Lithosphere–Coversphere–Atmosphere–Ionosphere Coupling with the 2023 Turkey Earthquake Doublet: A Deviation–Time–Space–Frequency Analysis

Abstract. The prerequisite of extracting reliable earthquake precursors from multi-parameter observations is still a challenge because of high false anomalies in the traditional analysis techniques. The given limitation is partly mitigated by a novel criterion of Deviation–Time–Space–Frequency (DTSF) anomaly detection on the 2023 Turkey earthquake doublet (Mw 7.8, Mw 7.5). The DTSF criterion builds on Deviation-Time-Space (DTS) analysis, where an anomaly must meet four rigorous criteria: statistical significance of greater than 15–day baselines of greater than ±1.4σ, quasi-synchronous activation, spatial association with geosphere-specific manifestation zones as well as frequency-domain validation in the form of band-specific power enhancement, cross-layer coherence of ≥0.5, and physically consistent phase relationships. Microwave brightness temperature (MBT), surface latent heat flux (SLHF), outgoing longwave radiation (OLR), total electron content (GPS-TEC, GIM TEC), and electron density/temperature (Ne, Te) under geomagnetically quiet conditions are analyzed. Results demonstrate the significance of the enhanced DTSF anomaly extraction approach in two aspects. First, the systematic vertical coupling sequence between the lithospheric stress and ionospheric perturbations through four temporal stages by rough estimations of the wavelet coherence analysis and phase–lag evaluations. SLHF precedes TEC by 2.5±0.3 days (C=0.71) and OLR by 1.2 ± 0.2 days (C=0.61) during pre-seismic phases; co-seismic coupling exhibits same-day MBT-TEC coherence (C=0.70–0.85), distinguishing impulsive seismic forcing from gradual processes. Second, the frequency criterion is a high-pass filter of credible anomalies that rejects noise in meteorological and space weather applications better than the DTS analysis that would falsely identify a precursor. For this case study, DTSF criterion achieved a detection rate of 89 % with 8 % false positives, 85 % reduction in false anomalies compared to conventional criteria. This case-specific study demonstrates the potential of the DTSF approach for validating Lithosphere–Coversphere–Atmosphere–Ionosphere (LCAI) coupling chain, which may promote the development of synergistically multi–parametric identification of earthquake precursors, while validation remains pending across additional earthquake cases.