The variometric approach to real-time high-frequency geodesy

• Published in: Atti della Accademia nazionale dei Lincei. Rendiconti Lincei. Scienze fisiche e naturali Vol. 29; no. Suppl 1; pp. 95 - 108
• Main Authors: Fratarcangeli, F., Ravanelli, M., Mazzoni, A., Colosimo, G., Benedetti, E., Branzanti, M., Savastano, G., Verkhoglyadova, O., Komjathy, A., Crespi, M.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.06.2018; Springer Nature B.V
• Subjects: Biomedicine; Disturbances; Earth and Environmental Science; Earth Sciences; Earthquakes; Emergency warning programs; Environment; Geodesy; Geodetics; Geological hazards; Geophysics; Global navigation satellite system; History of Science; Information retrieval; Ionosphere; Life Sciences; Navigation; Navigation satellites; Real time; Satellite observation; Satellite Positioning for Geosciences; Seismic activity; Seismology; Total Electron Content; Tsunamis; GNSS seismology; Ionospheric disturbances; High-frequency geodesy; Variometric approach; Tsunami early warning
• ISSN: 2037-4631; 1720-0776
• DOI: 10.1007/s12210-018-0708-5

High-frequency geodesy is here intended as the capability of retrieving information relevant to geodesy and geophysics at high frequency through geodetic measurements and methodologies. In particular, this short review work focuses on two aspects: fast ground motions, as those due to earthquakes, and fast ionospheric total electron content (TEC) disturbances, as those caused by tsunamis. This information can be retrieved, even in real time, from Global Navigation Satellite System observations collected at high rate (equal or higher than 1 Hz), and can significantly support geohazard understanding contributing in seismic moment estimation and tsunami early warning. Here, the real-time possibilities of the new variometric approach for high-frequency geodesy are summarized: the fundamental idea is to directly focus on the quantities of interest, which are “variations” (of positions, of ionospheric TEC) and can be properly estimated in real time. The work moves “from ground to ionosphere”: with respect to the ground, the more consolidated application of the variometric approach to GNSS seismology (VADASE) is presented, up to the latest developments; with respect to the ionosphere, the brand new application named VARION for TEC disturbances computation is described, and the first results of the application to the Illapel, Chile earthquake (USGS M = 8.3 , 16 September 2015, 22:54:32 UTC) are shown.