Pre-seismic anomaly analysis of the Turkey earthquakes on 6 February 2023 based on multi-source satellite observations

On 6 February 2023, the destructive earthquakes (EQs) occurred in Kahramanmaras Turkey with the maximum magnitude 7.8. In this paper, based on multi-source satellite observations, we investigated the pre-seismic anomalies of infrared radiation and ionosphere, and analyzed the coupling features of multi-parameter anomalies in temporal evolution and spatial distribution. Analysis results indicated that in the vicinity of the epicenter, the outgoing longwave radiation (OLR) anomalies observed from NOAA-18 satellite were very obvious in January 2023, and the ionospheric plasma anomalies observed from CSES and SWARM satellites were significantly detected on 30 January 2023, which were probably the precursor signals of the impending main shock. Combined with the analysis results of crustal deformation and atmospheric compositions for the Turkey EQs in published articles, we believed that crustal stress changes and rock ruptures in the boundaries between the Arabian and African plates and the Anatolian block were more likely to cause the pre-seismic anomalies in infrared radiation, atmosphere and ionosphere. The observed anomalies had a clear coupling relationship, and represented the stage changes of seismogenic process for the Turkey EQs. In addition, the satellite remote sensing technology is very helpful for us to monitor the multi-parameter variations in lithosphere, atmosphere and ionosphere, better verify the correlation of pre-seismic anomalies in Earth's multi-sphere structures, and further promote the research on the multi-sphere anomaly coupling mechanism.