Recent progress in ionospheric earthquake precursor study in China: A brief review

The study of ionospheric anomaly variation before large earthquakes has attracted the attention of geophysicists for many years. This is primarily because ionospheric anomaly variation has been considered to constitute one possible method to identify earthquake precursors. Since China covers several major earthquake zones, it is critical for Chinese scientists to study possible ionospheric earthquake precursors. In this report, we provide a brief summary of recent progress in the study of ionospheric earthquake precursors mainly from Chinese mainland researchers, as well as some other scientists. This report focuses on: (1) some case studies of ionospheric abnormal behaviors before some great earthquakes around the world (e.g., M7.9 Wenchuan Earthquake, M9.0 Tohoku-Oki Earthquake, M7.0 Haiti Earthquake); and (2) some statistical characteristics of ionospheric anomalies before earthquakes, including their temporal and spatial distributions, and the relationship with the forthcoming earthquake. The above-mentioned studies may provide some new and beneficial insights for the future study of ionospheric earthquake precursors.