earthquake Occurrence

“…This indicates that the active structures in the eastern and northeastern Aegean accommodate significant strain and are associated with elevated earthquake hazard. This increased strain accumulation was notoriously expressed the previous years by the occurrence of the 2017 M w 6.3 Lesvos and M w 6.6 Kos earthquakes (e.g., Kiratzi, 2018; Konca et al., 2019; Sboras et al., 2020) and the 2020 M w 7.0 Samos earthquake (e.g., Chousianitis & Konca, 2021; Hu et al., 2022; Sboras et al., 2021).…”