This chapter reviews new and innovative techniques for detecting and monitoring natural and man‐made hazards by measuring Earth’s ionosphere total electron content (TEC) perturbations generated by the events, using a global network of ground‐based and spaceborne assets. State‐of‐the‐art retrievals of hazard‐related geophysical parameters, including tsunami wave height and ground surface displacement, are explained using TEC observations. The results for imaging and modeling of ionospheric TEC perturbations in a dynamically coupled atmosphere–thermosphere–ionosphere system are presented and new perspectives discussed.
The use of sophisticated first‐principles physics‐based ionosphere models, together with ground‐ and space‐based observations of Earth’s ionosphere, has greatly advanced the understanding of the propagation properties of the ionospheric TEC perturbations generated by natural and man‐made hazardous events. The progress made offers an opportunity for the seismic‐ionospheric community to devise and develop early warning systems and new ground‐ and space‐based technologies that could potentially save human lives and minimize material damage.