The final stage in the construction of the German-Indonesian tsunami early warning system

It took two years for BMKG to be chosen as the operations centre for GITEWS. GITEWS also had to be integrated into the Indonesian Tsunami Early Warning System (InaTEWS), which includes components from other donor countries. The new warning centre was opened at BMKG in Jakarta in 2008. Its operations rooms are modelled on those at DLR's German Space Operations Center in Oberpfaffenhofen. We had shown our Indonesian partners the DLR facilities and explained their functioning in 2006 with good reason. With the opening of the warning centre in 2008, a first version of the overall system went into testing mode. Although we had reached the first stage, we were still faced with a number of challenges to optimise the system.

The GITEWS system’s design is unique; it uses data from seismometers, GPS systems and tide gauges on the coasts of the Sunda Arc and its offshore islands. What makes the Indonesian location special is the proximity of the tectonic fault zone to the coast. As in Japan or off the coast of Chile, in the worst-case scenario, a tsunami can reach the mainland within a few minutes of a submarine earthquake. The complete opposite happens in the central Pacific, where a tsunami takes a very long time to reach land. While we often hear about the use of buoys in the Pacific, they are of less relevance to earthquake-induced tsunamis in Indonesia.

GFZ optimised the algorithms used to evaluate the seismic data in such a way that the location, magnitude and depth of a severe earthquake can be determined in just four minutes. GPS systems measure the horizontal and vertical shifts of the tectonic plates at the same time. Coastal tide gauges on the offshore islands show a fall in water level before a tsunami reaches the mainland.

The extremely short time available for warning and evacuating the population required a completely new approach in relation to the situational overview. This is where DLR’s contribution comes into play – the incoming data and possible scenarios are fed into the GITEWS DSS. The key task of the DSS is to compare the data stream with the scenarios and select the most probable one. This must be determined no later than four to six minutes after a powerful earthquake. Four monitors displaying well-defined content, as well as the large-screen displays, allow the officials on duty at the warning centre to have a optimum overview of what is happening. The DSS prepares all the warnings for them automatically, and groups them by coastal region and into different alert categories. It also considers risk and vulnerability models for particularly endangered coastal regions, which are created in advance using satellite data and other geospatial information. Nevertheless, humans always make the final call. If, in the opinion of the specialists, the system's recommendations are not plausible, it can be 'overruled'.

For those of us at the DLR German Remote Sensing Data Centre (Deutsches Fernerkundungsdatenzentrum; DFD) and for me, personally, this project is very special. There is no other place where geo-scientific and engineering expertise from Earth observations can be used so effectively for the wellbeing of the human population. It is also clear that this is a huge responsibility for each project collaborator at our institute. But we are confident that, by using GITEWS, we will be able to significantly reduce the number of potential victims of a large tsunami compared to 2004.

No other international project has ever pushed us like this one has. This applies to the project leaders and co-ordinators as well as all the scientists, developers and technicians involved. At DLR we have incorporated new procedures and technologies, largely with newly recruited specialists, and have converted scientific theories into real operational systems. Every step of the way we held intense technical discussions with our colleagues about the best approach. We have learned to join the different research and theoretical approaches and the 'cultures' of individual organisations and master the stages in which we faced truly difficult questions. Thanks to this, the GITEWS project team grew together, and today we can look at what we have achieved with a sense of satisfaction.

Together with the research centres involved, Germany now has what I consider to be a unique asset and one in which we should continue to invest. On the part of BMBF, I sense an appreciation of what has been achieved in the GITEWS project and enthusiasm for the possibilities that it has opened up for us. I am convinced that GITEWS will find applications beyond Indonesia. One thing is certain; at DLR, we will apply what we have learned in an international context to the management of natural disasters, the environment and resources – with significant use of Earth observation as a data source.

I am particularly proud of my inter-departmental project team at the DFD. We have now put six years of research and development under constantly intense, sometimes extreme, pressure behind us. But it was worth it. We created something essential with our partners. We will therefore help to consolidate the scientific knowledge in the coming years and optimise the system’s operation on site. However, in the medium term, it is up to our Indonesian partners to decide how the system will evolve and whether – as intended – Indonesia takes a leading role as a regional tsunami watch provider in the Indian Ocean.

When I look back, I will particularly remember the friendliness and warmth of our Indonesian partners. DFD scientists must have travelled to Indonesia more than 100 times, and we have also had the pleasure of welcoming scientists from Indonesia here about 20 times. So, it became more than a technological exchange; friendships have grown and so has mutual admiration.

At this point I would like to mention Sri Woro B. Harijono, Head of BMKG, who took responsibility in her country and seized opportunities boldly. Without her exceptional support and natural authority we would not be where we are today. We hope that the people in Indonesia will not need our system of advanced warnings for more tsunamis, but it is good to know that it exists and is in operation.