March 24, 2023

Athens News

News in English from Greece

New magma chamber discovered at Columbo volcano near Santorini

A new magma chamber discovered inside the underwater volcano Columbo, off the Greek island of Santorini, is a dormant threat, a study has shown, even though an eruption is not expected anytime soon.

The new magma chamber was announced in a recent paper published in the journal Geochemistry, Geophysics, Geosystems by a team of scientists led by Kajetan Khrapkiewicz of the Department of Geosciences at Imperial College London. It was identified at a depth of 2-4 km below the seabed, thanks to the first studies using seismic waves and new generation tomographic methods. The shape of the chamber resembles a mushroom, thinner at the base and wider at the top.

Scientists believe the camera may be the key to understanding the intense 2006-07 and 2011-12 seismic activity in this part of the Greek volcanic arc. Earthquakes are apparently associated with an increase in the amount of magma rising from great depths to the source. Using the method of studying seismic waves, the researchers discovered a previously unknown magma chamber under the underwater volcano Columbo.

A new study has found that an underwater volcano whose deadly eruption destroyed the picturesque Greek island of Santorini nearly 400 years ago has a growing magma chamber that could spark another massive eruption within the next 150 years.

Approximately 4 miles (7 km) from Santorini, at a depth of 1640 feet (500 meters) below the sea surface, is Columbo volcano. It is one of the most active underwater volcanoes in the world, and according to historical data, its last eruption in 1650 AD claimed the lives of at least 70 people.

A study published October 22, 2022 in the journalGeochemistry, geophysics, geosystems”, showed that a previously undiscovered magma chamber growing under the Columbo volcano could lead to a new eruption, thereby endangering the residents and tourists of Santorini.

Underwater volcanoes are monitored in the same way as their land-based counterparts, but because underwater seismometers are difficult to install, there are fewer of them, which means scientists have less data on underwater volcanoes. In an attempt to solve this problem, the researchers decided to try a different technique for studying Columbo’s internal mechanics. The scientists used a technique called full-wave inversion, which uses artificially generated seismic waves to create a high-resolution image showing how hard or soft underground rock is.

“Full wave inversion is like medical ultrasound,” the statement said. co-author Michele Paulatto, volcanologist at Imperial College London. “She uses sound waves to create an image of the volcano’s underground structure.” Seismic waves propagate through Earth at different speeds, depending on the stiffness of the rock they pass through. For example, a type of seismic wave called a P-wave propagates more slowly if the rock is more like a magma-like liquid than it is in solidified rock. By collecting data on the speed of seismic waves traveling through the earth, researchers can understand where magma forms.

While on board a research vessel sailing near the volcano, the researchers fired from an air gun, which produced seismic vibrations in the earth’s crust. The seismic data showed a significant decrease in velocity under the volcano, indicating the presence of a magma chamber and not just solid rock. Further calculations showed that the magma chamber had grown at a rate of 141 million cubic feet (4 million cubic meters) per year since its eruption in 1650. The team found that the chamber now contains roughly a third of a cubic mile (1.4 cubic kilometers) of magma.

According to the first author of the study Kaetan Khrapkevich, a geophysicist from Imperial College London, the volume of magma could reach about half a cubic mile (2 cubic kilometers) over the next 150 years. This is the approximate amount of magma that Columbus erupted almost 400 years ago.

Sources: geochemistrygeophysics, geosystems, and others

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