Jon Trevelyan (UK)
Notwithstanding the somewhat daunting use of the word “geophysics” in the title, this is another great book in Dunedin’s Introducing Earth and Environmental Sciences series of guides. In fact, that term may well discourage all but the most enthusiastic Earth Scientist. However, as Peter Styles writes:
“If you want to learn what is beneath the Earth’s surface, I guess the obvious thing to do is drill a hole; but the deepest borehole to date, at just over 12 km, is on the Kola Peninsula in Russia, which is certainly a long way down; but this is rather like a doctor sticking a pin in your hand just beneath the skin and trying to work out how the body works”.
And, as he also says “a borehole tells you absolutely everything about absolutely nowhere”!
Therefore, the only real way to understand the Earth, in all its large and slow-moving immensity, is to study its physics and that means using the classical disciplines of heat, gravity, magnetism, electricity, vibrations and waves. That is, everything we know about the deep Earth has been learnt from geophysics.
In this way, the guide discussed the composition of the Earth, its geothermal heat flow and the forces driving plate tectonics, which make the Earth a dynamic system – this, together with seismology and seismic exploration, the Earth’s magnetic field and its implications, its electrical properties, and gravity in connection with the structure of the Earth.
But what are the practical applications of geophysics?
It is clear from a chapter entertainingly entitled “Geophysics goes to work!” that it plays a significant role in surveying for hydrocarbon and mineral resources. In addition, it is a fundamental tool in looking for hidden dangers beneath the surface, such as caves and old mine workings, and for managing pollution and environmental hazards. In recent years, it has also played a role in the search for, and the monitoring of, safe and secure places to store our industrial waste, such as CO2 and spent nuclear material. That is, popular perceptions of practical geophysics, as used in archaeology, forensics or in the explanation of volcanoes on television, is only a tiny part of the huge number of crucial applications this science has to all our lives.
As always with Dunedin guides, this is illustrated by full colour diagrams and a few photos, together with text that is simple enough to be read by non-specialists. This all means that it is an approachable and well-illustrated introduction to the many multi-disciplinary aspects of geophysics. And fortunately (at least from my point of view), Peter Styles has kept mathematics to an absolute bare minimum. There is also a glossary of the more technical terms used and a list of further reading.
Peter Styles is Professor Emeritus in Applied and Environmental Geophysics at Keele University and it was at that university that his interest in environmental geophysics developed. Although retired, he still does geophysics, mainly on contentious issues, such as induced earthquakes and subsidence caused by human activities, for example shale gas and other intrusive operations.
Introducing Geophysics, by Peter Styles, Dunedin Academic Press, Edinburgh (2021), 117 pages (paperback), ISBN: 978-1-7804608-0-2.