WHY DO EARTHQUAKES HAPPEN?
I THINK we all agree the world we live in is an incredible place. But, sometimes, the Earth can also be a scary place when disaster strikes. Last week’s deadly earthquake in Turkey and Syria is a reminder of that.
Earthquakes can cause the ground beneath our feet to shake and open up large cracks in the Earth’s surface. They happen somewhere in the world every day. But, unlike the devastating earthquake in the news this week, most of them don’t cause any damage.
In the UK, earthquakes are usually so small that you might not even realise they’ve happened.
Our partner Sky TV children’s news show, FYI, spoke to Dr David Hawthorn from the British Geological Survey to find out why earthquakes happen.
So what causes earthquakes?
David: It’s all to do with what we call plate tectonics. So, you might feel that the ground underneath your feet is a very stable place but, actually, it’s composed of these tectonic plates. You can think of the surface of the Earth like a giant spherical jigsaw puzzle. But these plates don’t just stay where they are – they’re actually moving around and that’s where the problem comes from. When those plates crash into each other, when they slide past each other, we get huge releases of energy. That energy gets released along fault lines and we feel that energy as earthquakes.
So most of the earthquakes happen along the fault lines?
David: Yes that’s right – most earthquakes do happen along fault lines because that’s where all the energy is being released. So it’s places like Japan, where one plate is being pushed under another, or places like America where you’re also getting lots of earthquakes.
That must be quite scary if you live in those places.
David: Yep, it’s definitely scary, particularly the first time you’re ever in an earthquake. But, for lots of countries that have really
big, dangerous earthquakes, they’ve got really clever about dealing with them. So, they have fantastically designed buildings that can withstand earthquakes. And, even children who are in school will be trained and drilled on a regular basis to make sure that they’re as safe as possible when there is an earthquake.
But they can still be really dangerous.
David: Yes they can… there’s no getting away from that. You’ve probably seen in the news people talking about the Richter scale [right] and how damaging an earthquake is. Well, the Richter scale’s a way of measuring what we call the magnitude of an earthquake. The biggest ever earthquake had a magnitude of 9.5 and that happened in Chile in South America. The biggest earthquake we’ve ever had here in Britain was a magnitude of 6.1 and that happened in the North Sea more than 100 years ago. Now, you might not think that there’s that much difference between a 6.1 and a 9.5. But, actually, a 9.5 magnitude earthquake is more than 100,000 times more energetic, more strong, than a 6.1 earthquake, which is one of the reasons why it didn’t do huge amounts of damage when it happened here.