Researchers have found new evidence that the southeast flank of Mount Etna slides into the sea. The gradual shift could lead to the collapse of the entire runway, increasing the risk of a major tsunami.
Mount Etna, the largest and most active volcano in Europe, is located in the eastern part of the island of Sicily. The volcano shows persistent signs of unrest and has been the subject of study for years.
It has been known for some time that the southeast flank of the volcano glides slowly towards the sea, while the other slopes are largely stable. However, the exact process that triggers this descent is still unknown. Since satellite-based measurements below the sea surface are not possible, the researchers used GeoSEA's new geodetic monitoring network on the seafloor and for the first time recorded the horizontal and vertical movement of a submerged volcanic flank.
Data from the system confirmed that Mount Etna was moving, but the movement is probably caused by gravity, not by the increase in magma, as previously assumed. The catastrophic collapse of the entire flank or its large parts would trigger a major tsunami with potentially extreme consequences for the region.
"At Etna, we first deployed a sonic-based underwater geodesy monitoring network, known as marine geodesy, on a volcano," said First-In-Ear. Morelia holiday from Kiel University. "All in all, our results show that the slope is due to gravity and not due to the increase in magma."
For the study, GEOMAR team researchers deployed a total of five acoustic monitoring transponder stations across the fault line in April 2016 and received a signal from each transponder every 90 minutes through July 2017. As the system was sound-based, it took time for it to sound. The journey showed the distance between the transponders, which in turn allowed the researchers to detect changes in the flank.
"We noticed that the distances between transponders on different sides of the disturbance have changed significantly in May 2017. The flank has sunk four centimeters seaward within eight days and has dropped by one centimeter." Vacation.
This movement resembles a very slow earthquake known as the Slow Slip Event. It was the first time that the horizontal movement of such a slow slip event was recorded underwater.
"The entire slope is in motion due to gravity," said Professor Heidrun Kopp, coordinator of the GeoSEA array and co-author of the study. "It is therefore quite possible that it could catastrophically collapse, which could trigger a tsunami in the entire Mediterranean."