Volcanology, Simon Halliwell @Shalliwell91: A Day in the GeoLife Series

NAME:  Simon Halliwell

CURRENT TITLE: Seeking opportunity

CONTACT INFORMATION:  [email protected]

AREA OF INTEREST:  Volcanology and Geological Hazards

EDUCATION: MSc Volcanology and Geological Hazards Graduate, Lancaster University, United Kingdom


Las Canadas Caldera. Photo copyright: Simon Halliwell

What’s your interest?

As you may have guessed by my degree, I am fascinated by volcanoes, particularly how powerful eruptions can be and how gas escape can lead to changing eruption style, but is also a tool used in volcano monitoring.

Volcanic eruptions are driven by the expansion of gases within magma, and it is the ability of these gases to escape which governs the explosivity of an eruption. So, if sufficient amounts of gas escapes, the volcano can become less violent.

What’s your research experience?

I studied the 2008 eruption of the Chaiten volcano (located in Chile) for my masters research project. This eruption changed from an explosive eruption producing ash and volcanic bombs to an effusive, lava flow producing eruption after around two weeks. I studied a volcanic bomb from the eruption which contained many fractures that gave a clue into how gas may have escaped from the once molten magma.

Work in the lab using a Fourier transform infrared spectroscopy (FTIR) was used to detect water within the bomb and showed how it had diminished (as vapour) into fractures during the eruption and escaped. Models could then be used to estimate the amount of gas lost from the magma and observe whether this mechanism of gas loss through fractures controlled the eruption style. However, results were inconclusive since bubble growth and coalescence may have also played a role.

I used a hot-stage microscope at Lancaster University to melt pieces of the bomb to increase our understanding of how and why bubbles formed in the bomb. This was either due to cooling or lack of gas to cause growth by diffusion. These were super cool experiments just because I had the chance to melt lava and not many people can say they’ve done that!


Taking CO2 flux measurements. Photo copyright: Simon Halliwell

After leaving university, I’m still pursuing a career in volcanology and have recently been on an internship to Tenerife where I participated in current volcano research on Mount Teide. Here, I conducted diffuse degassing surveys of carbon dioxide (CO2) and other volatiles with a team of scientists from INVOLCAN (Institute of Volcanology for the Canary Islands) and other interns, both at the summit and on the rift zones around the volcano.

In situ CO2 efflux measurements were taken using the accumulation chamber method (see picture above) and soil gas samples were extracted via a probe and injected into vials for future analysis in the lab. Measurements of CO2 flux were taken because this is the second major gas species to degas from magma after water (H2O) and an increase in efflux could indicate magma intrusion at depth. However, the recorded flux at a given site may have a significant biogenic component (attributed to the decomposition of organic matter in the soil) which requires analysis, and this is where the gas samples come in. Using isotope ratio mass spectrometry (IRMS), it is possible to distinguish the source of CO2 by calculating the ratio of C-13/C-12 within the gas. The composition of soil gases collected in vials were also analysed, particularly for signs of helium. Helium (He-3) is the best geochemical tracer of magma intrusion, as it is an inert gas sourced from the mantle. Consequently, if there is a high ratio of He-3/He-4, then we are more or less certain magma is present beneath the surface and indicates a risk of eruption.

The scientists at INVOLCAN conduct these surveys every summer as a way of monitoring volcanic activity and reducing risk to the thousands of inhabitants. They also monitor earthquakes as indicators of magma movement and use the global positioning system (GPS) to observe any possible inflation or signs of flank movement. They are always looking for interns, so if you’re an undergraduate or recent postgraduate check out GeoTenerife to see how you can get involved!

So, there are some of my research experiences! I’m still looking to start a career in volcanology, so if you’re reading this and could hook me up with a contact, get in touch!

What’s fun?

The most fun I’ve had is being lucky enough to see a volcanic eruption! This is one of the most amazing spectacles on Earth. This was during a field trip to Mount Etna which put on an amazing strombolian firework display!

The field work aspect of volcanology is what I enjoy most because you get to see amazing landscapes and evidence of volcanic processes for yourself — all this while also having a laugh with your coursemates and doing some hard work at the same time.


Mount Etna eruption, April 2013. Photo copyright: Simon Halliwell

What’s challenging?

What I have found challenging is having to plan and execute a dissertation project. Something inevitably will go wrong, so you need to allow extra time to re-do experiments, for example and make sure you know all the tasks that you have to do within a given time.

From my experience of working on volcanoes, particularly Mount Teide, you need to be fit and able to walk across difficult terrain while also being able to cope with the altitude.

What’s your advice to students?

My advice to students thinking of becoming a volcanologist is to decide what you want to specialize in (e.g. petrology, geology, geochemistry, geophysics) and pick a degree which contains these modules. If you are younger and don’t really know yet, then just do as many science subjects as you can and maybe a geographical science. Most of all just follow your passion and work hard!

Thanks for reading!


Mount Teide. Photo copyright: Simon Halliwell

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