Professor John Maclennan
I have been interested in volcanoes for well over 30 years. My research group, in the Department of Earth Sciences, studies magmatic processes. We want to answer simple questions. How is magma generated? How does it move towards the surface? Where is it stored before volcanic eruptions? What is the relationship between magmatism and environmental change?
The business of answering these questions is, however, far from straightforward. We can't get a direct line of sight into the Earth, so we have to use lots of different types of observations to probe these magmatic plumbing systems. During the eruption of Eyjafjallajökull, the Icelandic volcano that caused travel chaos in spring 2010, Earth Scientists monitored patterns of earthquakes and the rapid inflation of the mountain to try to track melt movement under the volcano. These observations helped to mitigate the overall economic effects of the eruption. However, Eyjafjallajökull was a relatively small event: every few hundred years or so Iceland generates an eruption that is 100 times larger. We are therefore faced with the challenge of recognising the signature of a build-up to such large eruptions. How might patterns of earthquakes or deformation of the surface of the volcano change in the weeks, months or years before a big event? Can we develop volcano monitoring systems that will give us advance warning of impending eruptions? Our approach to this question has been to use the rocky products of past eruptions to probe their origins. This discipline is called Igneous Petrology and requires a broad range of skills - fieldwork in challenging conditions, painstaking microanalysis of rocks in the lab, development of physical models of magmatic processes and their solution by computational techniques. Really, its just a neat blend of the options that I took in 1A Natural Sciences over 20 years ago - Physics, Chemistry, Maths and Earth Sciences. My work in this field was recently recognised by the Geological Society of London who awarded me the 2014 Bigsby Medal.
In College, I am responsible for the supervision of undergraduate students who take the Earth Sciences/Geology options as part of the Natural Sciences Tripos. I was awarded one of 2014 Pilkington Prizes and I am also one of the graduate tutors.
Here are a series of links that give a little bit more detail about some of the work that we do in the Earth Sciences Department.
- The Hidden Colour Inside Volcanoes (BBC)
- Earth Science at Cambridge (YouTube)
- Magma Arta: Rocks Under the Microscope (University of Cambridge)