Integrated Multi-Parameter Precursory Signatures in the Preparation Phase of Large Earthquakes

Understanding how significant earthquakes prepare and initiate requires examining processes beyond tectonic loading alone. In this study, we integrate seismic, oceanic, atmospheric and ionospheric observations to investigate multi-parameter anomalies that systematically precede major earthquakes in diverse tectonic environments. Long-term seismic indicators, including seismicity pattern, reveal progressive fault locking and asperity development within rupture-prone zones. The lithospheric changes coincide with transient environmental perturbations such as sharp fluctuations in sea surface height and temperature, atmospheric pressure and temperature variability, ozone and cloud parameter anomalies and pronounced ionospheric total electron content (TEC) disturbances. The spatial overlap of these anomalies with regions of high co-seismic slip suggests that external environmental forcing, particularly transient oceanic loading and atmosphere–ionosphere coupling may amplify stresses on critically loaded fault segments. Our results highlight a consistent preparatory pattern characterized by long-term stress buildup, short-term seismic acceleration and synchronous environmental anomalies. This integrated framework underscores the importance of multi-domain monitoring systems and demonstrates the potential of coupled external–internal stress perturbations to contribute to rupture triggering in large earthquake-generating faults. By identifying cross-domain precursory signals, this approach enhances our capacity to recognize long-term and short-term indicators of impending large earthquakes, offering valuable insights for early-warning initiatives, improved hazard assessment and reducing societal risk in vulnerable regions.