A team of scientists, including researchers from TCD, has found that seemingly predictable volcanoes may have the potential to be very explosive.
While conducting research with the aim of better understanding and preparing for any future volcanic eruptions, an international team of volcanologists working on remote islands in the Galápagos archipelago has made a surprising discovery.
The team, led by Dr Michael Stock of Trinity College Dublin (TCD), published findings on two volcanoes that have only ever erupted compositionally uniform basaltic lava flows at the planet’s surface. Writing in Nature Communications, the team said it was able to reconstruct the chemical and physical characteristics of magmas stored underneath volcanoes by deciphering the compositions of microscopic crystals in the lavas.
This showed that despite the monotonous eruptions of these volcanoes, magmas beneath the surface are extremely diverse and have similar compositions to those erupted at Mount St Helens.
‘Secret magmas’ in hiding
“This was really unexpected,” Stock said. “We started the study wanting to know why these volcanoes were so boring and what process caused the erupted lava compositions to remain constant over long timescales. Instead we found that they aren’t boring at all – they just hide these secret magmas under the ground.”
The team believes uniform basaltic lavas erupt when the amount of magma flushing through the ground beneath the edifice is high enough to ‘overprint’ any chemical diversity. This can occur when volcanoes are located close to a ‘hot spot’ – a plume of hot magma rising towards the surface from deep within the Earth.
The discovery of chemically diverse magmas suggests that much more explosive eruptions could come from seemingly predictable volcanoes.
“Although there’s no sign that these Galápagos volcanoes will undergo a transition in eruption style any time soon, our results show why other volcanoes might have changed their eruptive behaviour in the past,” Stock said.
“The study will also help us to better understand the risks posed by volcanoes in other parts of the world – just because they’ve always erupted a particular way in the past doesn’t mean you can rely on them to continue doing the same thing indefinitely into the future.”