IonKit-NH: A MATLAB-based toolkit for ionospheric detection of earthquake, tsunami and volcanic eruption

In recent years, GNSS-derived total electron content (TEC) measurements have emerged as an effective method for detecting natural hazards through their ionospheric manifestations. Seismo-atmospheric disturbances generated by earthquakes, tsunamis, and volcanic eruptions propagate as traveling ionospheric disturbances (TIDs) that modify ionospheric electron density. Despite this potential, specialized open-source tools for such analyses remain limited. We present IonKit-NH, a MATLAB-based toolkit enabling systematic processing of multi-GNSS data (GPS, GLONASS, Galileo, BDS) through dual-frequency combination analysis for TEC derivation. The software implements automated generation of time-distance diagrams and 2D TEC perturbation maps, enabling quantitative characterization of TID propagation parameters associated with natural hazards. This toolkit enhances standardized analysis of ionospheric precursors and co-seismic signals across global navigation satellite systems.