Volcanology involves a lot of watching. It has that in common with another science: astronomy. Both are sciences where it is not really possible to do experiments. Instead we have to wait until nature decides to do something, and study events as and when they happen. In volcanology, the event itself may last hours to weeks, after waiting for years to centuries. In astronomy, the time scales tend to be rather longer, with millions of years seen as very fast. But in both cases, the important thing is to watch and learn. The seeing becomes observing, following the century-old call from Sherlock Holmes: “You see, but you do not observe [..] I have both seen and observed”. Holmes was the ultimate observer, while his partner Watson was good in action but failed miserably in observing. His background was in the army – not in scientific detective work.

Observing

Observing means noting the details, seeing what is important, what it shows or indicates. Speculation is allowed, but opinions should be based around facts and the holder should be willing to change them (opinions, not the facts) when new data is obtained. Science challenges knowledge – pseudoscience challenges facts.

“Data! data! data!” he [Holmes] cried, impatiently. “I can’t make bricks without clay.”

What data do we need? That depends on what it is we want to learn. Edgar Allan Poe wrote that “Every mystery begins with a question”. Science begins with phrasing a question, a ‘why’ or a ‘how’. The best scientists are those who asks the best questions, based on their knowledge of the subject and knowing where the gaps in knowledge or understanding are. New discoveries are rarely made blind. They come from research aimed at answering specific questions. Sometimes we do stumble on something new and unexpected, and we may not notice because it wasn’t what we were looking for. The echo of the Big Bang was detected long before two people finally wondered where that excess radio noise came from – and won the Nobel prize. That too is science.

“That, detective, is the right question. Program terminated” (Dr. Lannings hologram in ‘I Robot’)

How do we obtain the data? For Sherlock Holmes, it involved a magnifying glass and a tape measure. For Hercule Poirot, (“the little grey cells”) it involved finding out who said what, a detective who listens, sees how people act and very importantly, asks the right questions, but is not as focussed on physical facts. Miss Marple (“a certain knowledge of human nature”) is cut from the same cloth as Poirot, not surprising seeing that they came from the same imagination, but still states that “One does not like to make definite assertions unless one has a little more definite knowledge”. In all cases, when the data is complete, the explanations become clear. Rather than publishing the case with the data and the conclusion in a scientific paper, judged by the referees, or in a court of law, judged by judge and jury, Hercule Poirot makes the case in a public meeting, crucially without a lawyer, judge or referee present. That is not as scientifically sound, and perhaps on this point Sherlock Holmes lived more in the real world.

“Data is like garbage. You’d better know what you are going to do with it before you collect it.” Mark Twain

Instruments

How do we obtain data in science? Instruments are needed, and another word for instrument is sensor. Indeed, our own senses qualify: eyes, ears and nose are instruments that we come naturally equipped with. But data needs to be recorded and on this point our natural instruments fall a bit short. Our data is stored in our memory and the recall is often fallible. Our remembrance may deviate quite a bit from reality: the data becomes changed over time, may be confused with other events and overwritten by later impressions. Every recall can change the original memory. It has always been important to write down observations immediately.

In astronomy, drawings were made while looking through the telescope, and the brightness of stars relative to other nearby stars would be recorded. The drawings would later be elaborated, with for instance detailed depictions of mythical creatures representing constellations. We still have those drawings even though our constellations have changed over time. In the 19^th century, photographic plates were invented and the chemical data recording revolutionised science. Nowadays, we almost exclusively rely on electronic data recording.

Volcanology has the same issues and solutions. Ancient drawings of volcanoes seem unconvincing to us. Recollections written down much later can be distorted. Eyewitness accounts of eruptions describe how events unfolded, but they often miss parts, because of cloud cover or the eruption cloud itself. As for hearing, the sound of an explosion may seem unmissable; for Hunga Tonga, it was heard across the Pacific ocean. But at ten kilometer from an eruption, the eruption may remain completely silent. The people who saw St Helens explode (and survived) did not hear it. The sound waves bend away from the surface, giving a silent zone – the same zone that causes the lightning of distant thunderstorms to be visible, but their thunder to go missing.

In contrast, the lava and or tephra produced by an eruption may remain present for a long time. So the first instruments that a volcanologist needs are a pair of solid hiking boots (volcanoes are rarely found in easily accessible places, often for obvious reasons), a hammer (not for liquid lava: if you see a picture wth a geological hammer being used on liquid lava, your AI filter is set wrongly), an essential accessory to show volcanology is just geology in action, a magnifying glass and that essential, rare ingredient, an adequate travel budget.

What other instruments are used? There are many, at a variety of cost levels. Cameras record the eruption, ideally remote, automated and continuous. Ideally they should be robust enough to survive whatever the volcano throws at them but that is optimistic. Remote imaging from satellite is now common. The low-orbit high resolution satellites are not continuous, since each satellite may only cross over a particular volcano once every few days. Weather satellites do give continuous coverage, bt at low resolution – they were the one who caught the major eruption of Hunga Tonga in the act. Satellites are very expensive, but they have many users with bigger budgets and volcanology can ride piggy-back and doesn’t have to pay the bill. Infrared imaging can follow eruptions in progress – that is often limited to satellites as such cameras are expensive and it may be unwise to leave them unguarded in the wild west of erupting volcanoes.

The cameras replace looking, with the advantage of continuous coverage and certified recall. But instruments can also measure many other things our eyes can’t.

Volcanoes bring up magma and turn it into lava. There is no net change, apart from some change in density as the magma cools. But while it is coming up, the ground rises – and that is something instruments can detect. There are several ways to do so.

The first way measures the change in tilt at some distance from the volcano. An inflation of 1 mm at the volcano will cause a change in tilt at 1 km (hopefully a safe distance) of one part in a million – one microradian. A tilt measurement uses a base length of 1 meter, and in this case it will see one end going up by 1 micron compared to the other end. The accuracy of a modern tilt meter can detect this quite easily. There are some problems, however. If the magma is coming up right underneath the instrument, it will go undetected since there is no tilt there. And there are many other things which can cause tilt to change – such as heating of the ground by the Sun -known as ‘day’ – and changing water content of the soil – also known as ‘rain’. In the current eruption at Kilauea, the tilt changes are far larger than 1 micron, and they have turned out to be a good predictor of the start of the next episode. But this is unusual.

Nowadays, inflation can also be measured directly using a GPS system. That allows a series of measurements to be taken at various points around the volcano. It depends on GPS satellites – paid for by the US government (and received with thanks!). They are not as accurate as tilt measurements, but are much more informative. It typically needs a few days to detect a change with a good degree of confidence. At Kilauea, HVO also uses them to measure the changing length across the caldera, using two GPS stations on either side.

A third way is by using radar, from a satellite or aircraft. The return signal measures the distance, and by doing that over a period of time, it produces a map of where the ground level is changing. It assumes that most of the mapped region will not change (otherwise the method does not work as well), so that it picks out the smaller regions (maybe a few kilometers across, but can be smaller) where inflation occurs. It may work poorly at small volcanic islands, but it works well for volcanoes on land. Measurements take long, so it may take weeks for a useful map of changes to appear. Again, these radar satellites are provided by governments – at the moment mainly the European Union.

(There is actually also a cheaper way to find inflation. An inflating volcano can depress the water table, because it opens up faults which let the water drain away. Mayon is well known for this, with water wells drying up in the months before an eruption. The drying-up may also have been the reason for the abandonment of Krakatau in the decades before its major eruption.)

Volcanoes produce not just lava. They also produce gas emissions, and these can precede an eruption. Two are especially important: SO2 and CO2. CO2 is produced in deeper magma, and can trace magma at kilometers deep. SO2 comes from shallow magma, and is closer related to an eruption. Both can be dangerous. Water is also produced, but is in itself harmless. CO2 can be hard to measure because it is also naturally present in the atmosphere – and we ourselves have increased its abundance by 50%. SO2 is easier to detect. It can be measured using spectrometers on satellites, or by directly collecting gas and measuring it in the laboratory.

With all those expensive (and bulky) instruments, that cheap rock hammer can still come in useful. The composition of the lava is based on where the magma formed, and it can form a fingerprint which is different fir different volcanoes and can even differ between eruptions from the same volcano. The broken bit of lava, extracted using that hammer, can be taken back to the laboratory to measure the amounts of many different elements.

Scientists love to try out new things, and are always looking for or designing different instruments measuring different things. But the list above is a basic set of commonly used instruments.

“It is a capital mistake to theorize before one has data” (Sherlock Holmes)

So now we have data. We are drowning in it. What do we do with it?

People

Countries with active volcanoes tend to have volcano observatories. They may be part of a geology organisation (as in the US), part of weather forecasting (as in Iceland), or both (Guatemala), be part of a disaster management organization (Guatemala) or stand on its own (as in the Philippines). They may be for a specific volcano (as in Italy) or cover the full country (Philippines, Iceland). Earthquake hazards and volcanoes may be covered together (New Zealand, Philippines) and research may be separated from monitoring (Japan) or included (US). For unclear reasons, aviation (concerned with ash clouds) uses a separate list of responsible organisations. But the basic idea is that for each volcano there is an organization tasked with looking at the data, hopefully with a red phone line to the relevant authorities!

This is crucial. Data in itself is meaningless. It needs to be interpreted, by people with in-depth knowledge and recognized expertise. Too many people love predicting disaster, and too many people believe the eye-catching predictions of catastrophe. Tabloids, X, and such, are not sources of reliable information, but they can easily drown out the voices of reason. The task of the observatories is to analyze the date, create a picture of on-going events and from that extrapolate to possible developments – with all the uncertainties that involves. Finally, they distill this into a story which is true and is understandable to the population. People do not understand data – but they do understand stories. Without the volcano observatories and the people working in them, the information hiding in the data is lost.

“Data are summaries of stories—telling those stories makes the data meaningful.” Dan Heath

But there may be conflicts here. Observatories need funding, and most of the time volcanoes do not repay the money. They just sit there, biding their time. At a time when money is scarce, volcano observatories can be an easy target for cost cutting, also known as ‘efficiency saving’. (Savings more often than not tend to reduce efficiency, but that is a different point.) A minor explosion from a minor volcano (Eyjafjallajokull, 2010) cost the global economy an estimate 5 billion dollars, almost entirely because it closed Atlantic air space for ten days. But that is long forgotten. Volcano observatories either need to convince their volcano to misbehave, or need other arguments to convince funders.

The level of funding that is available varies greatly between countries. That affects the people working at the observatories, who may be fewer than ideal, and it affects the instrumentation that is available. With the cost of instruments in the ten of thousands of dollars, and a network of instruments costing ten times as much, many volcanoes will be under-monitored. Drones may nowadays provide a more cost-effective way (‘efficiency saving’) for basic monitoring. But getting the right people in can be more challenging. It is important that those people are locals, speaking the language and knowing the audience. They need to be trained, ideally within the country. Science is highly international and people move easily between countries. Once a student studies abroad, they may not come back.

Here lies the first task of a local volcano observatory: ensuring that the right people are trained in the right way. It involves making those people interested in the topic in the first place, and afterwards ensure that the training opportunities are available to them. Many people may not continue, but that is ok if their training is useable elsewhere in the country. People with data skills are a valuable commodity. So of the funders are not that impressed with the need to keep close watch on that obviously deeply dormant volcano, here is another motivation: volcanoes (with a little help) help build up the human capital a country needs. It means talking with children, and partnering with schools and universities.

It may also be useful if the instrumentation that is required can be made locally (‘grow the economy’), but for specialised instruments that may be hard. Still, trying doesn’t hurt.

“Good advice is almost certain to be ignored, but that is no reason for not giving it” – Jane Marple

Jodrell Bank

That brings me to quite another matter. For volcanology is not unique. Astronomy too has observatories, and it too can have problems keeping them funded. (Unlike volcanology, astronomers do still build observatories on volcanoes. Volcanologists stopped doing that a long time ago.) We run one such observatory: Jodrell Bank, well known for the Lovell Telescope, a 75 meter radio telescope that dominates the local landscape. It is famous for tracking Sputnik, for the first image of the surface of the Moon (eavesdropping on a Soviet satellite – the Soviets made sure it could not happen again), for mapping the radio sky and for studies of pulsars. But it is itself also a quite magnificent sight.

But all is not well. The funding for the observatory, amounting to 2.8 million pounds per year, is being withdrawn from 2028. The telescope will fall dormant and 28 people will lose their job. This had led to quite an outcry in the UK, as Jodrell Bank has long been a poster child for UK science and has a long history going back to the cold war. It is a UNESCO world heritage site (specifically described as a ‘living heritage’ as of course science in action constantly redesigns its environment), and the visitor centre attracts well over 100,000 people each year. The science funding is relatively minor, but once gone the site is no longer an active observatory and that can’t easily be undone.

Why keep it alive? Why not let is become a museum, retaining the visitor attraction but ending the research? How much is it worth to keep it open? How does one compare cost against value? The university is pretty clear. The brand has significant value to it, and closing the observatory would damage the brand. But that is not something that is likely to sway the funders.

One of the arguments revolves around the importance of science to the UK. The UK is world leading, and the country presents itself as a science powerhouse. It is as much part of British culture as is its music. What does it say about a nation to turn its national observatory into a mausoleum? Jodrell Bank has a great cultural significance: it shows the direction of travel of the country, perhaps moving away from technology.

One does not have to be an astronomer to know that optics matter. (Guardian, 31 July 2026)

One can also point at the long-term impact. Radio astronomy started the “big data” revolution. Jodrell Bank handles 210 Gb of data every second. A special computer was home-build to handle the data rate – it was not something that could be bought of the shelf! Further back in time, wifi was invented by and for radio astronomy. Scientists are unpredictable. You never know which of their ‘let’s try this’ ideas will get wings.

And last, do point at our young people. Tens of thousands of them visit the observatory and its discovery centre, from quite diverse backgrounds. It is an inspirational place, and inspiration can lead to the perspiration needed to tackle the hard subjects at school. It is how human capital grows. But the inspiration comes from the live science, listening to the telescope signals as they are received and seeing the big dish move towards its next target. Museums teach respect for the past, but cannot compete for inspiration for the future. That is the living heritage Jodrell Bank has been aiming for.

Things are up in the air. Jodrell Bank will have to change either way. But it would be much preferable to change to a better future rather than a magnificent past.

Albert, August 2026