Recent Developments in Understanding Natural-Hazards-Generated TEC Perturbations: Measurements and Modeling Results

Natural hazards including earthquakes, volcanic eruptions and tsunamis have been significant threats to humans throughout recorded history. Global navigation satellite systems (GNSS; including the Global Positioning System (GPS)) receivers have become primary sensors to measure signatures associated with natural hazards. These signatures typically include GPS-derived seismic deformation measurements, co-seismic vertical displacements and real-time GPS-derived ocean buoy positioning estimates. Another way to use GPS observables is to compute the ionospheric total electron content (TEC) to measure, model and monitor post-seismic ionospheric disturbances caused by e.g., earthquakes, volcanic eruptions and tsunamis. In this paper, we discuss new applications using examples of recent natural hazards that generated TEC perturbations. We present results for state-of-the-art imaging using ground and space-based ionospheric measurements and coupled atmosphere-ionosphere modeling of ionospheric TEC perturbations. Our study strongly suggests that both ground-based and space-borne GPS remote sensing techniques could play a critical role in detection and imaging of the upper atmosphere signatures of natural hazards including earthquakes, tsunamis, and volcanic eruptions. The GNSS-based remote sensing of natural-hazard induced ionospheric disturbances could potentially be applied to operational tsunami and earthquake early warning systems.