No, we did not ‘predict’ an eruption

The last seven days have been a bit of a whirlwind for me. Not only did I start my new job as a lecturer at the University of Exeter (Cornwall campus), but I had a paper published in Scientific Reports. The paper generated quite a media buzz with all sorts of flashy headlines attached. Unfortunately, not all these headlines were strictly correct – there was definitely some sensationalised exaggeration going on, a point correctly picked up on in Erik Klemetti’s blog about how to be a savvy science-news reader. While my co-authors and I are obviously grateful for our research to get a bit of press, I want to take a second to explain the research and what it means in my own, un-edited words.


A selection of the news headlines…

First and foremost, we did not ‘predict’ an eruption. We never used that word, and we never will. A more common word to use in volcanology, and natural hazards research in general, is ‘forecast’. A forecast differs from a prediction as it includes a certain level of uncertainty, i.e., something MAY happen in some period of time, whereas a prediction might say something WILL happen on some given date (e.g., Friday 13th January 2017). You can think of it in similar terms to the weather, where you get a forecast of what the weather MIGHT do over the next 24 hours (and everyone knows that the forecast becomes less and less reliable as time period goes up – never trust a 5 day forecast, especially in Cornwall!). But enough about prediction vs. forecast – I’ll save that for its own blog post some other time*.

Our paper was about the Sakurajima volcano / Aira caldera magmatic system in Japan. Sakurajima is Japan’s most active volcano, producing regular small and localised explosions most days. However, the eruptive history of this volcano is also littered with more violent and deadly events. A large eruption in 1914 killed 58 people, produced huge lava flows and caused the ground to subside a metre leading to widespread flooding. Of concern to the local authorities now is whether this volcano is likely to see an increase in its current level of activity and produce an eruption similar in scale to the 1914 event.


Sakurajima volcano sits on the southern rim of Aira caldera

To answer this question our research aimed to improve the understanding of the volcanic system. We used data from highly accurate GPS sensors to measure the ground movement around the volcano resulting from the build-up of magma below, and then included data from seismometers and heat-flow measurements. Using advanced, 3D numerical models (that don’t rely on numerous over-simplistic assumptions like the previous models in use) we were able to reconstruct the magma reservoir that feeds the volcanic system. With our approach we could more accurately estimate the magma reservoir location, size and shape, as well as the rate, timing and mechanism of magma supply.

The results matched with other observations and presented a consistent view of the developing magma system – something of a rarity in Earth sciences. They showed that the rate of magma supply was greater than the rate of magma currently being erupted – causing the magma reservoir underground to swell.

Then, to apply our results to some basic eruption forecasting, we took the assumption that for another 1914-sized eruption, the volcano needs to store the same amount of magma that the 1914 eruption threw out – about 1.5 cubic kilometres. Using the magma supply and eruption rates we estimated, and assuming these rates are constant over time (not necessarily true), this would take roughly 130 years from 1914.

So we did not predict when a larger eruption would take place, we estimated the amount of time it would take to store enough magma for a larger, 1914-sized, eruption. An eruption that may or may not happen, or that may happen earlier or later as magma eruption and supply rates change. Our results could even be used to estimate a sliding scale of eruption size with time if all rates do remain constant.


A rough estimate of eruption size with time for a large (paroxysmal) eruption at Sakurajima, assuming all the rates we calculated in our research remain constant, and the entire volume that is stored is subsequently erupted.

Another cool point comes up when we apply our results to a past time period. There was also a large eruption in 1892, and if we use our 130 year timeframe again to accumulate 1.5 cubic kilometres of magma we would estimate a large eruption around 1912 – just two years different to the 1914 event. Not bad, eh?

And that was it **. There were no harbingers of doom in the paper, ‘just’ some fancy new models and application of the results to simple eruption forecasting.


Enjoying the sun and eruptions at Sakurajima in 2013.

* I predict that won’t happen in the next 7 days ;)

** Well, there was actually a lot more that went into the paper, of course. What was equally interesting for us was the fact that our new models provided much better insights (in our opinion) than the models that had been used previously, and these old models have been applied to dozens of volcanoes around the world since the late 1950’s. This leaves plenty of work to be done in the future! Plus more improvements can still be made to the techniques we developed, such is the world of science. Obviously this is not as sexy as apparently ‘predicting’ an eruption, and was not as widely reported by the media.

Two weeks in the ‘Avenue of Volcanoes’

(Originally posted on the Bristol University BDC Blog)

Workshops, conferences, field work – national and international travel is an essential part of many PhD programs. I’ve been lucky enough to see numerous new parts of the globe during my studies, and, less luckily, numerous different airport layovers (I’m currently writing this post from a corridor between terminals at Washington airport…!).

I’m on my way back to Bristol from a workshop in Ecuador on volcanic unrest, which culminated with an eruption simulation exercise. As my PhD is focused on unravelling the science behind volcanic unrest, these trips (this is the second of three with this specific aim) form a main focus for the real-world application of my research.

This workshop was split into 3 different parts. The first was a series of lectures on how volcanologists, social scientists, emergency managers, civil protection officials, and the general public interact during volcanic crises. Each specialist contributed their individual expertise, in my case as a volcanologist interpreting the signals that the volcano gives off, but the main message was that communication at all times between all parties must be especially clear. As with almost all lectures though, this part of the workshop obviously wasn’t the most exciting – especially with the inevitable jet-lagged tiredness kicking in for the first few days.

The second part of the workshop took us out into the field to explore two of Ecuador’s most famous volcanoes: Cotopaxi and Tungurahua. This was my favourite part! These are two quite epic volcanoes with the classical conical shape you imagine when you think of a volcano. By examining them in situ we learnt about the hazards they pose today to many nearby towns and cities. This really helps to put my research into perspective, as I know that by contributing to a better understanding of how volcanoes work I am helping to protect the people whose livelihood’s depend on the benefits the volcano brings them (for example, the more fertile soil).

Cotopaxi volcano. 5897m ASL.

Cotopaxi volcano. 5897m ASL.

The final part of the workshop took us to the Ecuadorian national centre for crisis management in Quito (cue vigilant security checks!). Here we conducted the volcanic unrest and eruption simulation. This is similar in some ways to a fire drill but a whole lot more complicated. Simulated monitoring ‘data’ from the volcano is fed to a team of volcanologists who have to quickly interpret what the data means and feed that information in a clear, coherent and understandable way to emergency managers, politicians and civil authorities. Upon the advice of the volcanologists, the decision makers can then choose how best to respond and mitigate a potential impending crisis. As this was just an exercise, different stages in the unrest crisis were dealt with all in one very busy day, with ‘data’ from the volcano arriving every couple of hours but representing several weeks or months in simulated time.

The final ‘update’ from the volcano: BIG eruption! I think we all could have predicted that – everyone likes a grand finale.

Despite the Hollywood firework finish, these exercises are crucial to prepare those individuals who will actually be in positions of responsibility when a true volcanic crisis develops. By playing out the different stages in as close to real-life as possible, strengths and weaknesses were highlighted that will allow for improvements to be made in the future. Improvements that may just save extra lives or livelihoods, and foster improved relationships between the public and the scientists trying to help them.

As one of those scientists, I was just happy enough to be able to take part.

Tragic Sinabung Eruption

Originally posted on the Between a Rock blog and the EGU blog network.

Last Saturday (1st February 2014) an eruption at Sinabung volcano in Indonesia claimed the lives of 14 people. That death toll has since risen to 16, and could rise further as people battle in hospital with severe burns and other wounds.

A local villager runs from the eruption of Sinabung volcano in Indonesia. Image credit: BBC News.

A local villager runs from the eruption of Sinabung volcano in Indonesia. Image credit: BBC News.

The volcano has been erupting since September 2013 and over 30,000 people have been evacuated from their homes. The Friday before the latest eruption, anxious citizens were allowed back to check on their homes. Many had been sneaking back into the exclusion zone anyway. And herein lies the danger. Despite the obvious inconvenience of being away from home for such a period of time, exclusion zones and evacuations are there for protection and safety. This tragic event is the result of people becoming too complacent around a volcano with a prolonged eruption, and locals not fully understanding the risks associated with such situations.

Hopefully this will serve as a timely reminder, to both locals and scientists. The perennial need for better communication between scientists, locals and civil protection authorities isn’t going away.