by Alessandra Cardone
ROME, Jan. 22 (Xinhua) -- After the massive eruption near the island of Tonga last week, Italian media for days run headlines and in-depth articles, and talk shows focused on one same topic: volcanoes.
They meant to report about the real dimension and aftermath of the submarine volcano's eruption that hit the south Pacific island on Jan. 14. They also wanted to address Italian audience's fresh curiosity about the domestic situation.
Would a similar eruption be possible in Italy? Which -- among the many domestic volcanoes -- was the most dangerous in the immediate? What was surveillance system?
Experts were called in to provide an accurate picture. Journalists and people became aware of an interesting, although disregarded, detail: there were submarine volcanoes in their own backyard too.
QUIESCENT GIANTS
"Indeed, there are several submarine volcanoes of various shapes and sizes in the Tyrrhenian Sea and in the Strait of Sicily," Guido Ventura, volcanologist with Italy's National Institute of Geophysics and Volcanology (INGV), told Xinhua in an interview.
Some of them showed a very low-energy seismic activity and emission of hot fluids, so they could be called "active but in a state of quiescence."
"The two largest ones are the Marsili -- which is 60 to 70 km long and 25 to 30 km wide -- and the Palinuro; both are peculiar because they are volcanic complexes characterized by linear structures," he said.
Ventura has been senior INGV researcher since 2003. His researches have brought him to collaborate, among other institutions, with the Chinese Academy of Sciences, the Jilin University in Changchun, and the Jilin Earthquake Agency of the China Earthquake Administration.
The scholar confirmed the priority in Italy is assigned to other volcanoes (all of which above the waters), in terms of prevention, monitoring, and emergency plans.
In some areas of Italy, people are used to live and thrive under the shadow of an active volcano. This is the case of Catania in eastern Sicily, where the Etna -- one of the most active volcanoes in the world -- is affectionately nicknamed by residents as "the mountain."
There is Stromboli, the most northeast among the Aeolian Islands, famous for its persistent mild to moderate activity, which provides explosive (or "Strombolian") spectacular eruptions.
There are the Vesuvio and the Campi Flegrei in southern Campania region, both located in densely populated areas. The red zone outlined by the emergency plan for them comprises 25 municipalities across the Naples and Salerno provinces.
LOW RISK
Nonetheless, the public and scientific interest around submarine volcanoes is growing, according to the volcanologist. Would they pose a concrete risk in terms of eruption and a consequent possible tsunami? Should people be specifically concerned in Italy?
"A risk linked to possible eruptions exists, although we have discovered through recent studies that the Marsili's last eruption dates back some 3,000 years," Ventura replied.
He noted that while the Marsili's apical part is at 500 meters of depth, that of the Palinuro is only 80 meters under water, which means a latter's possible eruption would pose a greater risk for the Italian coasts.
"Overall, the entire central Mediterranean has a tsunami risk factor, not only for the presence of submerged volcanoes, but due to possible earthquakes and underwater massive landslides," he added, recalling that the INGV plays the role of Tsunami Service Provider for the whole Mediterranean.
"We are currently running simulations of tsunamis from submarine landslides ... And, for the Marsili and the Palinuro, the results we have already published indicate a minimal risk."
Yet, Ventura and other top Italian scientists highlighted that submarine volcanoes are not currently monitored 24/7, nor in the Mediterranean.
"There are two reasons for that, the first of which is that continued monitoring has very high costs -- a day of oceanographic ship costs around 20 thousand euros (some 22,000 U.S. dollars), just to have an idea," he explained.
The second reason is the above-mentioned priority set by Italy's Civil Protection Agency on the other volcanoes.
"The Italian situation therefore is normal, we could say ... yet, our hope is to be able to carry out as many oceanographic campaigns as possible, in order to collect data over the time that would allow us to observe possible changes," he stressed. ■