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

Spyridon Mavroulis,Ioanna Triantafyllou,Andreas Karavias,Katerina-Navsika Katsetsiadou,Gerassimos A Papadopoulos,Marilia Gogou,Issaak Parcharidis,Efthymios Lekkas

doi:10.3390/app11073281

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.

Highlights

IntroductionOn 30 October 2020 (11:51:26 UTC), a very strong earthquake measuring moment magnitude Mw = 7.0 ruptured offshore to the north of Samos Island in the eastern Aegean
On 30 October 2020 (11:51:26 UTC), a very strong earthquake measuring moment magnitude Mw = 7.0 ruptured offshore to the north of Samos Island in the eastern AegeanSea (Greece) (Figure 1) [1]
We focus on the environmental effects of the earthquake and present a detailed collection, documentation, and mapping of relevant field observations acquired during post-event field surveys conducted on Samos Island immediately after the earthquake event

Summary

Introduction

On 30 October 2020 (11:51:26 UTC), a very strong earthquake measuring moment magnitude Mw = 7.0 ruptured offshore to the north of Samos Island in the eastern Aegean. Fault plane solutions showed the activation of an E–W striking normal fault, which is likely dipping to the north [2,3] (Figure 1). Such a focal mechanism is consistent with the tectonic setting of the area [4,5,6,7,8,9,10]. The earthquake’s impact was more severe in the area of Izmir, western Turkey, to the north of the seismic source

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Conclusion