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Nr. 77, 06.07.2013  voriger  Übersicht  weiter  REIHEN  SUCHE 

Are Oceans dangerous?

Seaquakes and associated tsunamis, sea level rise, floods and storms: these are the threats habitations along the coasts face today. Kiel University’s Cluster of Excellence »Future Ocean« is working on evaluating the impacts on coastal zones.

Tsunamis can be caused by so called submarine landslides and pose a risk to people. Scientists of Kiel University are investigating those threads how to prevent destruction. Foto: Wikimedia

The tsunami of 2004 is still very present in the minds of many people. Even Hollywood has adapted the drama and made a movie out of it – »The Impossible« starring Ewan McGregor and Naomi Watts premiered in Germany in January 2013.

The catastrophe on Christmas Day 2004, in which 230.000 people died, was caused by a sea­quake that triggered a massive tsunami which flooded the coastal lines and swept away every­thing in its path. It is just one example of the dangers that coastlines face today: their inhabitants are not only threatened by a rising sea-level or tsunamis caused by seaquakes. Submarine landslides can also set off massive waves. As these occur close to the shore and are not detected by any observation systems, advance warning is difficult.

»Submarine landslides are a natural danger«, explains Sebastian Krastel, geophysicist at Kiel University and a member of the Cluster of Excellence »Future Ocean«. »Current investigations have shown that up to 20 percent of all tsunamis are caused by submarine landslides.« The landslides are not only a danger to coastal habitations, but also to infrastructures on the sea floor. The masses can destroy cables or oil platforms. Furthermore, the slide may foster the dissociation of gas hydrates, which are only stable at low temperatures and high pressures. The slide causes a pressure release which leads to the melting of the hydrates. This may free huge amounts of methane – a gas that is known to accelerate global warming.

»Future Ocean« has just gone into its second phase of funding, which is divided into various research topics. »The idea of the research topic ›Dangerous Ocean‹ is to examine the entire series of reactions that happen at the depths of the ocean up to the consequences along the coasts«, Krastel states as he explains his interdisciplinary approach. Several research groups are involved in the »Dangerous Ocean«. Krastel is part of a research team that also includes Jan Behrmann of the GEOMAR Helmholtz Centre for Ocean Research Kiel, Karl Stattegger, head of the Sedimentology, Coastal and Continental Shelf Research group at Kiel University (Institute of Geosciences), and Athanasios Vafeidis, leader of the group Coastal Risks and Sea-Level Rise at Kiel University (Institute of Geography).

While Krastel is exploring the depths of the ocean along the continental slope, Stattegger’s research area is at the continental shelf and near land. He is reconstructing the various levels of the ocean. »We are examining the changes along the coast and its foreland«, Stattegger describes his part in the research topic.

»Based on these results we conduct a risk assessment
of which coasts are at risk.«

In countries where safety measures are possible, Stattegger and his team also advise local governments whether or not to become active and »intervene constructively«.

To educate experts and legislative bodies alike is one aim of the Cluster of Excellence. »It is important to understand the impacts that certain processes and events like sea-level rise, floods and storms have on people and eco-systems«, Vafeidis explains, »because in order to manage coastal areas well, you need to understand the full extent of those impacts.« Vafeidis has contributed to an EU-paper on the expected impact of sea-level rise in Europe within this century. His research topic focuses on the land segments of coasts. His findings, in combination with contributions from colleagues, will ultimately be reflected in global adaptation programs. The results are also used in climate negotiations for providing financial support to developing countries which are suffering from the climate change and cannot bear the costs of adaptation by themselves. While the oceans might pose a danger to coasts, researchers at Kiel University are working hard on eliminating unforeseen impacts, and shedding light on these extensive processes.

Ann-Christin Wimber
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