Professor Bill McGuire answers questions on Geophysical Global Events (GGEs)
1. What are Geophysical Global Events (GGEs) and how are they categorised?
Global geophysical events (GGEs) are naturally occurring phenomena, but on a very large scale. Except within the contexts of scale and extent, the processes and mechanisms that underpin them, and their physical effects and consequences, are no different from the geophysical events - whether windstorm, flood, volcanic eruption, earthquake or tsunami – that trigger natural disasters many times every year. GGEs are low frequency - high consequence geophysical phenomena capable of having wholesale harmful ramifications for the environment and society.
2. How often do Geophysical Global Events occur?
Both the frequency and the size may vary according to the phenomenon under consideration. Broadly speaking, however, frequency ranges from hundreds of years to hundreds of millions of years and the size from local through regional to global.
3. What are the chances of the different types of events occurring?
While the probability of a GGE happening in any single year is below one per cent, and often far below this, all will happen in the longer term. The Earth will be struck by a large asteroid at some time in the future and a volcanic super-eruption will once again drape the planet in a sulphurous veil that blots out the sun for years – that is certain.
4. Have any Geophysical Global Events occurred in the past and if so, what evidence is there of them and the impacts they had?
GGEs have occurred throughout Earth history. Examples include the Toba super-eruption in Sumatra (Indonesia) around 74,000 years ago, which is charged by some with almost wiping out humanity, and others at Yellowstone (Wyoming, United States) 640,000 and 2.1 million years ago. Significant impact events have occurred at least twice in the last couple of million years. More recently, the 1923 Great Kanto earthquake that obliterated much of Tokyo, can be classified as a GGE as a consequence of its impact on Japanese society and the resulting political ramifications for the world in the run-up to Wold WarII.
5. Are there any future Geophysical Global Events that we should be particularly worried about?
Probably the most imminent is the next large earthquake to strike Tokyo. This has a high (around 30%) probability of happening in the next few decades, and could result in losses totalling one trillion US dollars or more. The impact of this on a weakened global economy could be devastating.
In relation to physical impacts, the future collapse of the western flank of the Cumbre Vieja volcano (La Palma, Canary Islands) is worrying, as it has the potential to generate a tsunami great enough to cause massive destruction around the margins of the Atlantic Basin. Such a collapse could be thousands of years off or perhaps not.
Another concern is the next major quake in the Cascadia Subduction Zone off the west coast of North America, which could be extremely destructive and have a major impact on the US (and therefore the world) economy.
6. Many Gee Gees are depicted in movies, such as mega- tsunamis or mega-earthquakes, can these events happen in real life and will the damage they cause be similar to the films?
Sometimes such films get things about right. I was consultant for the BBC drama, Supervolcano, so was able to ensure that the finished product was factually (almost) spot on. Some films do get things very wrong though. The worst was probably the US TV drama Megaquake, which envisaged California being struck by a magnitude 10 earthquake. As the size of a quake is related to the length of the rupturing fault this would be impossible. The fault would have to be far longer than any that exists on the planet.
7. If an event was to occur, what could be the impact on today’s natural and human environments over the short and long terms?
The adverse remote consequences of a GGE on our environments may range from disruptive to catastrophic and may arise:
- From a global physical effect, such as an episode of planetary cooling in response to a so-called volcanic super-eruption or large asteroid or comet impact
- Or as a result of secondary knock-on-effects for the global economy and social fabric due to a cataclysmic regional event, such as an Atlantic- or Pacific-wide mega-tsunami, or a more spatially-restricted event at a strategically-sensitive location, for example a major earthquake striking Japan’s Greater Tokyo Metropolitan Region
Depending on the scale and extent, the effects could last from years to several decades, or even longer for the largest events.
8. How are Gee Gees predicted and monitored by scientists?
GGEs are not yet effectively monitored or predicted. On the one hand, sky surveys are working hard to identify and track all large, potentially-threatening asteroids, but on the other we are only monitoring a few hundred of the planet’s 1,500 or more active and potentially active volcanoes. We still cannot predict earthquakes, however much monitoring instrumentation we put in place.
9. Can anything be done to prevent Geophysical Global Events taking place?
In most cases the simple answer is no. If we see it far enough in advance, however, we should be able to give an asteroid heading our way a nudge that would translate a certain hit into a near miss.
10. How can societies protect themselves from Gee Gees?
Contingency planning is the key. Even though they are rare, all national risk registers should have plans in place to cope with the aftermath of a GGE, including food, water and fuel rationing and means of maintaining transport, law and order and a functioning society. In the case of the UK, bearing in mind the chaos caused the 2010 Icelandic ash eruption, I am not optimistic that we will manage very well.
11. What work does the Aon Benfield UCL Hazard Research Centre (ABUHRC) carry out?
The ABUHRC is Europe’s leading multidisciplinary hazard research centre. It carries out curiosity-driven research into all natural hazards, most particularly volcanic eruptions, earthquakes, tsunamis, landslides and windstorms. It also explores the links between climate change and hazards and advises the insurance and other commercial sectors on the risks presented by natural hazards.
12. If I wanted a career involved in research into GGEs what should I do?
The first essential is a good degree in a physical science (for example mathematics physics, geology and geography) followed by either a specialist Masters (UCL has a Masters programme in Geophysical Hazards) or – better still – a PhD in the field of hazard or risk. An academic research career would then be best in order to provide the time and freedom to study the GGE of your choice.
Bill was interviewed in January 2011.
Prof Bill McGuire’s biography
Bill McGuire is Professor of Geophysical and Climate Hazards at University College London and Director of the university's Aon Benfield UCL Hazard Research Centre - Europe's largest, multidisciplinary academic hazard research centre. A volcanologist by inclination and training, he has worked on volcanoes all over the world, and published over three hundred papers, books and articles on volcanoes and other natural hazards.
Read Bill’s full biography.