The aftershock activity of the Samos earthquake (M-w =7.0) of October 30, 2020: aftershock regime and a new method for estimating aftershock duration

UTKU M.

ARABIAN JOURNAL OF GEOSCIENCES, vol.15, no.1, 2022 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 15 Issue: 1
  • Publication Date: 2022
  • Doi Number: 10.1007/s12517-021-09224-3
  • Journal Name: ARABIAN JOURNAL OF GEOSCIENCES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Agricultural & Environmental Science Database, Aquatic Science & Fisheries Abstracts (ASFA), Geobase, INSPEC
  • Keywords: Aftershock, Aftershock duration, Earthquake source, Fault plane, Rupture propagation, Rupture velocity, Completeness plane, WESTERN TURKEY, TECTONICS, DISCRIMINATION, MAGNITUDE, ANATOLIA, AREA, LAW
  • Dokuz Eylül University Affiliated: Yes

Abstract

The Samos (Sisam) Island earthquake of October 30, 2020 (11:51:25 UTC, M-w = 7.0, M-L = 6.6, depth = 12 km) was a major earthquake with an epicenter in the Aegean Sea, similar to 10 km north of Samos Island and >= 40 km from the Aegean region of Turkey. The main stages of this study were the analysis of the aftershock regime of the earthquake, the correlation of this regime with the kinematics and the determination of seismic wave propagation and aftershock duration. In the subsequent 2 months, there were 4783 aftershock earthquakes (1.0 <= M-L <= 5.3) within the earthquake's deformation zone. The cause of the mainshock was an E-W oriented normal faulting, and showed seismotectonic behavior compatible with the active tectonics of western Anatolia. According to the epicenter map of the aftershocks, the October 30, 2020, Samos earthquake process resulted in crust deformation over a total geographical area of 75km x 41km. The results of the seismic source propagation showed that there was no spatially or temporally correlated advance in dominant energy release observed around the mainshock hypocenter. A stable decay of aftershock activity was observed from the spatial and temporal analyses of the aftershocks that occurred within 2 months of the mainshock event. Moreover, with the proposed method of this study using the completeness plane technique to estimate the duration of aftershock activity allowed aftershocks to be estimated to last for similar to 2years. For validation, this method was applied to two previous earthquakes with different faulting mechanisms.