Ionospheric Detection of Natural Hazards: Maturity and Perspectives

Abstract:

Natural Hazards (NH), such as earthquakes, tsunamis, volcanic eruptions, and severe tropospheric weather events, generate acoustic and gravity waves that propagate upward and cause perturbations in the atmosphere and ionosphere. The branch of Geophysics that studies NH-associated ionospheric disturbances is often called “Ionospheric Seismology”, or “Seismology without seismometers”. The birth of this discipline goes back in time into the 1960-ies, when several research groups detected ionospheric perturbations associated to the great Alaska Mw9.2 earthquake of March 1964. During the last two decades, with the development of the GNSS and networks of ground-based GNSS-receivers, it has been demonstrated that earthquakes, volcanic eruptions, tsunamis, severe weather events, etc., are regularly detected in the ionosphere.

The modern Ionospheric Seismology includes not only detection of NH-driven ionospheric perturbations and analysis of their main features, but also the development of ionosphere-based methods of localization of NH source. In addition, recent results show the possibility to determine the NH source parameters from the ionosphere. For instance, earthquake-driven ionospheric disturbances (called co-seismic ionospheric disturbances, CSID) first occur just above the seismic source. Therefore, knowing the time and the coordinates of the first CSID arrivals it is possible to obtain the position and the extent of the source. Similarly, from tsunami-driven ionospheric disturbances it is possible to estimate the tsunami wave height.

This contribution will present an overview of the recent developments in the area of ionospheric detection of earthquakes, tsunamis and volcanic eruptions, and will discuss the future perspectives for this novel discipline.