The oceanographic vessel has returned to the port of Catania with an international team of researchers on board who has collected important data to better understand the causes and extent of Etna's underwater movements
After 13 days of navigation off the coast of Catania, the expedition ended Meteor M198 organized by GEOMAR Oceanographic Research Center in Kiel (Germany).
On the scientific cruise, the main purpose of which was to investigate the submerged portions of the south-eastern flank of Etna constantly moving under the waters of the Mediterranean, theNational Institute of Geophysics and Volcanology (INGV).
“INGV has been monitoring the slow but progressive movements of Etna for several years”, explains Alexander Bonforte, INGV researcher who was on board the M198 expedition. “These small movements, which do not only involve the emerged part of the volcano, are not normally particularly dangerous, however in some cases and in particular conditions they can become more substantial and give rise, in addition to the well-known earthquakes which periodically affect the eastern flank, also, for example, underwater landslides".
The expedition involved an international research team trying to understand whether the south-eastern flank of the volcano is sliding towards the Ionian as a single block or in several portions and what the origins of this dynamic are.
“The most ambitious objective of our expedition was to highlight how underwater observations and measurements are fundamental to better understand structures such as Etna and complex phenomena such as sliding of the side of a volcano into the sea, be it coastal like Etna or island. In this context, combining the datasets coming from the sea with those processed on land through structural, GNSS and satellite surveys allows us to have a real 360° observatory on the volcano.", goes on Bonforte.
To obtain the necessary data, researchers on board the Meteor vessel took a multidisciplinary approach. In addition to the collection of rock and sediment samples and mapping of the seabed carried out thanks to multibeam sonar and to sophisticated people underwater drones, geodetic techniques have made it possible to exploit a network of acoustic sensors already installed on the seabed off the coast of Catania in 2016 to calculate, based on the propagation times of the sound waves, the relative sliding movements between the various points of the network.
These measurements have already made it possible to detect the active deformation on the continuation of the well-known Acitrezza fault, at least up to 1200 meters deep.
Furthermore, the mission was an opportunity to experiment with a technique never before applied to volcanoes which involved the installation of two piezometers to measure the variations in pressure and temperature of the water contained in the first 5 meters of sediment on the seabed near the fault.
The objective, in this case, is to try to understand whether, as already highlighted in the case of some earthquakes, a movement of the volcano's flank is accompanied or can be anticipated by changes in the characteristics of the fluids present inside it.
“The paradigm we are adopting is to 'remove the water', at least as a mental limit. The coastline that delimits all the maps is not in fact a geological or geodynamic limit, but only a limit to our observation capabilities. Etna is among the best studied volcanoes in the world, an open-air laboratory, and this has allowed an enormous advancement in knowledge of the geological phenomena that characterize it; this makes the knowledge gap on the mountainside that continues below sea level even more evident”, he adds Alexander Bonforte.
“Each oceanographic campaign adds a piece to the enormous spectrum of observations that can and must be conducted on the seabed in front of the volcano and poses new questions that we will try to answer with subsequent campaigns. It is the essence of our work as researchers and of the progress of knowledge, a stimulating journey full of questions to be answered"he concludes Bonforte.
Useful links:
National Institute of Geophysics and Volcanology (INGV)
After 13 days of navigation off the coast of Catania, the expedition ended Meteor M198 organized by GEOMAR Oceanographic Research Center in Kiel (Germany).
On the scientific cruise, the main purpose of which was to investigate the submerged portions of the south-eastern flank of Etna constantly moving under the waters of the Mediterranean, theNational Institute of Geophysics and Volcanology (INGV).
“INGV has been monitoring the slow but progressive movements of Etna for several years”, explains Alexander Bonforte, INGV researcher who was on board the M198 expedition. “These small movements, which do not only involve the emerged part of the volcano, are not normally particularly dangerous, however in some cases and in particular conditions they can become more substantial and give rise, in addition to the well-known earthquakes which periodically affect the eastern flank, also, for example, underwater landslides".
The expedition involved an international research team trying to understand whether the south-eastern flank of the volcano is sliding towards the Ionian as a single block or in several portions and what the origins of this dynamic are.
“The most ambitious objective of our expedition was to highlight how underwater observations and measurements are fundamental to better understand structures such as Etna and complex phenomena such as sliding of the side of a volcano into the sea, be it coastal like Etna or island. In this context, combining the datasets coming from the sea with those processed on land through structural, GNSS and satellite surveys allows us to have a real 360° observatory on the volcano.", goes on Bonforte.
To obtain the necessary data, researchers on board the Meteor vessel took a multidisciplinary approach. In addition to the collection of rock and sediment samples and mapping of the seabed carried out thanks to multibeam sonar and to sophisticated people underwater drones, geodetic techniques have made it possible to exploit a network of acoustic sensors already installed on the seabed off the coast of Catania in 2016 to calculate, based on the propagation times of the sound waves, the relative sliding movements between the various points of the network.
These measurements have already made it possible to detect the active deformation on the continuation of the well-known Acitrezza fault, at least up to 1200 meters deep.
Furthermore, the mission was an opportunity to experiment with a technique never before applied to volcanoes which involved the installation of two piezometers to measure the variations in pressure and temperature of the water contained in the first 5 meters of sediment on the seabed near the fault.
The objective, in this case, is to try to understand whether, as already highlighted in the case of some earthquakes, a movement of the volcano's flank is accompanied or can be anticipated by changes in the characteristics of the fluids present inside it.
“The paradigm we are adopting is to 'remove the water', at least as a mental limit. The coastline that delimits all the maps is not in fact a geological or geodynamic limit, but only a limit to our observation capabilities. Etna is among the best studied volcanoes in the world, an open-air laboratory, and this has allowed an enormous advancement in knowledge of the geological phenomena that characterize it; this makes the knowledge gap on the mountainside that continues below sea level even more evident”, he adds Alexander Bonforte.
“Each oceanographic campaign adds a piece to the enormous spectrum of observations that can and must be conducted on the seabed in front of the volcano and poses new questions that we will try to answer with subsequent campaigns. It is the essence of our work as researchers and of the progress of knowledge, a stimulating journey full of questions to be answered"he concludes Bonforte.
Useful links:
National Institute of Geophysics and Volcanology (INGV)
