Primary and Secondary Environmental Effects Triggered by the 30 October 2020, Mw = 7.0, Samos (Eastern Aegean Sea, Greece) Earthquake Based on Post-Event Field Surveys and InSAR Analysis

Abstract

On 30 October 2020, an Mw = 7.0 earthquake struck the eastern Aegean Sea. It triggered earthquake environmental effects (EEEs) on Samos Island detected by field surveys, relevant questionnaires, and Interferometric Synthetic Aperture Radar (InSAR) analysis. The primary EEEs detected in the field comprise coseismic uplift imprinted on rocky coasts and port facilities around Samos and coseismic surface ruptures in northern Samos. The secondary EEEs were mainly observed in northern Samos and include slope failures, liquefaction, hydrological anomalies, and ground cracks. With the contribution of the InSAR, subsidence was detected and slope movements were also identified in inaccessible areas. Moreover, the type of the surface deformation detected by InSAR is qualitatively identical to field observations. As regards the EEE distribution, effects were generated in all fault blocks. By applying the Environmental Seismic Intensity (ESI-07) scale, the maximum intensities were observed in northern Samos. Based on the results from the applied methods, it is suggested that the northern and northwestern parts of Samos constitute an almost 30-km-long coseismic deformation zone characterized by extensive primary and secondary EEEs. The surface projection of the causative offshore northern Samos fault points to this zone, indicating a depth–surface connection and revealing a significant role in the rupture propagation.

Emergency response, intervention, and societal recovery in Greece and Turkey after the 30th October 2020, MW = 7.0, Samos (Aegean Sea) earthquake

“…This earthquake induced primary and secondary effects on the natural environment of the island of Samos in Greece and the metropolitan area of Izmir in Turkey. In Samos, the primary effects included permanent surface deformation (uplift and subsidence) and co-seismic surface ruptures (Lekkas et al 2020a , b ; Mavroulis et al 2021 ). Primary effects of tectonic origin were not detected in Izmir (Cetin et al 2021 ).…”

“…Primary effects of tectonic origin were not detected in Izmir (Cetin et al 2021 ). The secondary earthquake environmental effects included a subsequent tsunami that caused damage mainly to coastal residential and commercial buildings of Samos and Izmir province (Triantafyllou et al 2021 ; Dogan et al 2021 ), slope movements, liquefaction phenomena, ground cracks, and hydrological anomalies in several sites of both affected areas (Lekkas et al 2020a , b ; Cetin et al 2021 ; Mavroulis et al 2021 ).…”

Site-Specific Earthquake Ground Motions for Seismic Design of Port Facilities in Indonesia

“…Port facilities are installed on soft soils in coastal areas; therefore, they are vulnerable to earthquakes. Earthquakes that occurred in other areas, such as the 1995 Kobe earthquake [6], the 1999 Kocaeli earthquake [7], and the 2020 Samos earthquake [8], also caused severe damage to port facilities and led to the stagnation of the social economy.…”