The GITEWS Tsunami Simulation System based on Multi-Sensor Inversion

The German Indonesian Tsunami Early Warning System (GITEWS) comprises a sophisticated interaction of online sensor data, simulation-based inversion, and modeling result interpretation to provide qualified and accurate tsunami warning within extremely short time. In order to provide accurate inversion capabilities for near-field tsunamis, the simulation system (SIM) within the GITEWS tsunami early warning system relies on simultaneous evaluation of multiple sensors. In order to provide quick situation assessment, it relies on a large number of pre-computed tsunami scenarios. In order to reliably invert and select a reasonable scenario from incoming sensor data the following prerequisites have to be fulfilled: pre-computed scenarios need to be accurate and realistic; different data types need to be related with each other; different data types need to complement each other as to minimize uncertainty and ill-posedness. In order to address these topics, a new tsunami modeling approach has been developed, including an unstructured mesh finite element tsunami inundation and propagation model. A new scenario selection method has been developed, which interprets different types of data (seismic parameters, wave height and wave arrival time, earth crust deformation vectors) simultaneously, using physical modeling and a generalized distance measure to relate these data. It can be shown that this simultaneous evaluation of complementary data leads to reliable and quick inversion results. Equipped with this novel inversion method, a fully automatic simulation system forms the engine of the GITEWS early warning system. Without human interaction, it is capable of performing the matching of incoming data with existing scenarios as well as post-processing and formatting simulation results like mapped data and virtual sensor data