Are tsunamis common in Hawaii?

Questions and answers about the tsunami early warning system

1. How does the tsunami early warning system work in Indonesia?
2. How does this early warning system differ from what is already in use in the Pacific and why has it not been used?
3. Why was no early warning system deployed in the Indian Ocean before December 26, 2004?
4. How much does it cost to set up the system alone?
5. How will the system be financially supported in the long term?
6. How is the permanent system functionality guaranteed?
7. What happens if some sensors fail?
8. What other fail-safe safeguards are there?
9. How is the early warning system prevented from detecting a simple tidal wave as a tsunami?
10. How are the sensors protected against vandalism?
11. The early warning system registers a tsunami threatening the coast. What is the procedure in such a situation to warn or possibly evacuate the coastal population?
12. You cannot evacuate a city within 20 minutes. Doesn't that mean the system is actually useless?
13. Which channels are used to pass on warnings of a tsunami to the population?
14. How can false positives be avoided?
15. Are there disaster plans that include e.g. escape routes?
16. Are children informed at school about how to behave in an emergency?
17. How much time is there between the warning and the arrival of the tsunami, so how much time is there to escape?
18. Which personnel does the early warning system require?
19. How long does it take to train this staff?
20. How will the population be supplied with medicines, food and drinking water after a disaster if the infrastructure has collapsed?
21. How many countries or research institutes worldwide have worked on the development and / or installation of the early warning system?
22. How important is international cooperation to protect against natural disasters and especially tsunami?
23. How high is the probability that another tsunami like the one on December 26, 2004 will occur in the Indian Ocean?
24. Can Germany also be hit by such a tsunami?

1. How does the tsunami early warning system work in Indonesia?

In most cases, a tsunami is triggered by an earthquake below the ocean floor, and less often by landslides on the ocean floor. The functionality of the German-Indonesian early warning system is based on early registration by earthquake measuring devices in the event of a strong earthquake. The seismological stations will be installed throughout the region and supplemented by stations from Indonesian partner institutes and other countries. As soon as the first information about the location and strength of an earthquake is available, the other measuring instruments, such as GPS stations and coastal levels, are "queried" as to whether they have already registered signals about a possible tsunami.

The data converge in the warning center in the Indonesian capital Jakarta and are evaluated there partly automatically and partly by experienced specialists. With the help of modeling and simulations, the first arrival times and the expected heights of the waves hitting land are calculated. The national tsunami early warning center in Jakarta distributes the warning messages to clearly defined and authorized bodies in the provinces and municipalities, which then implement local warning measures and, if necessary, initiate evacuation or rescue measures.

2. How does this early warning system differ from what is already in use in the Pacific and why has it not been used?

Compared to the Pacific tsunami warning system, which is operated from Hawaii, there is one big difference to the Indonesian early warning system: the wave travel times. A geological fault zone extends southwest of Indonesia. This is where earthquakes occur very often, which in turn - just like severe landslides - can trigger a tsunami. Due to the relatively short distance, such a tsunami can reach the first coastal areas after just 20 to 30 minutes. In Hawaii we find fundamentally different conditions. Here, a tsunami is often triggered by earthquakes at greater distances in the regions around Japan, Alaska or Chile. It often takes several hours for tsunami waves to reach the affected coastlines. Thus, the warning times are significantly longer than off the Indonesian coast.

Conditions comparable to those in Indonesia exist for Japan, where an early warning system has been in operation for some time. In contrast to these two systems existing in the Pacific, the German system has integrated further instrumentation in addition to the "classic" seismology instruments for earthquake localization and the oceanographic methods by means of buoy and level measurements. Here, for example, the technology of the Global Positioning System (GPS) is also used to measure the displacement of the earth's mass. In the future, new types of satellite methods are to be used that enable global sea level measurements and thus the detection of larger waves.

3. Why was no early warning system deployed in the Indian Ocean before December 26, 2004?

The earthquake of December 26th, 2004 and the subsequent tsunami are undoubtedly "events of the century". With a magnitude of 9.3 (Mw), this earthquake, known as the Sumatra-Andaman earthquake, is one of the world's most severe earthquakes that have ever been recorded by an instrument. There were no signals or signs that such a strong earthquake and, above all, a tsunami of comparable destructive power was to be expected. The fact that no comparable event has taken place for many generations has also led to the population in the affected regions underestimating such a risk.

4. How much does it cost to set up the system alone?

The development and implementation of the Indonesian tsunami early warning system cost 55 million euros, which the German government is investing in the reconstruction of the regions in the Indian Ocean affected by the tsunami of December 26, 2004. The work includes the development and installation of measuring instruments as well as the creation of the actual national warning center. The training of scientists to look after the warning center, the training of technicians to maintain the systems and training of the population on how to behave in an emergency also play an important role. The promotion of the local population's awareness of the natural hazard "tsunami" plays an important role.

5. How will the system be financially supported in the long term?

The early warning system was completely taken over by Indonesia on March 29, 2011 and has been operated there by the national Indonesian Service for Earthquakes, Meteorology and Climatology (BMKG) on its own responsibility. The BMKG is a state authority.

6. How is the permanent system functionality guaranteed?

The actual operation of the warning system is now the responsibility of the Indonesians. As part of the GITEWS (German-Indonesian tsunami early warning system) project, they were intensively prepared for operation. The German side will also support them in operation until probably March 2014 as part of the PROTECTS follow-up project through further training measures. When servicing components of the warning system, the responsible authority actively involves external service providers. These were integrated into the training and education measures in advance. This ensures that the expertise is retained and can be passed on.

7. What happens if some sensors fail?

The system uses many different sensors. If individual sensors fail, the system as a whole will continue to run. With seismology (detection of the earthquake) and also with the GPS land stations, it is not relevant to have all sensor stations available, as these are networks. If a level fails, data from the seismometers and GPS networks still remain, so that sensor redundancies are guaranteed.

8. What other fail-safe safeguards are there?

The hardware in the warning center is designed redundantly, i.e. there is a second parallel computer system. The data transmission from the sensor in the area to the warning center also has a second communication option. One speaks here of a so-called back-up communication.

9. How is the early warning system prevented from detecting a simple tidal wave as a tsunami?

In principle, every major wave that is measured near the coast represents a potential danger for the coast. But not every high wave is a tsunami wave. 90 percent of a tsunami is triggered by earthquakes, less often by volcanic eruptions and / or landslides. Corresponding sensors record the event and forward the information to the warning center, where it is compared with other sensor data. If tsunamogenic parameters are recorded there, a warning dossier is immediately issued for the endangered coastline.

10. How are the sensors protected against vandalism?

Land stations are often located on fenced-in private or institute premises. In the case of the buoys, however, there have repeatedly been cases of damage from fishing boats that tie up to the buoys. Cases of willful destruction have NOT occurred so far, despite concerns that have been expressed many times. In order to prevent this in general, however, the United Nations (UN) has an education program in which the population is informed about the importance and use of the respective sensor station, especially in remote rural regions, in order to avoid vandalism and theft.

11. The early warning system registers a tsunami threatening the coast. What is the procedure in such a situation to warn or possibly evacuate the coastal population?

The warning message is generated in the warning center in Jakarta. From here, alerts will be sent to the government and local authorities in the areas likely to be affected. That is why the warning center is manned by the relevant technical experts around the clock, 7 days a week. Due to the fact that the first coastal areas can be hit by the wave after just 20-30 minutes, many actions have to take place in parallel. Defining and implementing these processes and chains of action is one of the most difficult parts of building an early warning system. The prerequisite for the short early warning times is that the population is well trained and knows immediately how to behave in the event of a warning. This can only be ensured through continuous information, regular training and evacuation exercises. A role model here is Japan, where exactly these behaviors are trained in the cities and settlements on the coasts twice a year.

12. You cannot evacuate a city within 20 minutes. Doesn't that mean the system is actually useless?

No. Disaster quakes are inevitable and also not foreseeable. They will always be victims, also claim many lives. But with the tsunami early warning system it will be possible to significantly reduce the number of victims. The system not only benefits the regions that can be hit by a tsunami wave within a very short time, but also the more distant areas, regions, countries. And the faster a warning can be issued, the more time there is to be able to take appropriate precautions (e.g. evacuations). A decisive and important aspect of an early warning system is not just the construction of technical installations and the mere warning of an approaching tsunami. Due to the intensive preoccupation with the warning process in the coastal regions, many preventive measures have been initiated, which in turn significantly reduce the number of possible victims. This includes the creation of hazard maps, the definition of escape routes, the consideration of the tsunami hazard in urban and landscape planning, or the establishment of a risk awareness among the population.

13. Which channels are used to pass on warnings of a tsunami to the population?

Disseminating the warnings is the task of the Indonesian Warning Center and the Indonesian government agencies. It takes place mainly via radio, fax, mobile communications, TV, loudspeaker systems on beaches and at mosques and a network of locally installed sirens. In the long term, procedures such as broadcasting via SMS are also to be examined. However, this option is not ideally suited, since in the event of a disaster, network overloads and thus considerable delays in sending SMS can occur. Solutions based on radio transmitters (FM, MW) and with which a special channel (RDS) can be used comparable to traffic radio are safer. Corresponding radio receivers, which can also be activated via the radio transmitter when they are switched off, have already been successfully tested and are also inexpensive.

14. How can false positives be avoided?

In the decision support system (DSS), a program that displays and evaluates the sensor data in the warning center, it can be seen whether further sensor data could provide an improvement to the existing result. This gives the responsible employee more security when issuing a warning.

15. Are there disaster plans that include e.g. escape routes?

As part of the GITEWS project, evacuation plans and catalogs of measures to protect the population are also being drawn up. The knowledge and experience of the Indonesian partners on the local conditions provides the most important input, in addition to the technical integration of the map material etc. into the early warning system.

16. Are children informed at school about how to behave in an emergency?

In addition to conducting training courses and other training programs for the experts who have been running the Indonesian warning center since the system was completed, educating the population about the dangers and risks of a tsunami and informing them about the necessary behavior in the event of such an event is also a major issue. Experienced partners from the areas of "International Cooperation and Development Aid" prepare appropriate information and create teaching materials for education in schools. Exercises on evacuation and how to behave in the event of a disaster are also regularly carried out in schools.

17. How much time is there between the warning and the arrival of the tsunami, so how much time is there to escape?

The aim of the early warning system is to issue an initial warning within 5 minutes after the first signs of a strong earthquake, for example, that could trigger a tsunami. Assuming that the first coastlines can be affected after 20-30 minutes, there are around 15 minutes to react. Regions and neighboring states of Indonesia such as Malaysia, Singapore, Thailand etc. that are further away from the fault zone southwest of Indonesia, however, have a lead time of one hour or more to take suitable measures.

18. Which personnel does the early warning system require?

Even if, due to the short reaction time in the event of a tsunami, many of the processes in the early warning center have to run automatically, the experience and judgment of experts is an important factor in assessing whether a warning of the population is necessary or not. Experts from the fields of seismology, oceanography, GPS and simulation are therefore deployed in the warning center in Jakarta. The so-called "Officer on Duty" is responsible for the decision about the warning and its transmission to the Indonesian government agencies. The staffing of the headquarters takes place in a seven-day shift operation around the clock.

19. How long does it take to train this staff?

The development phase was completed at the end of 2008 and the early warning system was installed in Indonesia. Technicians and scientists were trained right from the start. On the one hand, they were trained in annual training courses that build on each other and, on the other hand, they were trained through research stays of several months at project partners in Germany up to qualification through a three-year doctoral program. When setting up the various sensor systems in Indonesia, German field engineers are regularly accompanied by local technicians, so that a so-called "training on the job" program teaches them how to set up, maintain and repair each station. Indonesian staff are also regularly trained in installing the communication technology and setting up the hardware in the warning center. The training and further education was part of the project until the handover of the warning system in March 2011.

20. How will the population be supplied with medicines, food and drinking water after a disaster if the infrastructure has collapsed?

The aim must be to build up and secure stocks of food and drinking water, medicines and medical care as well as materials for the rescue and accommodation of those affected in "quiet times". Suitable places and transport routes must also be planned. The Indonesian government has a responsibility to act with the support of international organizations such as the International Red Cross.

21. How many countries or research institutes worldwide have worked on the development and / or installation of the early warning system?

Nine institutions on the German side were involved in the GITEWS project to set up the German-Indonesian tsunami early warning system. The project was supported locally by more than ten Indonesian partner organizations.

22. How important is international cooperation to protect against natural disasters and especially tsunami?

This cooperation is very important. It serves the transfer of knowledge, experience and highly developed technology. In addition, natural disasters cross borders. In the event of a flood, for example, the origin can be in the Alpine countries, where masses of snow thaw, but the consequences of increased water levels in neighboring countries can be much more serious. Joint strategies and courses of action must therefore also be developed in order to protect a region. The GITEWS project is actively involved in these developments, which in the area of ​​tsunami is coordinated by UNESCO, a sub-organization of the United Nations. The German early warning system is thus also a contribution to the establishment of an operational early warning system in the region of the entire Indian Ocean. In principle, almost all countries bordering the Indian Ocean as well as Japan, France, China and the USA are involved.

23. How high is the probability that another tsunami like the one on December 26, 2004 will occur in the Indian Ocean?

Due to the danger of strong earthquakes from the fault zone off Indonesia, a repetition of a comparable catastrophe cannot be ruled out. Experts around the world are working on studies that should show roughly where the next big event would be possible. However, predicting this cannot be done with absolute certainty.

24. Can Germany also be hit by such a tsunami?

There is also a risk of a tsunami in Europe, as the events of Lisbon (1755) and in the Mediterranean Sea in the Strait of Messina (1908) show. For this reason, international groups of experts deal with the development of strategies for the best possible preparation, especially in the Mediterranean and Atlantic regions. The GITEWS project is also involved here.

For Germany, on the other hand, the tsunami issue hardly plays a role in this sense. Strong earthquakes triggering a tsunami are highly unlikely here. Model calculations for a tsunami, which could e.g. be generated by the sliding of the Norwegian continental margin, show that the transit times of the waves through the shallow North Sea are so long that hardly any energy arrives at the coast. The effects would presumably be in the order of magnitude of that of storm surges, as they are caused by meteorological events such as the passage of storm lows and have already occurred several times on the German North and Baltic Sea coasts. However, the affected coastlines are well prepared for these cases.

The questions answered inter alia. Dr. Jörn Lauterjung, Helmholtz Center Potsdam German Research Center for Geosciences (GFZ)

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