The JRC´s tsunami assessment modelling system includes four main components:
1) The Global Tsunami Scenario Database (GSD) is a set of 136 000 calculations performed using a theoretical model, with epicentres established around historical tsunami events. Calculations for earthquake magnitudes between 6.5 and 9.5 have been performed. The database provides a preliminary, immediate, estimate of tsunami consequences as soon as the real earthquake epicentre is known. The scenario database identifies the locations potentially affected as well as the predicted wave height.
2) The Tsunami Online Calculation System (OCS) uses the same model as the scenario database, but it is automatically initialised with the real earthquake parameters (epicentre and magnitude). The calculations start as soon as an earthquake with potential tsunami consequences is identified and the calculation time is in the order of 30–40 minutes.
3) The Tsunami Analysis Tool is a piece of software developed by the JRC to allow a proper analysis of Tsunami events in real time, during their occurrence, in order to give the possibility to quickly estimate the real potential consequences of a Tsunami; the objective is therefore to prepare to launch Warning Messages.. The software allows the direct comparison of scenario databases (GSD) or online calculations (OCS) with sea level measurements in real time though international channels.
4) The Tsunami Alerting Device (TAD) has been designed for installation in tsunami prone coastal areas. The TAD delivers warning messages to the population at risk in the quickest possible time. A prototype is currently operating in Setubal (Portugal). The TAD consists of a panel equipped with data receivers, a display, an alerting siren and a loudspeaker. It can be automatically activated by the GDACS system or can be connected with existing local sea level measurement systems. This allows the device to activate the alarm also in the case of dangerous waves of non-seismic origin such as those created by landslides.
Tsunamis are among the natural hazards that can result in the largest number of victims in single events. Only in recent years, Tsunamis caused more than 250 000 casualties in the Indian Ocean in 2004 and more than 25 000 in Japan in March 2011.
While the earthquakes that cause them cannot be predicted, it is possible to provide early warning about tsunamis if the distance between the seismic source and the coast is not too short. After the Indian Ocean disaster in 2004, the JRC has developed a system that uses sophisticated seismic and hydraulic modelling coupled with communication technologies to alert the humanitarian operators or Civil Protection bodies about tsunamis.
Today, the “official” Tsunami warning systems, developed in the frame of UNESCO-IOC (Integovernmental Oceanographic Commission) rely only on seismic signals and provide information on the arrival times of the tsunami wave along coastal areas. Other National Systems are more advanced: for example the Japanese national tsunami warning system relies on pre-calculated tsunami scenarios, allowing it to issue a first alert within 3 minutes of an earthquake that scores more than 6.5 on the Richter scale.