This is a Mediterranean volcano that can erupt violently in 150 years.

About four hundred years ago, in AD 1650, Columbo broke through the surface of the sea and exploded, killing 70 people on Santorini. Thera (Santorini) BC This event, not to be confused with the devastating volcanic eruption that occurred around 1600 C., was caused by magma deposits growing beneath the surface of Columbo. Now the researchers say the molten rock in the chamber has reached a similar volume.

Research published in the journal Geochemistry, Geophysics, Geosystemshas been first person to use full-waveform inverse seismic imaging to look for changes in subsurface magmatic activity One of the submarine volcanoes along the Hellenic Arc where Columbo is located.

Full waveform inversion technology is used to study seismic profiles (ground motions over kilometers) and to evaluate differences in wave velocities that could indicate underground anomalies. The study showed that this technology could be used to locate potential locations of moving magma masses in volcanic regions and to determine their size and melting rates.

The seismic profiles were obtained after researchers fired air cannons from a research vessel sailing over the volcanic region.It causes seismic waves recorded by ocean floor seismometers located along the arc.

“Full waveform inversion is similar to a medical ultrasound,” said M. Paulatto, a volcanologist at Imperial College London and the study’s second author. “It uses sound waves to create an image of a volcano’s subterranean structure.”

According to the study, a significantly lower velocity of seismic waves moving below the seafloor indicates the presence of a moving magma chamber below Columbo.

According to Kajetan Chrapkiewicz, a geophysicist at Imperial College London and lead author of the study, available data on submarine volcanoes in the area were sparse and uncertain, but the intense diversity of seismic profiles and the use of full waveform inversion allowed them. to get much sharper images than before. The large magma chamber now described has been growing at an average of about 4 million cubic meters per year since Columbo’s last eruption in 1650 AD.

A large explosive eruption in 150 years

According to the study, the total volume of melt deposited in the lower Columbo magma reservoir is 1.4 cubic kilometers. According to Crapkiewicz, If the current rate of growth of the magma chamber continues at some point in the next 150 years, Columbo could reach two cubic kilometers of molten material ejected during the 1650 MS eruption. While the volumes of the volcanic melt can be estimated, there is no way to know for sure when Columbo will erupt next.

Features of the magmatic system discovered at Columbo heralded a highly explosive eruption similar (but smaller in size) to the last Hunga Tonga-Hunga Ha’apai eruption, according to the study authors. Although the danger did not seem imminent, an eruption occurred at the Columbo volcano. It could be more catastrophic than the Tongan explosion because of its proximity to Santorini’s population centre.Greece is located only 7 kilometers from the volcano.

Columbo is located in a relatively shallow part of the Mediterranean at a depth of about 500 meters and is likely to increase its explosiveness, according to current estimates. Researchers predict that a tsunami and an eruption column containing large amounts of ash tens of kilometers high will form. When Columbo exploded.

Jens Karstens, geophysicist at the GEOMAR Helmholtz Center for Ocean Studies in Kiel, underlined the importance of the latest findings. “With studies like this, more can be learned about how volcanic structures work, what to expect from them and where to expect an eruption, and this information can be used to design underwater volcano monitoring systems.”

The study adds to the growing knowledge base about Columbo, the most active underwater volcano in the Mediterranean, and the dangers it poses. According to the researchers, full waveform inversion technology could be used to identify similar reservoirs of magma hiding beneath other active submarine volcanoes. However, it can be a spatially restrictive and slow process that will be optimized along with other techniques such as volcanic sediment drilling and seismographic monitoring to help form a better idea of ​​what’s really going on beneath submarine volcanoes.

underwater observatory

Over the past few years, an international team of scientists has Santorini’s seabed volcanic observatory, SANTORY, is equipped with scientific instruments that can measure the progress of Columbo’s volcanic activity.. SANTORY is still in development, but according to Chrapkiewicz this is a good example of what an underwater volcanic monitoring station could potentially look like.

As Paulatto points out, there are more terrestrial monitoring stations for continental volcanoes than for submarine volcanoes. Monitoring volcanic activity below the ocean’s surface is more complex and expensive than on land. But that doesn’t make it any less necessary, Paulatto said.

Together with data collected by SANTORY and the International Ocean Exploration Program’s Expedition 398 sediment drilling expedition, the researchers hope this study will help convince policymakers of the critical importance of monitoring stations in real-time at submarine volcanoes.

“We need better data on what’s really going on underneath these volcanoes.” Crapkiewicz explained. “Continuous monitoring systems allow us to better predict when an explosion may occur. With these systems, we can probably have information a few days before an explosion happens and people can evacuate and stay safe.”

Reference work: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022GC010475

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