Tsunamis are a natural hazard that have not received as much attention in Europe as many others. Professor Behrens explains the current research landscape and why preparedness for tsunami risks is important in Europe as well.
An applied mathematician, Professor Behrens has over 30 years of experience in the field of numerical methods for atmospheric and oceanic simulation. He explains to us the phenomenon of “tsunami”, related ongoing funding and research initiatives and how the Knowledge Network can help in this area.
Professor Behrens, tsunami risk is maybe less well known in Europe. It is often associated with the disaster that occurred in December 2004 in the Indian Ocean. Would you say that this natural hazard is relevant for the EU, as well? Could something similar occur on European coastlines?
Indeed, I often see astonished faces when I say that the Mediterranean is the ocean region with the second largest occurrence of tsunamis after the Pacific!
While the Pacific “Ring of Fire” (a tectonic fault line surrounding the Pacific) causes the largest tsunami-genic earthquakes, the situation in the Mediterranean is more complex. The Aegean has frequent earthquakes, with mostly small to mid-sized tsunami events. The most recent ones happened just a few years ago, 2017 and 2020.
But volcanic eruptions and underwater landslides also cause tsunamis in these waters. There’s a major event about every 100 years. The last one in the Straight of Messina in 1908 caused approx. 60,000 casualties, 2,000 caused by the tsunami alone.
But it isn’t only the Mediterranean. Norway has encountered several deadly tsunamis caused by collapsing mountain flanks, leading to huge inundation in the narrow fjords. And probably the most infamous is the 1755 tsunami that devastated the city of Lisbon, the source of which is still under scientific investigation.
You have participated in a number of research projects around tsunami risk, can you tell us about them?
I lead the COST Action Accelerating Global science In Tsunami HAzard and Risk analysis (AGITHAR), which is about to finish an open access ‘Cookbook’ for probabilistic tsunami hazard and risk assessment.
We hope to sustain the community effort by developing a business model for an association providing guidance and services in hazard and risk analysis for local communities and industry stakeholders as well as inter-governmental bodies. In fact, the COST Association that initially funded AGITHAR has awarded us a so-called COST Innovators Grant, to help us in this effort.
This project is financed as part of COST, the “European Cooperation in Science and Technology” (COST). What type of funding mechanism is that?
COST celebrated its 50th anniversary in 2021. It is an intergovernmental cooperation supporting scientific collaboration by funding meetings, research stays, expert exchange, training and scientific transfer. It has been financed by national funds and EU funding under various Research and Innovation Framework Programs such as Horizon 2020 and Horizon Europe.
COST Actions' gather experts from diverse disciplines around a specific topic in need of increased collaboration for solving urgent problems. AGITHAR for example consolidates methods in probabilistic tsunami hazard and risk analysis. Probabilistic methods have gained attention recently because they allow better quantitative assessment under large uncertainties. As you can imagine, it is hard to foresee where, when and with what magnitude earthquakes or landslides will happen. Probabilistic approaches allow us to prepare, with reasonable assumptions about recurrence rates and possible risks.
What are the challenges in modelling and managing the impact of tsunamis?
There are many challenges. On the scientific side, the available data is still scarce. Even though tsunami events are rigorously surveyed with standardized procedures since the late 1990s, data on true water flow behaviour, the forces on buildings, or the effects of certain evacuation and disaster management decisions are very hard to obtain. So even though the models themselves are pretty solid by now, the results still incorporate quite a bit of uncertainty.
When we look at communities, the disaster situation with respect to tsunamis is very complex. These disasters are very rare but can cause extreme disruption. At the same time, warning times are very short – only minutes. So, preparedness measures need to be well coordinated with an integrated monitoring and warning system, which involves many different actors and complicated information workflows.
Are there any additional initiatives?
There are several, but I would like to highlight two, which I am personally involved in. In the context of the Digital Earth initiative of the ERC, I am participating in developing a tsunami digital twin component to be incorporated into the digital twin for geohazards (DT-GEO). And data and modelling capacities are made available to the scientific community through the European Plate Observing System (EPOS).
Do you see any gaps in research up to now?
In the COST Action AGITHAR, we assessed the research gaps together with about 50 experts from the community. The results have been published and serve us as a whitepaper for future research initiatives.
Among the most pressing research gaps are data for landslide-induced tsunamis. Other gaps concern vulnerability data, in particular what factors are important to reduce tsunami impact on exposed coastal communities. These gaps were rated as hard to tackle, as well as highly sensitive with respect to the hazard and risk assessment outcomes.
In a second report we also evaluated gaps in the social context. The question was: “what are the current gaps in risk communication and management, and where can we find good practices?” Tsunami risk perception in Europe is generally low and a number of research and action paths out of this dilemma are sketched.
Do you have recommendations for coastal states in terms of preparedness? Is tsunami risk reflected in national risk assessments?
In most European countries, tsunami risk is still an open field of development. While five tsunami warning centers have been accredited in the context of UNESCO’s Intergovernmental Coordination Group for the Tsunami Early Warning and Mitigation System in the North-eastern Atlantic, an holistic integration into national and local warning and disaster management procedures is still not complete in the Mediterranean and connected seas (ICG/NEAMTWS). There are several good examples however; Italy and Greece have made good progress and France is also well advanced. Even Germany - not considered greatly exposed to large tsunamis - has integrated tsunami warning into storm surge warning routines. This is useful because stakeholders can then train and refine disaster management procedures on a regular basis.
But a lot still must be done. In particular, fast evacuation plans, vertical evacuation procedures, planning for safe areas, redundant infrastructures, etc. are long-term efforts. And due to the scarcity of tsunami events, expertise is often limited. This makes the information exchange in an international context very important and fruitful.
What could the Union Civil Protection Knowledge Network do to help connect researchers and practitioners?
Awareness is always useful. The fact that most people, including disaster managers, are not aware of the tsunami risk in Europe causes delays. So informing practitioners about some of the current events and potential future risks may help to raise awareness.
The scientific community often lacks understanding for the needs of those working on ‘ground zero’. A very important factor is communication about uncertainty and on how to deal with it. A common understanding and mutual trust in the experience of each community is mandatory.
When I was helping to set up an end-to-end tsunami early warning system in Indonesia – the InaTEWS system - I had very good experience with trans-disciplinary round table discussions, involving stakeholders from local decision makers, disaster management such as Red Cross, Fire Brigade, or Military, and scientists from diverse disciplines – physical sciences as well as social sciences.
Open, goal-oriented, and knowledgeable communication remains paramount in preparing for such disasters.
An applied mathematician with a PhD from Bremen University and Habilitation at Technische Universität München, Munich, Jörn has worked for 30 years in the field of numerical methods for atmospheric and oceanic simulation. He developed adaptive mesh refinement methods for atmospheric multi-scale phenomena. His fields of expertise are numerical geophysical fluid dynamics, high performance computing, and numerical solution of partial differential equations. He became head of the tsunami modeling group at Alfred Wegener Institute (AWI) in 2006. With his group, he developed the simulation component of the German-Indonesian Tsunami Early Warning System (GITEWS), in operation since November 2008. Since 2009 Jörn is a professor for numerical methods in geosciences at Universität Hamburg, Germany. He was a principal investigator in various multi-year tsunami research projects and currently leads the COST Action AGITHAR.
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