In 2020, Dr. Emma Nicholson, a volcanologist and associate professor in the Earth Sciences department at University College London, joined a team of scientists on an expedition to the South Sandwich Islands to study the chemistry of volcanic gasses released in the volcanic arc. Harsh weather conditions prevented the summiting of Mount Michael, an active volcano on Saunders Island, which may be the home of a rare volcanic phenomenon. Earlier this year, Nicholson led another expedition to finally summit Mount Michael in search of the world’s eighth lava lake. Her journey is the subject of a National Geographic documentary that premiers today.
Dr. Nicholson set aside some time to discuss the film and her research with SCINQ.
You have gone to great and dangerous lengths to scale Mount Michael and peer into its caldera. Why is it so important to you and what is its significance?
Scientifically, there is so much to learn from this volcano, and the South Sandwich arc more generally. It is a really interesting setting, because these volcanoes are so young (only 10 million years old!) and so represent some early immature versions of the more developed volcanic systems that we see in places like the Andes. Lava lakes are also incredible natural laboratories to observe volcanic processes right in front of us – it is as though we have “taken the lid off” to peer inside at processes normally taking place deep out of sight. The opportunity to study them is so important to improving our ability to relate the monitoring measurements we take (gas chemistry, earthquakes, heat emissions, ground deformation etc) to actual observations of volcanic activity. Studying this volcano has also become a bit of a personal journey too, as we attempted this ascent once before and were forced to turn back by the ferocious weather, so I had unfinished business here. I am also rather tenacious, and being told that something is impossible simply makes me more determined!
What is a stable lava lake and why is it such a rarity? Why don’t the vents seal up and turn into rock?
A lava lake is essentially where magma remains molten/liquid within a volcanic crater at the Earth’s surface for long periods of time (sometimes years to decades!). Usually, magma that rises to the surface will cool and crystallise, solidifying quickly, but at lava lakes the surface magma is replenished and kept hot by the continual supply of fresh rising magma and hot gases (the cooler magma then sinks down, forming a cycle). They are rare as it requires a careful balance of conditions: sufficient pressure in the magma reservoir to supply enough rising magma and gas to keep the lake liquid, but not too much to trigger an eruption. There are only a handful of long-lived lava lakes known around the world; and they can drain and disappear very suddenly (e.g. Kilauea, Hawaii, in 2018).
Prior to your visit, what was known about Mount Michael?
Mt Michael has mostly been studied by satellites in space, with less than a handful of in situ observations. Early reports from sailing vessels always comments on the constant gas plume, being emitted from the summit crater. Even satellite data is scarce, due to the frequent cloud cover that envelopes the southern ocean. What we did know, is that a thermal “hotspot” with temperatures far exceeding the surroundings has persisted inside the crater for decades. Recently, a paper analysed these thermal signals using new techniques and found temperatures consistent with molten lava (> 1000 degrees C). All the evidence pointed to a long-lived lava lake, that was releasing large amounts of volcanic gases every day and was capable of more explosive eruptions in its history. We had to go look closer, and collect valuable ground-based observations that provide anchor points for satellite-based data sets.
Can you discuss some of the field experiments you were able to perform under such challenging conditions? What have the some of the samples yielded?
We had several science goals beyond simply confirming the existence of this lake and ground-truthing satellite observations. Lava lakes are one of the most important natural “laboratories” for studying and learning about volcanic processes because we can see them happening right in front of us instead of being hidden out of sight deep underground. They are very important for learning how to relate the monitoring data we collect (e.g. seismicity/earthquake activity; temperature; surface velocity; volcanic gas chemistry) to actual observations of how the magma is behaving, so that we can deploy these techniques elsewhere at other volcanoes and know how to interpret the signals, particularly in the context of forecasting potential eruptions before they occur. We were also looking to investigate the conditions that permanent monitoring equipment would need to withstand in this polar environment, so that we are better prepared to develop these technologies.
- We collected samples of the volcanic gases being emitted from Mt Michael using a real-time gas sensor called a multigas (for measuring gas chemistry) and a camera that operates in the ultraviolet (for measuring gas emission rates) to place constraints on how deep magma is being stored, what volume of magma is being supplied to the surface, and the amount of gases such as CO2 being supplied to the atmosphere by volcanic activity. The gas chemistry is very sulfur-rich, consistent with magma being present and circulating at very shallow pressures. The SO2 emission rate also requires a magma supply of approximately ~40,000 cubic metres per day.
- We collected thermal imagery of the lake using a drone, to try to visualise the lake and the speed that it is overturning. Observations suggest a lake surface around 15 m in diameter, at present. There is strong evidence that this changes through time as the lake rises and falls.
- We installed a temporary seismometer to measure the earthquake activity during our field expedition. We detected numerous small earthquakes per day from Mt Michael, as well as larger regional earthquakes from along the arc and even from the other side of the planet!
- We collected samples of the snow and glacial water around the island, to determine to influence of volcanic “pollution” on changing the acidity and chemistry of the water (see more detail in answer below)
Saunders Island, part of the South Sandwich Islands, is just about as isolated and hard to reach as it gets. Was this advantageous in terms of collecting samples?
This was hugely valuable for one particular line of research. Volcanoes that host lava lakes are part of a type of volcano called an “open vent volcano”, meaning they release gases to the atmosphere all the time, even when not erupting. These gases pose a huge health hazard to communities living nearby, degrading both air and water quality, often making water undrinkable. Mt Michael was a perfect case study to explore the influence of volcanic gases on water quality as it is so remote we know that any pollution measured in the water samples is volcanic (rather than human) in origin. The water was extremely acidic and contained abundant dissolved trace elements such as lead and copper. Understanding this further will contribute to developing improved solutions to manage this health hazard in more populated volcanic regions, such as around Masaya volcano in Nicaragua.
The volcano actually seemed to be a compliant bystander to the drama unfolding between your expedition and the weather. Was there any point you really thought things wouldn’t work out?
The three days where we were essentially trapped in our tents by a storm raging outside were incredibly frustrating, and we had plenty of time to lie there and worry. The weather forecasts were just looking worse and worse, and there seemed no window of opportunity. We were also becoming very aware that our time ashore was running out, as our tents were breaking under the conditions; we’d already had to collapse two of them. I honestly despaired that the conditions would never cut us the break we needed to make another ascent and collect the observations we needed, before we had to evacuate.
Finally, is there a return to Mount Michael in the plans down the line?
There is still much more research that I would love to do in the South Sandwich Islands, and on Mt Michael in particular. We now know much more about the conditions that equipment would need to withstand, so a key goal for the future would be to develop robust instruments that could be deployed permanently to monitor volcanic activity continuously and send this information using satellite communications. I’m also incredibly interested on the interaction between volcanic activity and the islands’ unique biodiversity, both terrestrial and submarine, and there are discussions in the pipeline for a collaborative expedition in the future that combines biology with volcanology.