Lithospheric magnetic variation based on a 3D surface spline model compared with strong earthquake occurrence at the Tibetan Plateau

The National Geophysical Data Center (NGDC) of the United States collected aeromagnetic data for input into a series of geomagnetic models to improve the resolution, but in the Tibetan Plateau region the ground-based observation data are missing and do not clearly reflect the characteristics of lithospheric magnetism. In this study, we evaluate the lithospheric magnetism of the Tibetan Plateau by using a 3D surface spline model and the observation of >200 newly constructed stations to determine the spatial distribution of plateau geomagnetism, as well as its correlation with the tectonic features of the region. We analyze the relationships between M ≥ 5 earthquakes and the lithospheric magnetic field variation at the Tibetan Plateau, and identify regions susceptible to the occurrence of strong earthquakes. We compare the geomagnetic results with those from an enhanced magnetic model (EMM) and shed light on improving the lithospheric magnetic field calculation in the Tibetan Plateau region. Further research reveals that this magnetic anomalies exhibit distinct differences from magnetic-seismic correlation mechanisms observed in other tectonic settings. It is primarily governed by the combined effects of compressional magnetism, thermal magnetism, and deep thermal-stress condition. This study provides new evidence and physical interpretation for identifying seismic hazard zones on the Tibetan Plateau using geomagnetic anomalies.