Ionospheric Response to the 2022 Ya'an Earthquake in China

Earthquake induced ionospheric disturbances have become an important topic in earthquake prediction and monitoring research. On June 1, 2022, a magnitude 6.1 earthquake struck Ya'an, Sichuan, China. This study analyzes the changes in Total Electron Content (TEC) before and after the earthquake using GNSS (Global Navigation Satellite System) observational data, and investigates the ionospheric disturbances triggered by the earthquake and their possible mechanisms. We utilized GNSS station data from the Sichuan region to examine the TEC variations before and after the earthquake. The results reveal significant TEC anomalies within 150 km of the epicenter in the first hour following the earthquake, with a maximum change of up to 30% compared to the pre-earthquake background value. Notably, the TEC changes in the immediate vicinity of the epicenter showed a rapid increase followed by a swift decay, exhibiting clear temporal and spatial dependencies. Additionally, short-term ionospheric TEC fluctuations were found to correlate with atmospheric pressure changes. To further investigate the source of these disturbances, this study also combined meteorological and geomagnetic data observed during the earthquake. We found that the ionospheric disturbances might be closely related to the propagation of seismic-induced atmospheric pressure waves reaching the ionosphere. Furthermore, we applied numerical simulations to describe how these pressure waves could affect the ionospheric electron density, leading to changes in TEC. This study provides new empirical data on earthquake-induced ionospheric disturbances and reveals a possible coupling mechanism between earthquakes and the ionosphere. By integrating GNSS TEC data with meteorological and geomagnetic observations, this research offers new methods and theoretical support for ionospheric monitoring.