Words by

James Ashworth

Sigh. If I had a penny for every time someone has made that joke when I tell them I study ‘volcanology’ (or worst still, ‘vulcanology’) then Iceland would not be in debt right now. And neither would I. So allow me a few minutes, if you will, to persuade you that yes, volcanology is a real science and no, it’s nothing to do with pointy-eared science fiction characters!
WHO STARTED STUDYING THESE THINGS?
The beginnings of volcanology as a science can perhaps be traced back thousands of years. Back in 79 AD, Pliny the Elder recorded the series of events leading up to the huge eruption of Italy’s Mt. Vesuvius, which of course famously decimated the Roman town of Pompeii. His nephew, Pliny the Younger, took over after his uncle died from gas inhalation. Their letters are considered so important to the field of volcanology as a whole that they have a major type of eruption named after them—so-called Plinian events.
In the following centuries little advance was made due largely to religious beliefs, but some important observations were made such as the first recording of a pyroclastic flow (a fast-moving flow of hot gases, ash and rock most commonly generated by explosive eruptions or collapse of certain features). However, it would not be until perhaps the mid-20th century when the science of volcanology would really begin to take off.
THE BEGINNING OF THE BEGINNING
The first major building block came in the form of Plate Tectonic theory, which gathered large-scale acceptance within the scientific community during the 1960s. This divided the Earth’s crust into many large ‘plates’ that drifted about on the surface, presumably driven by forces within the Earth. New crust was created along some edges and old crust was pulled (subducted) down into the Earth along others. In some areas two plates simply slid past each other. These three types of ‘plate boundary’ explained many types of geophysical and geological activity including earthquakes of different kinds, mountain formation and of course volcanology.
As the science grew, more detailed explanations began to arise as to why certain volcanoes developed at certain places. Explosive volcanoes were often constrained to areas where subduction was taking place, whereas volcanoes producing more fluid lavas and spectacular fire fountains were often found on or near boundaries where new plate was being constructed. However, there was still one great riddle—why were some volcanoes right in the middle of plates?
IS IT HOT (SPOT) IN HERE, OR…?
An explanation for these isolated volcanoes was proposed in 1963 but it was not until some years later, following the general acceptance of Plate Tectonic theory, that more detail was put in place. The general idea was that there was a ‘hot spot’ on the Earth’s surface, for whatever reason, which was causing melting where there shouldn’t be any and therefore triggering volcanism. In fact, coupled with plate tectonics, it appeared that the hot spot was not fixed to the plates—rather, their origin was somewhat deeper. As the plates moved on the surface, the hot spot remaining in one location, creating a chain of volcanoes on the overlying plate. Perhaps the most famous example of this is the Hawaiian Islands, lying right in the middle of the Pacific Ocean—far from any plate boundary—but there are many others worldwide.
In fact, this hot spot theory can be used to explain much of the volcanism in Iceland, too. Here the hot spot lies almost directly beneath a constructive plate boundary, so rather than creating an isolated area of volcanism it instead supplements the activity already going on along the ocean ridge.
BUT WHY DO THESE HOT SPOTS EXIST?
Truthfully, we don’t really know. There are many theories, one of which is generally far more convincing than the rest. The generally accepted proposal is for ‘mantle plumes’—rising columns of hot material within the Earth’s mantle (the layer beneath the crust). But there is still a lot of argument as to why exactly they are there and even where they originate. Some believe they begin near to the Earth’s core while others believe they are much shallower. Further work is needed to answer these questions and that work will itself surely raise more questions than it answers—the ongoing cycle of scientific research continuing as ever!
BUT WE REALLY KNOW A LOT NOW, RIGHT?
Well, we certainly know a lot more than we did 50 years ago. However, we just keep figuring out new things. Stuff that was practically taken as being scientific fact some decades ago is now proven to be wrong. For example, when Mt. St. Helens blew up so spectacularly in May 1980, collapsing and blowing out a whole side of the mountain, we thought that was an isolated incident. But the more we look at other volcanoes worldwide, the more we see that this is actually a relatively common event.
Far from being of interest to just the scientific community, such advancements in the science can actually bring huge benefits to the general public, too. As we learn to better understand volcanoes we also learn to better prepare for eruptions and to guess at what they may do in the future. Indeed the science of volcano forecasting and prediction is a rapidly advancing one and I feel privileged to be able to work within that field. From next year I hope to be working on Sakurajima volcano in southern Japan, where some stunning science is being done—they have even developed a system that can predict regular eruptions with a good degree of accuracy. This is something we would never have dreamed about some years ago!
The science of volcanology is an imperfect one. Volcanoes can never be perfectly predicted or fully understood, but we can try. And try we must, because with a growing global population, more and more people will be exposed to the hazards associated with volcanoes. Now, more than ever, volcanology is truly at the forefront of protecting the public in many countries—something many Icelanders will be all too familiar with.