The Preparatory Phase of the 2023 Kahramanmaraş (Turkey) Major Earthquakes: A Multidisciplinary and Comparative Analysis

On 6 February 2023, Turkey experienced its most powerful seismic event in over 80 years, with a moment magnitude (Mw) of 7.7, followed just nine hours later by a second large earthquake with Mw 7.6. Both events struck the Kahramanmaraş province in southeastern Turkey, within the complex tectonic setting of the East Anatolian Fault Zone (EAFZ), causing widespread destruction and significant loss of life. According to lithosphere–atmosphere–ionosphere coupling (LAIC) models (e.g. Pulinets and Ouzounov, 2011), large seismic events are expected to generate a cascade of anomalies across various geophysical layers, from the lithosphere through the atmosphere to the ionosphere, as part of the earthquake preparation process. This multidisciplinary study investigates the preparatory phase of these two major earthquakes by identifying potential precursors and disturbances across these layers, in order to better understand the mechanisms linking the geospheres prior to seismic events.

Our comprehensive analysis (De Santis et al., 2019) draws on multiple datasets, including ground-based and satellite observations, to detect anomalous variations in parameters such as ground surface temperature, atmospheric gases, ionosphere electron density and geomagnetic field. These anomalies show a cumulative occurrence with an accelerating trend (De Santis et al, 2017), either exponential or power-law in nature, in the days and weeks preceding the mainshock. The anomalies predominantly exhibit an upward progression from the lithosphere  through the atmosphere to the ionosphere, revealing a chain of interconnected processes within these geospheres during the earthquake preparation phase.

Our findings suggest that these anomalies provide valuable evidence in support of a two-way coupling model, where disturbances can propagate upward from the lithosphere. Additionally, the study highlights the potential role of fluid chemistry (Calcara, 2022), particularly the release of gases such as radon, in driving these coupling processes

In conclusion, this study underscores the significance of a multidisciplinary approach to investigating earthquake precursors across the Earth system. The identification of consistent patterns in pre-earthquake anomalies can enhance our understanding of the complex interactions within the lithosphere-atmosphere-ionosphere system and could contribute to the development of more effective early-warning systems for major seismic events.

References

Pulinets, S.; Ouzounov, D. Lithosphere-atmosphere-ionosphere coupling (LAIC) model-an unified concept for earthquake precursors validation. J. Asian Earth Sci. 2011, 41, 371–382

De Santis, A.; Abbattista, C.; Alfonsi, L.; Amoruso, L.; Campuzano, S.A.; Carbone, M.; Cesaroni, C.; Cianchini, G.; De Franceschi, G.; De Santis, A.; et al. Geosystemics View of Earthquakes. Entropy 2019

De Santis A. et al., Potential earthquake precursory pattern from space: the 2015 Nepal event as seen by magnetic Swarm satellites, Earth and Planetary Science Letters, 461, 119-126, 2017

Calcara, M. Chemistry in earthquake: The active chemical role of liquid and supercritical waters in microfracturing at depth. J. Seismol. 2022, 26, 1205–1221