Christmas quake off Sumatra could have seismically activated region – and European tsunamis are also possible

It is well known that strong earthquakes can often cause aftershocks for months or even years. Since the turn of the year, however, it has been quiet again off Sumatra. But a major quake could follow in another corner of the Sumatra region. And Europe is by no means safer.

That the earth resp. The so-called “Indonesian fire belt” is one of the most active volcanic regions on earth, from which the Krakatau explosion in 1883 also originated and in which a super volcano also lies dormant, the explosion of which could change the climate worldwide in a manner similar to a nuclear winter. It is also nothing new that every earthquake is accompanied by pre- and aftershocks. A good year after a major quake, these aftershocks are still possible, but so far the earth has remained calm.


Plate tectonics off Sumatra: the red line shows the fault line of the 2004 quake, the star its center

If it rumbles again, however, this could not be just an aftershock, as John McCloskey, Suleyman S. Nalbant and Sandy Steacy of the University of Ulster’s School of Environmental Sciences report: Rather, the earthquake underlying the Christmas tsunami further increased stresses on the Sumatran faults and the Sunda Trench. A new earthquake of magnitude 7.5 on the Richter scale could be the result, scientists report in the latest Nature.

The Sunda Trench separates Indonesia from the Australian continental plate and was the source of the tsunamis of 1833 and 1861. The early warning system, which has been adopted in the meantime, should be set up as soon as possible, according to the British scientists.

Tsunamis can also occur in Europe

Sumatra, Thailand, Sri Lanka, Maldives and Indonesia are far away for us outside of the vacation – one may hope now with a Sudostasien vacation for a then functioning early warning system. In Europe and Germany, on the other hand, there is no tsunami warning system – it is not necessary, after all, there are no seaquakes here, one would think. However, Thomas Wilke and Thorwald Ewe described in Bild der Wissenschaft 3 that this is not necessarily the case.000 people to their deaths, some of whom sought shelter at the harbor from the firestorms triggered by the quake and were then caught by the tsunami.

8000 years ago, off the coast of Norway – possibly triggered by a minor seaquake or the dissolution of methane hydrate (oko-death in the Jurassic Sea) – an area the size of Iceland slid down 2000 meters and unleashed a tidal wave up to 30 meters high. Until recently, a pile-up of storm surges in that period had been amed to be the cause of the traces that can still be found in abundance today. Methane hydrate dissolution is not limited to cold seas; it could also be to blame for a 7.0 magnitude seaquake – in itself too weak for a tsunami – off Papua New Guinea on July 17, 1998. July 1998 off Papua New Guinea generated a giant wave that killed 2100 people.

Tidal wave caused by port and airport expansion

In 1979, excessive building mania on the Côte d’Azur even generated a home-made tsunami: On what was then Europe’s largest construction site, Nice Airport, 190 hectares of land had been heaped up to 300 meters out into the steeply sloping sea to create a second harbor. On 16. In October, in bad weather, this breakwater with about five million cubic meters of material sank into the sea and slid down 2650 meters. This generated a tsunami which, although not in Nice itself, reached a height of up to three meters in the neighboring town of Antibes, 10 kilometers away, and crashed into the city via the port there. It was only thanks to the bad weather that there were only six deaths in Antibes; a total of 11. In 1963, 2600 people died in a tsunami in a reservoir in northern Italy.

Tsunamis are by no means limited to the sea: if a large quantity of rock slides into an inland lake, the consequences are even more severe because of the smaller total volume of water. For example, a mountain above the Norwegian lake Lovatn near Bergen regularly breaks off – most recently in 1905, 1936 and 1950. In each case, more than 500.000 cubic meters of rock in the water, which created a 44-meter-high wave on the shore 10 kilometers away in 1905 and a 70-meter-high wave in 1936, flattening the villages of Bodal and Nesdal, killing 63 and. 72 people and threw an excursion boat 350 meters inland. How high the wave became in 1950 is unknown, as today only tourists stay at this lake in Hutten. Locals avoid it now.

The highest wave: over 500 meters

The highest known tidal wave was measured in Alaska in 1958: When 40 million cubic meters of rock crashed into Lituya Bay from a height of 900 meters as a result of an 8.0 earthquake, the water spilled over 500 meters on the other side. The traces are still visible today.

If – which also does not require an earthquake – rock slides into the sea from Cumbre Vieja mountain on La Palma or Teide on Tenerife, which are in danger of slipping, this can cause far-reaching tsunamis, especially on the east coast of the USA, but also on the coasts of Western Europe. And while there is a better infrastructure than in Southeast Asia, there are no warning systems for such events because they are simply not expected here.

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