An aerial view of Ishinomaki, Japan, a week after a 9.0 magnitude earthquake and subsequent tsunami devastated the area. Showing flooding, damaged buildings and roads.
Ishinomaki, Japan, after a tsunami devastated the area

A new viewpoint

This week we will start to look at events from a new viewpoint.

In Weeks 1 and 2 we were keen to stress the importance of looking at events over cosmological and geological timescales. A lot of the events we looked at occurred before humans were around to witness them.

Events from a human perspective

We’re now going to think about events from a human perspective.

Thinking back to the beginning of our course, we looked at the eruption that occurred at Mount Etna, Italy in 2017. We discounted it as an extreme event because it was neither rare nor large.

But it demonstrates how the types of events we’ve looked at so far can pose risks to us humans and our society. It also show how events can appear extreme relative to human experience.

Extreme events in the future

At the end of Week 2 we asked you:

Of the events we explored which one do you think has the greatest potential to shape and impact our planet in the future?

Well, given what we’ve seen, the probability of experiencing a supereruption or large igneous province is very small as we said that:

  • Supereruptions occur roughly once every 100,000 years
  • Large igneous provinces only occur roughly once every 10 million years

We also said that megatsunamis and megafloods are mainly caused by chance one-off events and aren’t events that have occurred regularly over the course of human history.

Megaquakes were the one exception as they happen much more frequently than the other extreme events we’ve looked at. They occur roughly once a year.

We know by now that all of these events are of a magnitude that can result in big changes to our planet. They are however very rare or in some cases extremely rare. This limits the potential for them to shape our planet in the near future.

Human understanding of events

This week we will see how preparations are made for potential future events based on the hazard and risks they present to us humans.

Our understanding of the events we’ve looked at is arguably much more developed than ever before.

It has evolved from eye-witness accounts to sophisticated modern day methods of measuring, evaluating and monitoring.

We’ll begin Week 3 by considering how human experience and understanding of extreme geological events has developed over time.


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Extreme Geological Events

Cardiff University

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