Tsunami observation and simulation
During the development of the GITEWS software used by BMKG in Jakarta it soon became apparent that the system was complex and specialized to an extent which made it hard to offer to other institutes. Therefore gempa started the development of TOAST, a very flexible tsunami early warning software with high scalability.
TOAST is perfectly complementing SeisComP for the implementation of a fully functional tsunami warning system. TOAST is fully optimized for its application: Tsunami Early Warning. While conventional tsunami early warning systems are based on huge databases of pre-calculated scenarios. By default TOAST uses an on-the-fly simulation approach. Because of this approach TOAST can react to any atypical events, for example earthquakes in unconsidered areas or earthquakes with atypical rupture mechanisms. Additional to this on-the-fly simulation, TOAST’s flexible simulation interface also allows integration of existing pre-calculated scenario databases.
By default EasyWave is used for on-the-fly tsunami simulation. In addition, plugins exist for reading different pre-calculated tsunami databases. Such databases are generated by external software such as TsunAWI.
The earthquake rupture area can be placed at multiple pre-configured positions relative to the hypocenter and simulations for several positions can be calculated on the fly in parallel. As the earthquake information change over time, new simulations are triggered automatically with each relevant update. The rupture areas can also be generated manually and simulations using these can be started.
TOAST provides different perspectives showing the results of the simulation. They comprise the following features:
To verify the simulation results, TOAST provides a manual tsunami onset picker. It allows to pick tsunami onsets, amplitudes and periods based on real-time tide gauge observations. The observed information is then used to calculate a scenario quality which represents how well the simulated and observed values match.
For example the quality of the oceanographic sensors is indicated by the color of the tide gauge symbol in the simulation widget. The simulation widget shows these quality parameter not only for the tide gauge data, but also for epicenter location, depth, magnitude, comparison with pre-configured rupture mechanisms and existing moment tensors. The quality information can change with time as TOAST compares the simulation information with the updated earthquake and tsunami information.
TOAST is in use world-wide. Videos and images generated by TOAST are not only used at data centers but also broadcasted to the public by news channels. Watch how tsunami simulations by TOAST have impacted the tsunami alerts made available after the M7.5 earthquake in the Flores Sea, Indonesia, on 14 December, 2021.