From Sumatra 2004 to Tohoku-Oki 2011: what we learn about Earthquake & Tsunami detection by ionospheric sounding.

Speaker: Giovanni Occhipinti aka Ninto
The recent tsunamigenic Tohoku earthquake (2011) strongly affirms, one time more, after the 26 December 2004, the necessity to open new paradigms in oceanic monitoring. Detection of ionospheric anomalies following the Sumatra earthquake tsunami (e.g., Occhipinti et al. 2006, 2008, 2010) demonstrated that ionosphere is sensitive to earthquake and tsunami propagation: ground and oceanic vertical displacement induces acoustic-gravity waves propagating within the neutral atmosphere and detectable in the ionosphere. Observations supported by modelling proved that tsunamigenic ionospheric anomalies are deterministic and reproducible by numerical modelling (Occhipinti et al., 2006, 2008) via the ocean/neutralatmosphere/ionosphere coupling mechanism. To prove that the tsunami signature in the ionosphere is routinely detected I show here perturbation of total electron content (TEC) measured by GPS and following tsunamigenic eartquakes from 2004 to 2010 (Rolland et al. 2010), nominally, Sumatra (26 December, 2004 and 12 September, 2007), Chile (14 November, 2007), Samoa (29 September, 2009) and the recent Tohoku-Oki (11 Mars, 2011). In addition to GPS/TEC observations close to the epicenter and measured by GEONET network, new exciting measurements in the far field were performed by Airglow measurement in Hawaii; those measurements show the propagation of the IGWs induced by the Tohoku tsunami in the Pacific Ocean (Occhipinti et al., 2011). Based on the observations close to the epicentre, mainly performed by GPS networks located in Sumatra, Chile and Japan, we highlight the TEC perturbation observed within the first hour after the seismic rupture. This perturbation in the ionosphere contains information about the ground displacement, as well as the consequent sea surface displacement resulting in the tsunami. In this talk we present all this new tsunami obsevations in the ionosphere and we discuss, under the light of modelling, the potential role of ionospheric sounding in the oceanic monitoring and future tsunami warning system by GPS, Airglow and OTH radar (Coisson et al., 2011). All ref. mentioned in this abstract are available at