What is the probability of a tsunami in Etna? – Science

Volcano

The Etna volcano has kept Sicilians in suspense this year. But it also develops activity under water. Because the slope gradually shifts towards the Mediterranean Sea. Is the tsunami coming now?

November 19, 2021, at 10:10 am.

Nail (DPA). Etna has erupted regularly and spectacularly since February on the Italian island of Sicily. But how does the great activity of volcanoes higher than 3,350 meters affect the slope that slides a few centimeters into the Mediterranean every year?

Kiel scientists want to investigate this question in the coming weeks on their “Hazelnut” expedition with the research ship “Meteor.” “We want to better understand the potential for a tsunami from Mount Etna,” says expedition leader Felix Gross. The team of 16 researchers will begin from Emden in Lower Saxony on 21 November.

flank threatened to go to sea

It has long been known that the southeast side of the volcano is in motion and is slowly slipping into the ocean. The most likely cause is gravity, said Gross, a marine geophysicist at the Center for Oceans and Society at the University of Kiel. Because Etna was built on a layer of soil exposed to extreme pressure. “The whole thing just slides down.”

Scientists from the University, Geomar – Helmholtz Center for Ocean Research Kiel and the Etna Observatory in Catania (Italy) detected slope movements with sensors years ago. “The slope slips two to three centimeters a year,” says Geomar geologist Morelia Urlaub. While motion on the water can be observed using satellite data, researchers at sea rely on acoustic sensors.

sensor on the ocean floor

“We were able to prove that the flank moves under water as fast as it does on land,” Urlaub says. Five sensors on the volatile side of the volcano, about 20 kilometers from the coast, at a depth of about 1200 meters, have been measuring their mutual distances using acoustic signals since 2016. These should be read out with the help of modems and maintained during the next trip.

The researchers are particularly interested in the question of how outbreaks affect slippage. “Are we probably seeing even more movement on the ocean floor?” Urlaub says. For expedition leader Gross, it is fortunate that the sensors have been installed during Aetna’s active phase. It gives a special insight into this time.

small tsunami possible

The 34-year-old says it is theoretically possible to demolish small blocks of slopes. It can generate small waves in the Mediterranean Sea. “In this case we are talking about a tsunami two or three meters high. But they are more comparable to a large wind wave and may not even attract attention. ”Should the slope slide accelerate and Thus could be the start of a potentially catastrophic tsunami, “so we’ll probably see it years ago”. There may be an acceleration in the near future or in 1000 years. There is no reason for illegal painting.

Etna, located on the eastern coast of Sicily, has four main craters and hundreds of secondary craters, from which magma is released during eruptions. A particularly large number of small and large eruptions have occurred from the continuously active volcano since mid-February. Mount Etna’s ashes are not only a problem for the people of the region. It also happened that the airport in the city of Catania at the foot of the volcano had to temporarily cease operations because the runway was dirty.

The research team also wants to remove sediment cores from the slope. They should provide information about whether the volcano’s increased seismic activity has caused any major changes. Until now, researchers have assumed that the forces exerted by rising magma on the sides of the volcano play a subordinate role in the observed slide of the slope.

© dpa-infocom, dpa: 211119-99-57995/2

campaignshift