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Post-seismic Deformation Associated With the 2020 Mw7.0 Samos (Eastern Aegean Sea) Earthquake

Description: 

Large earthquakes not only result in substantial static co-seismic deformation but also include time-dependent post-seismic deformation as stress is redistributed and propagates through the surrounding medium. This study investigates the post-seismic deformation associated with the 30 October 2020 Mw7.0 Samos earthquake (eastern Aegean Sea) using a combination of GNSS and InSAR observations. Although the seismic sequence has been extensively studied from various perspectives, its post-seismic deformation remains underexamined. We analyzed the spatiotemporal evolution of post-seismic deformation and assessed the productivity and total duration of the aftershock sequence to better elucidate the interplay between fault slip and seismicity. To this end, GNSS observations from stations surrounding the affected area were processed using the Precise Point Positioning technique, isolating the post-seismic signal while accounting for the background tectonic motion and noise. InSAR data for the same period were analyzed using the Persistent Scatterers Interferometry technique. To model the post-seismic transient signals, we fitted the displacement time series using a stretched exponential function that captures both the rapid onset of afterslip and the prolonged post-seismic processes contributing to the long-lasting deformation. A joint inversion of both datasets was conducted to explore the properties of post-seismic slip and its relationship with co-seismic slip and aftershock activity. Our analysis reveals evidence of shallow afterslip in regions surrounding the co-seismic slip area, thereby releasing a substantial post-seismic moment budget. At the same time, afterslip was sustained within the main-shock rupture zone, highlighting the slow recovery of fault locking in that region. Overall, the findings provide insights into the spatiotemporal dynamics of post-seismic deformation and contribute to a better understanding of fault behavior following large earthquakes. This work also underscores the importance of combining geodetic and seismological data for resolving post-seismic processes.

Session: SSJ-SSOC-SSA Joint Session: From Slow to Fast Earthquakes: Bridging the Spectrum of Fault Slip [Poster]

Type: Poster

Date: 4/16/2026

Presentation Time: 08:00 AM (local time)

Presenting Author: Pavlos Bonatis

Student Presenter: Yes

Invited Presentation: 

Poster Number: 141

Authors