Physical and Statistical Pattern of the Thiva (Greece) 2020-2022 Seismic Swarm

Area of Science:

• Geophysics
• Seismology
• Statistical Physics

Background:

• A significant earthquake swarm occurred near Thiva, Greece, from December 2020 to mid-2022.
• The swarm exhibited complex spatiotemporal migration patterns, necessitating advanced analytical methods.
• Understanding the underlying physical and statistical processes is crucial for seismic hazard assessment.

Purpose of the Study:

• To analyze the statistical and physical patterns of the Thiva earthquake swarm.
• To identify and characterize spatiotemporal seismicity clusters using objective methods.
• To investigate the driving mechanisms behind the evolution of identified seismic clusters.

Main Methods:

• Relocation of seismicity using HypoDD for precise event localization.
• Application of the DBSCAN clustering algorithm to identify spatiotemporal seismic clusters.
• Analysis of cluster properties using Non-Extensive Statistical Physics (NESP) and the fragment-asperity model.

Main Results:

• The DBSCAN algorithm successfully identified distinct seismicity clusters within the swarm.
• NESP analysis revealed statistical patterns consistent with Q-exponential distributions (qD: 0.7-0.8, qT: 1.44-1.50).
• The first cluster (WNW) was primarily driven by afterslip, while the second (ESE) exhibited normal diffusion.

Conclusions:

• NESP effectively interprets the complexity and non-additive nature of earthquake swarm evolution.
• DBSCAN is a valuable tool for uncovering spatiotemporal clustering in seismic activity.
• The identified physical mechanisms provide insights into the dynamics of the Thiva earthquake swarm.