Tsunami observation and simulation
TOAST (Tsunami Observation And Simulation Terminal) is a software for tsunami simulation and verification giving a quick hazard assessment. The results can be verified by oceanographic sensors such as tide gauges or buoys. TOAST is developed by gempa GmbH, a spin-off from GFZ Potsdam (developer of the real-time earthquake processing and analysis system SeisComP3). Gempa is part of the SeisComP3 development group and is working within the German Indonesian Tsunami Early Warning System (GITEWS) project.
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 the perfect complement to SeisComP3 for the implementation of a fully functional tsunami warning system. TOAST is 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 on any atypical events, for example earthquakes in unconsidered areas or earthquakes with untypical rupture mechanisms. Additional to this on the fly simulation simulation TOASTs flexible simulation interface also allows integration of existing pre-calculated scenario databases.
Simulated Tsunami wave propagation of M8.0 event in Makran Subduction Zone
TOAST connects to a SeisComP3 system and listens to the incoming earthquake parameters. In case a hypocenter and magnitude arrives, TOAST uses a Wells & Coppersmith (1984) formula to generate the rupture size based on magnitude. By default the rupture area is centered around the epicenter, and the strike and dip information is derived from pre-configured fault information. Once the rupture area is generated the simulation plug-ins are triggered.
By default EasyWave, an on the fly simulation, is used. But plug-ins for different simulation algorithm also exist including plug-ins for pre-calculated tsunami databases. The rupture area can be placed at several pre-configured positions relative to the hypocenter and simulations for several positions can be calculated on the fly in parallel. As the earthquake information is changing over time, with each relevant update new simulations are triggered automatically. But also rupture areas can be generated manually and simulations using these can be started.
TOAST provides different perspectives showing the results of the simulation. They show the following features:
To verify the simulation results, TOAST provides a manual tsunami onset picker, which allows to pick 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 it compares the simulation information with the actual earthquake information.