I am always looking for ways of innovating my teaching and attempting to come up with new ideas to communicate the material and ideas to students. So here is one such idea which initially stemmed from some teaching I delivered on planetary volcanology but that I now use across my volcano teaching. The idea is an acronym 'MAGATH' which, when used, (maybe!) helps us to understand volcanic processes throughout the solar system, in terms of how the volcanic activity is generated and the volcanic products or phenomena which may then be produced, along with some of the major controls on volcanic behaviour. So here it is, MAGATH, and what each of the letters stands for:

M is for Material. Here we get to the crux of the matter straight away, not all volcanic activity has to be molten rock, indeed, there are several planetary bodies which exhibit ice-based volcanism. Within this we can also have significant variety of rock or type of ice. For example, on the Earth we have basalts, a low-viscosity rock when molten, which commonly exhibits low explosivity styles such as strombolian or lava flows OR we could have a rhyolitic magma which may present in far more explosive Plinian styles of behaviour. There are of course a large number of possible types of material, and nuances to this, but the first step is the understanding that these materials can vary greatly (and themselves have varying properties related to things like silica and crystal content) and can then subsequently effect the volcanic activity type or phenomena which occur. 

A is for Available Gases. The gases which are contained within magmas are one of the major drivers of explosive volcanic behaviour. Beyond this we can then begin to probe into what types of gas there are, the major constituents on Earth being water, carbon dioxide, and sulphur dioxide, amongst a number of other gases. These gases form bubbles within magmas, it is how these bubbles behave and interact within the conduit which can then lead to the variety of styles of activity that we see at the surface. If we were to take a basaltic magma and add a certain amount of gas to the mix, what style of activity would we see? If we had only enough gas to produce small millimetre sized bubbles we may produce passive degassing, if we were then to grow the size of bubbles in a basalt to metres in length we could generate strombolian activity.   

G is for Gravity. Have you ever seen the plumes of Io (a moon of Jupiter)? Gravity plays a role in their height and trajectories. How far will a lava flow travel? How high will an eruption column be? Gravity plays a key role in all such questions. Gravity also links very closely with the theme of the next letter A.

A is for Atmospheric Pressure. A great example here is to compare the atmospheric pressure of Earth (around 101 kPa) to Venus (around 9300 kPa). Atmospheric pressure will effect the rate of exsolution of gases from a magma, this is the formation of bubbles as a magma rises to the surface. A higher surface pressure means that more bubbles can stay dissolved within the magma, and as gas is one of the major drivers of explosive behaviour this means that we need a higher gas content for magmas on Venus to generate explosive behaviour. Coupled with this, if any activity were to occur, the volcanic products, an eruption column for example, wouldn't reach the same height as on the Earth, this is directly related to the thickness of the atmosphere (which is related to the pressure). Another good example is comparing the trajectory or distance of a volcanic bomb, on the Earth a bomb is subject to a number of forces (air resistance, gravity etc.), at a location such as the Moon where there is little to no atmosphere AND where gravity is lower, a volcanic bomb could travel further. 

T is for Tectonic Environment. This one is key and is intrinsically linked with Plate Tectonics. Roughly speaking we can attribute certain styles of volcanism to certain tectonic environments (e.g., spreading margin, subduction zone, hot spot), we can then build an expectation of style of activity we may expect, so with a hot spot in an oceanic setting (oceanic crust) we may expect more basaltic style behaviour, such as the Hawaiian island chain, whereas at a subduction zone we may expect more explosive styles of behaviour perhaps related to the production of ashy eruption columns. 

H is for Heat Generation Mechanism. Volcanism or volcanic activity is, simply put, some form of surface evidence or product of the heating of material (see the link back to the first letter 'M', what material has been heated!). The question is then, what is the mechanism of heating? We can broadly narrow this down to two main mechanisms, the radioactive decay of isotopes and tidal forces. 

​So, MAGATH aims to help students identify: the key factors which act to control style of volcanic activity, how the activity may behave in the atmosphere, and how it is generated. It can then become a framework to build other content around, as needed, and importantly these factors interact. And of course there are many complexities which effect volcanism beyond the examples given here, which are just a flavour. To delve into more I would have to write a book! There are already some great existing volcano books around for more detail and elaboration though. Anyhow, I hope this may be of use, after a quick google the other common use for 'MAGATH' is a German football manager, so all good on that front. ​I also think it is quite similar to the word 'magma' so could be easier to remember, who knows whether this is actually true or not!

As long ago as October 2016 and January 2017 (in academia this really does feel like an age!) I wrote about my ongoing work with colleagues at Sheffield on developing a low cost method for measuring sulphur dioxide release from volcanoes. This work has somewhat 'exploded' since these initial posts, enough that the University of Sheffield media team decided they wanted do a little video feature on it (see below). Here is a little quote from this video by yours truly:

That's just it, from an idea, which I seem to recall was hatched in the pub out of necessity, to a working instrument which has now been lent to people for work across the globe and has even been picked up by NASA, all in all, very exciting!

During this time we have developed the cameras, from duck-taped monstrosity measuring sulphur dioxide emissions at Drax Power station, through to slightly less duck-taped monstrosity camera at Etna. We finally had a boxed and robust version for work at Masaya, and in recent work we have adapted the cameras to operate from mobile phone batteries and be charged using solar power! We have now got to the exciting stage of distributing and lending our equipment out to collaborators across the globe (see above graphic), which has led to a well travelled PiCamera (our affectionate but functional name for the Raspberry Pi UV Camera) and some exciting developing science. Our work was also recently picked up by the Hackspace magazine which involved an interview with the volcano group here at Sheffield. 

​Overall, it has been a relatively quiet summer on the fieldwork front, but I finally managed to get a paper I had been working on for a while out into the world: "Periodicity in Volcanic Gas plumes: A Review and Analysis", this paper tells the story of the patterns (periodicity) we have detected (up to this point) in measurements of gas release and starts to synthesise the meaning of some of these. 

Spectacular Yasur just about sums it up. An archipeligo of islands in the Pacific, Vanuatu is home to some of the most unique and interesting volcanoes worldwide, including my target destination, Yasur. I am paticularly interested in a style of volcanic activity termed strombolian, that which is driven by large bubbles that ascend and burst at the surface. A style of activity I have written about lots before. Yasur is unique because of the frequency that these explosions occur and the number of vents at the summit which produce activity. The archetypal Stromboli (see post here), produces activity from 3 or 4 vents every 5 - 10 minutes (ish), this of course varies. Whereas at Yasur explosions were coming from more than 5 vents (it was difficult to tell how many exactly) and occurred more frequently, from seconds aparts to just a few minutes. So, two volcanoes with a potentially similar mechanism for driving the activity but visibly different behaviour at the surface, a perfect reason to study Yasur, all thanks to a Royal Society research grant.

​The journey to Vanuatu was a lengthy one from the UK, with stopovers in Singapore and Brisbane, before arriving at the capital Port Vila. A few days in Port Vila to acclimatise and sort out officialdom then off on a short internal flight to the island of Tanna. Arriving at Tanna really felt remote, perhaps not as remote as up near Sabancaya, but the tiny concrete airport building and vast lush green forests (I want to call them jungle but not sure I can) were quite something. Picked up in a 4x4 by our lodge owner, its a short 1 hour excursion across a mixture of paved, roads in progress, and dirt tracks. The approach to our 'jungle huts' crossed the ash plane created by the frequent explosions and as we neared the volcano I experienced the familiar buzz of visiting a new volcano.

It has been a mad period of time after getting back from Peru, hence the reason it has taken so long to write this last post! It was a great last few days at the workshop, spending the last couple days listening to some talks and instructing on the use of our Raspberry Pi ultraviolet cameras. One evening we had some telescope time at the hotel we were staying at, pretty cool looking through and seeing the four Galilean moons around Jupiter which was clear enough to see the striping!

On our last day in Yanque we had planned to head back up to Sabancaya to get some more data, but alas, the weather Gods were against us, and it still involved a really early wake up time, before 5 am. Plume in the wrong direction and clouds over the summit. Thats the way remote sensing is sometimes! See the video blog below. In all I think we got some decent data from the first day of fieldwork, so not a disaster but its always good to get as much data as possible. A little disappointing but it did mean a visit to Colca Canyon! Quite an impressive area to visit with some condors thrown in too. After this straight back to Arequipa. Heading back down to Arequipa was actually a huge relief on the lungs as far as oxygen content was concerned, but certainly not for all the pollution! A relaxed time for about 24 hours before the trip home, which was a little unorthodox to say the least. Certainly learnt a few things about booking flights for the future, and certainly worth keeping in mind for an upcoming Vanuatu trip, must buy those flights soon.

Flights on the way home should have been - Arequipa to Lima to Amsterdam to London Heathrow. So, off to flight number one, at Arequipa discovered a 30 minute delay on our flight to Lima, leaving us an hour to connect to a different flight, this sounded tight to us (me and Tom)...but we were assured this was enough time and were even given row one seats. Pretty sure we sat next to a Peruvian footballer and someone who behaved like a politician. They were personally greeted, this is all the evidence we had, definitely concrete sightings. Landing at Lima, up like a flash, and....we had the joys of the bus journey to the terminal followed by a 10 minute wait to collect bags. Legging it from the domestic terminal to the check-in desks, we were too late. Shuddering to a halt in front of the security cordon we were stopped by a guy with a lanyard who immediately looked at us, stated "KLM - follow me!" and he was off at speed! Assuming that this guy was waiting for us we followed at a matched pace, until some alarm bells started ringing...guy tried to grab my bag to start wheeling it, we were moving away from the terminal, and he even started to get a little agitated when we questioned him about officialdom., pointing at his faded plastic lanyard. A brief return to the terminal showed us that the check-in was closed (in fact we would have struggled to make it if the flight was on time!), we therefore decided to follow, at an increased distance, until it appeared the guy was probably legit and we ended up at airport offices. After an hour of haggling and negotiation we knocked down a 10 day wait for a return flight (mental!), £4000 each for business class the next day, to flights 5 hours later with a lengthy Atlanta layover. 

Anyhow, we got back, eventually, and that was it for Peru. Overall, an incredible experience and one I hope to repeat very soon.

So we set up with our sulphur dioxide measuring ultraviolet cameras to get some data. See the video whilst up at the summit. After an hour(ish) of data, the clouds came in starting to obscure the summit, we decided to head back down. For me this was great as the lack of sleep mixed with lack of oxygen at altitude I think was starting to take its toll. ​
On the way back, we stopped at a little village where one of the Felipes spotted a random building which appeared to be a shop. In we went to get sustenance as we were ill-prepared and didn’t bring lunch. Here me and Tom discovered Inca Cola, a little like Irn Bru but slightly less sweet and super tasty. This is also where I started to feel a little unwell. It was difficult to tell whether this was a result of exhaustion and lack of sleep or the start of acute mountain sickness or caffeine withdrawal or a mixture of everything. A small amount of nausea and a mild headache. Some coca cola (not the Inca stuff!) started to settle my stomach so the nausea passed quickly, as did the headache. Over the next hour we descended rapidly, the mild symptoms fully passed and I just felt exhausted.

​The evening was filled with dinner and an icebreaker to the workshop we are piggy-backing along (more in another post). I was probably not at my most chatty whilst mingling! A quick dinner then asleep by 8:30. And so ends Day number 1, which felt more like 3 days. I wrote this lengthier post than usual on the way up for Day 2 which you will hear about soon! See the accompanying video diary below.

​The longer title of this post reads – “Out and about in Tanzania: the wanderings and musings of a volcanologist on an international development fieldtrip”. Why is a volcanologist on a human geography fieldtrip you may ask... The short answer is the desire for a more well-rounded look at international development issues which may include environmental concerns and that someone was needed on the ground to help with this. As ever, the longer answer is much more complicated and boring. So, here I am, sitting on the porch of my room (with a nice king size bed), being bitten mercilessly by every insect which passes. Apparently, all my super strength bug repellent does is attract more of the creepy crawly critters.

This is my first experience of Africa, and wow, it doesn’t disappoint: happy smiling children shouting and waving (check), bus stuck in the mud with locals pouring out from everywhere to help (check), some of the friendliest happiest people I have ever met (check), encounters with completely safe animals like scorpions (check), other interesting critters like the praying mantis (check), lots of Arsenal/Chelsea/Man Utd fans (check), and see one of the most iconic volcanoes on the African continent in Kilimanjaro (check). Still lots more to come I am sure, with a safari tagged on to the end.

Unfortunately, this is not a completely social trip (I am working, honest!) so there have been work items to fill up my time, teaching students to look at the properties of water and soil has been a focus. But, as I mentioned this is a predominantly human geography fieldtrip so I have been exposed to and accompanied students whilst conducting interviews, which means I actually have to speak to and interact with people (breaks out in cold sweat), something which is completely foreign to me and my volcanic gases. Surprisingly, I have actually really enjoyed this and found this a really valuable personal experience. After a crash course on interviewing prior to leaving, I have done my best to provide feedback to students “in the field”. A very different experience to my usual hiking up a mountain, instead wandering round villages looking for locals to speak to with the help of guides. Note to self, if a local is irritably chopping a machete against a pole, don’t ask for an interview. The whole trip has really opened up my eyes to international development issues and got me thinking about its successes, failures, and the extent to which it benefits locals.

One of the more memorable moments was during an interview with someone who has worked in the Kilimanjaro national park, but who was now retired. They were one of the friendliest and knowledgeable people I have met, but not conducive to a good interview (yes, I now know some of the key factors, I wonder, am I a jack-of-all-trades or a master-of-none?), which was aimed at soliciting information at tourism. Classic rambling answers and interruptions from randomers, we even gained some great advice on marriage, growing vegetables, and metaphors on stages of life! I was most disappointed that I was labelled as “midday” and all the students “sunrise”.
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Today is the end of the research stage, so things slow down for me slightly. A visit to nearby Moshi tomorrow. I am not sure whether I should be horrified or not, but someone actually told me “we will make a good human geographer of you yet”. Perhaps I need to climb a mountain soon and do some science, I wonder if there is one nearby…

The above is probably what I wish I had called one of my recently published papers, which have looked at the behaviour of large gas bubbles which ascend and burst at the surface (I'll make an amusing title a future career goal...). 

To understand more about the eruptions we see at the surface we have to investigate what we can't see below the surface and then try and make links between the two. A lot of my work has focused on one style of behaviour in particular, that of strombolian explosions. Strombolian explosions are likely driven by large gas bubbles which we call Taylor bubbles or gas slugs, named after one of the authors in the following paper (Davies and Taylor, 1950). The archetypal location for strombolian activity is on the island of Stromboli, but similar styles of activity also occur at other locations. A lot of work has been put into understanding the dynamics of single Taylor bubbles ascending in conduits, however, far less has been done for multiple Taylor bubbles ascending in close proximity and which may interact during ascent. This is what my recent paper "The dynamics of slug trains in volcanic conduits: evidence for expansion driven coalescence" begins to investigate through the use of analogue experiments (see video below for 30 s clips of the experiments which were shot using super-slow-motion cameras). These experiments were inspired somewhat by activity I observed and investigated in 2012 within the Bocca Nuova crater of Mt Etna. In particular, we were interested in the ability for individual Taylor bubbles to interact and join together during coalescence, and how this may have affected the distribution of each bubble.  For more information on this work see the paper here, which is open access!

The other paper published "Combining Spherical-Cap and Taylor Bubble Fluid Dynamics with Plume Measurements to Characterize Basaltic Degassing" involved the construction and illustration of a brand new model which describes the styles of activity we see at volcanoes such as Stromboli based on the ability of bubbles to interact and the time separating each individual burst at the surface. The aim of this paper is to bring together observations of gas emissions and explosive activity at the surface with the behaviour of bubbles as they ascend in the conduit at depth. This paper can be found here, and is also open access.