Geodetic analysis for investigating possible seismo‐ionospheric precursors related to the Ain Témouchent earthquake of December 22, 1999, in NW Algeria

Abstract

The main aim of this research focuses on the seismo-geodetic data integration to identify the origin-time of seismic precursors through the ionospheric total electron content (TEC) parameter. The case study concerns the moderate-sized earthquake (Mw = 5.7) that occurred in Ain Témouchent-northwestern Algeria on December 22, 1999. The adopted approach is to reproduce the Global Positioning System (GPS)_TEC time-series signal in order to identify large-amplitude electron density perturbations in the ionized layer of the Earth’s atmosphere. Thus, we propose an analytical and interpretive method to identify the seismo-ionospheric precursor occurrence time of the polarized signal during the earthquake preparation phase. For this purpose, the use of geodetic data derived from signal processing of dual-frequency permanent ground-based GPS/Global Navigation Satellite Systems (GNSS) receivers allowed us to identify ionospheric disturbances preceding the triggering of the mainshock. Furthermore, modeling the time occurrence of aftershocks revealed a strong correlation exists between the seismo-ionospheric precursors and the main aftershocks. Space geodesy techniques integrated into seismic networks achieve valuable enhancement to reinforce the Earthquake and Tsunami Early Warning System.