Pre-seismic anomalies and co-seismic disturbance induced by the 2024 Mw 7.1 Wushi earthquake: multi-GNSS observations and modeling

Abstract

This study investigates ionospheric anomalies associated with the Mw 7.1 Wushi earthquake that occurred in Xinjiang, China, on January 22, 2024. We analyze multi-GNSS data, including GPS and BeiDou (BDS), from the Crustal Movement Observation Network of China (CMONOC) to detect pre-seismic ionospheric anomalies and co-seismic ionospheric disturbances (CIDs). A 27-day sliding interquartile range method is applied to BDS geostationary satellite data to identify pre-seismic anomalies while minimizing the influence of solar and geomagnetic activity. The results show that BDS geostationary satellites significantly improve the spatiotemporal resolution of ionospheric monitoring, and M_GIM outperforms CODE-TEC in regions with sparse IGS stations. Pre-seismic anomalies are observed on January 14, 15, 16, and 18, with those southeast of the epicenter possibly caused by additional electric fields generated in the seismic preparation zone. CIDs are detected within 400 km of the epicenter using the Butterworth filtering technique, revealing a propagation speed of approximately 1 km/s, likely caused by acoustic-gravity waves generated by the earthquake. This study demonstrates the importance of multi-GNSS observations and high-resolution regional modeling for detecting and understanding seismo-ionospheric anomalies, providing insights into the earthquake preparation process and ionospheric disturbance propagation characteristics.

Keywords

• Pre-seismic anomalies
• co-seismic ionospheric disturbances
• multi-GNSS
• regional ionospheric modeling
• BeiDou (BDS)