Joint Analysis of Shannon and Tsallis Entropy and GRACE-FO driven Equivalent Water Height Anomalies for Pre- and Post-Rupture Monitoring: An Example of the 2023 Mw = 7.8 Kahramanmara\c{s} Earthquake, T\"urkiye

Abstract

In order to understand the variations in fault systems throughout the seismogenic cycle, mechanical states and the complexities of seismic interactions must be considered. In this study, we present a data integration framework combining a 25-year seismic catalog with Equivalent Water Height (EWH) datasets from the GRACE-FO mission and two information-theoretic complexity measures (Shannon and Tsallis entropy) to examine spatiotemporal changes in the East Anatolian Fault System associated with the 2023 Kahramanmara\c{s} earthquake doublet. The pre-rupture period exhibits a systematic increase in the entropy measures alongside a gradual decrease in EWH, suggesting a transition towards fault network criticality driven by segment fragmentation, long-range correlations, poroelastic contraction, fluid migration, and progressive stress accumulation. During the co-seismic phase, we observe an abrupt increase in entropy with a corresponding negative shift in EWH. In the post-seismic period, the persistence of elevated entropy and EWH anomalies indicates that the fault system remains in a non-equilibrium state dominated by aftershock clustering, fault zone damage, permeability changes, and viscoelastic relaxation. Additionally, structured computational workflows detailing these joint methodologies are provided via the Seismic Entropy Analysis (Algorithm 1) and the Relationship Between Tsallis q and Gutenberg-Richter b-value (Algorithm 2) pseudo-codes, facilitating the direct reproduction and regeneration of all results.