AN UNDERWATER volcano off the coast of the Canarian island of El Hierro is still belching out water of 39ºC nearly five years after its eruption, according to a group of Spanish and German scientists.
A small submarine from the Helmholtz Oceanographic Centre in Kiel went 88 metres under water between October 12 and 13 to examine the volcano, the crater of which is 220 metres below the sea.
The Spanish Oceanographic Institute (IEO) and Las Palmas University in Gran Canaria took part in the study, since they intend to monitor the volcano every four years.
When it erupted in 2011, it caused a bubbling of scalding water for several weeks and led to over 8,000 earthquakes on the island – although the most intense, only a small handful, measured around 2 or 3 on the Richter scale; enough to be felt by the population, but not enough to cause injury or damage.
Underwater robots – the latest of which to go down was the Liropus 2000 in 2014 – have been taking samples from the 100-square-metre crater, and the JAGO submarine has allowed researchers to observe its hydrothermal activity close up.
“Our results have shown that the degasification phase of the volcano has turned the area into a natural laboratory, a scaled-down ecosystem, allowing us to study the effects of global warming on the marine environment,” reveals oceanographer, professor Magdalena Santana Casiano.
The Liropus 2000 collected what appeared to be iron oxide deposits back in 2014, as well as bacterial 'blankets' and emissions of low-temperature fluid near the main crater.
A year later, clouds of gas and acidic water were detected in the south-east area of the crater – and now, the most active part appears to be in a depression along one side of the peak.
Fresh volcanic crystals have been collected by the JAGO, showing this depression is likely to be the youngest part of the volcano.
Professor Santana Casiano, who went down in the JAGO with IEO researcher Eugenio Fraile, saw that the surface of this secondary crater was coated with very new ash and scaly deposits of iron oxide.
It is letting off water jets of around five centimetres (two inches) in diameter over an area of some 100 square metres, of a heat of 39ºC, at the same time as its magma – below the seabed subsoil – has been cooling down, reveals Mark Hannington, marine geologist from the German Oceanographic Institute.
Several other bodies have been taking part in the ongoing vulcanology research, including the Spanish Seaweed Bank, the University of Santa Cruz in Tenerife, and the city's Natural Sciences Museum.