Volcanic lava experiment could save lives
Volcanologists at Lancaster University are cooking lava in the lab in a unique set of experiments designed to help understand hazardous volcanic activity.
This pioneering work involves recreating the extremely high temperatures within moving lava and closely observing enigmatic but dramatic changes that are thought to control how lava flows advance.
Crystals grow as flowing lavas cool and lose gas and this crystal growth makes the lava far more viscous (thicker), slowing it down and restricting how far it can advance.
To understand lava thickening, volcanologists have, for decades, studied the crystals in inactive lava flows that have completely cooled and have tried to estimate how quickly they grew.
However, the Lancaster team can actually witness crystals growing in real lava, in real time, which is far more revealing.
The unusual piece of apparatus, a tiny furnace capable of reaching 1500 degrees Celsius, is housed in a laboratory run by Dr Hugh Tuffen and Dr Mike James at Lancaster Environment Centre (LEC).
Tiny hand-polished wafers of lava are placed inside the furnace and then observed through the microscope as gases escape and crystals grow at sizzling temperatures (over 1000 degrees Celsius).
The results yield new information about crystal growth in lavas and will help scientists make better predictions of how far lavas will advance on active volcanoes such as Etna in Italy.
Dr Hugh Tuffen, a former PhD student at Lancaster and now a Royal Society University Research Fellow at LEC, said: “As far as I know we are the only team using this powerful technology for this purpose.
“We take lava, melt it and watch the crystals grow in real time. The lava actually thinks it’s back inside a lava flow and so does what it does in nature. The trick is that we can spy inside the lava and directly observe what is happening.”
“The crystals thicken the lava up and that’s the main reason why lava flows slow down and stop moving. We are planning to carry out experiments on the whole range of lava types found on Earth and hope that, ultimately, our research could help to save lives.”
The Natural Environment Research Council (NERC) funded the £70k machine, a Hotstage Microscope, and ongoing research is also supported by The Royal Society. The machine can reach temperatures of up to 1500 degrees C and so comfortably reach the temperature of the hottest magma.
The new machine is causing significant interest, particularly with students and visiting academics, and collaborative work is underway with experts from the USA, Germany and France.
“It’s a really great bit of kit,” added Dr Tuffen. “Students love it because it’s so easy to use and they are, consequently, doing some exciting things with it.
“One student is looking at lava from the famous 1990s eruption of Mt Unzen in Japan in the 1990s that killed many people and is studying how crystals grew inside it.
“Another student has taken samples from the world’s most recent eruption of sticky, silica-rich rhyolite magma, in Chile, and has frothed them up to make pumice, measuring how quickly the bubbles grew. This has never been done either and has yielded some great results.
“The Hotstage is so versatile and is a key part of teaching for our Masters students studying Volcanology. We also use it for outreach and recruitment – we recently had more than 200 students and parents through the lab. They were able to watch rocks cook and crystals grow and it always generates a lot of excitement.”
Dr Tuffen, who has just had a major piece of research published using results from the Hotstage, said the furnace work would continue for years and would be extended to examine a range of different phenomena.
Lancaster University is the only UK University to offer a Masters degree in Volcanology.
Magma is the molten rock inside a volcano. It originates deeper underground beneath the volcano. As it rises and is erupted to the surface bubbles and crystals grow. If gases can escape from the rising magma then it comes out gently and flows down the mountain, forming a lava flow. If gases are trapped then the magma shoots upwards explosively, forming bubble- filled pumice.
Source: gillian.whitworth at Lancaster University via Agility
Image: Dr Hugh Tuffen