GO-EUREKA: GNSS-observation based European system for earthquake and tsunami risk assessment in near-real-time 

A tsunami is one of the most powerful and destructive natural hazards. Tsunamis occur in a result of a sudden and large displacement of the ocean that, in turn, are mostly caused by large submarine earthquakes. Tsunami hazard risks are assessed based on the following set of parameters: 1) seismic source dimensions and the amplitude of the co-seismic crustal uplift to infer the tsunamigenic potential of an earthquake; 2) the wave heights and the speed of a tsunami propagating in the open ocean. However, despite recent developments, the near-real-time (NRT) monitoring and forecasting of both local (800 km from the source, and trans-ocean propagation) tsunamis remain very challenging. As of today, even the most advanced seismo-geodetic methods still fail to estimate the tsunamigenic potential for large (Mw>8) earthquakes. In response to these fundamental challenges, since 2022, we have been developing a GNSS-observation-based European system for earthquake and tsunami risk assessment “GO-EUREKA”. GO-EUREKA will use quasi-continuous observations of GNSS-based ionospheric total electron content (TEC) from ground-based and ship-based dual-frequency GNSS-receivers in order to assess earthquake and tsunami related hazards. The data will be collected and pre-processed by the module ALTRUIST (PI-M. Ravanelli). Further, the following steps will be performed for the NRT assessment of tsunami hazards: 1) automatic detection of co-seismic and co-tsunamic ionospheric disturbances (CSID and CTID, respectively); 2) confirmation of the origin of the detected disturbances; 3) inversion for earthquake magnitude and co-seismic crustal uplift from CSID (for the near-field); 4) inversion of tsunami wave heights and the propagation speed based on analysis of features of CTID (for the far-field). This contribution will present recent developments in the field of NRT tsunami hazard assessment from the ionospheric observations, including the NRT detection of CSID/CTID, NRT estimation of propagation speed of CSID/CTID, confirmation of the link between the detected disturbances and earthquakes/tsunamis, by newly developed rapid simulation tools for CSID, and by NRT-compatible identification of the source of ionospheric disturbances.