Earthquakes and Volcanoes

LINKS

Interactive volcano and earthquake mapping:
https://www.pbslearningmedia.org/resource/buac17-68-sci-ess-quakevolint/earthquakes-and-volcanoes-interactive/

Build your own seismograph:
https://www.scientificamerican.com/article/shaky-science-build-a-seismograph/

EPISODE TRANSCRIPT

Animals know about them before we do… school kids in the ring of fire practice for them… and they are very tricky to predict. This is your Squiz Kids Shortcut to Earthquakes and Volcanoes—the podcast where we dive into the who, what, when, where, why and how of the big news stories. I’m Amanda Bower.

And I’m Bryce Corbett.

This week, earthquakes struck both Indonesia and the Solomon Islands… and in 2021, the people of Melbourne got knocked around by one as well.

Today, we’ll take you through WHAT volcanoes and earthquakes have in common, WHERE they usually happen, and HOW people living in those places adapt.

Listen carefully – there’s a S’quiz at the end!

WHAT
Amanda, I’m having a hard time imagining what these two things have in common. Volcanoes are all about liquid hot rock spewing out of a big mountain, and earthquakes make the ground shake and move under our feet. They sound pretty different to me.

Well, on the very simplest level, they are both geological events. Geology is the study of the structure of the earth, and earthquakes and volcanoes are both caused by movement of the massive rock structures that make up the Earth’s shell.

Are they the things called tectonic plates?

Aha, it’s all coming back to you! That’s right. The shell of the earth isn’t like the shell of an egg, with one smooth, uninterrupted outer layer. It’s more like… imagine boiling the egg, and then rolling it under the palm of your hand.

Cracks would appear everywhere, right?

Exactly. So the earth’s crust has these different plates, or chunks of thick rock. But instead of yummy boiled egg beneath, there’s the boiling hot core of the earth. That heat at the centre of the earth produces heat currents, and they cause the earth’s plates to move.
Wait… so I’m moving right now while I’m on Australia’s tectonic plate?

Yep! It’s called the Indo Australian plate, and don’t worry, it’s moving really, really slowly. The speeds have varied over earth’s history, but right now we’re not going any faster than 7 centimetres a year. That’s about the diameter of a tennis ball… over a whole year.

Oh, that’s REALLY slow. But wait – if it’s that slow, how can it cause something as massive as a volcano or an earthquake?

Well, with earthquakes, as the plates move, they get stuck in places, and enormous amounts of energy build up as they push and push. When they finally get unstuck and move past each other, waves of energy are released and cause earthquakes.

And is it the same for volcanoes?

No… almost 90% of all volcanic eruptions occur when the two plates have spread APART from each other. Most of the world’s 1500 potentially active volcanoes are found around the edges of tectonic plates, both on land and in the oceans.

Hmmm… 1500 potentially active volcanoes… WHERE are they all?

WHERE

Bryce, you sound a little anxious about those volcanoes, so let me set your mind at rest. The only potentially active volcanoes on Australian territory are in the Australian Antarctic Territory.

Phew!

Most of them are around what’s known as the “ring of fire”. I don’t want to give too much about the ring of fire away, because your first classroom resource is a really cool mapping activity. You’ll have a map of the earth, and a list of the major volcanoes and past earthquakes. You’ll map them onto the grid, and see what patterns you notice. And, if you don’t have time in class to do that, there’s a link to an interactive way to see this in your episode notes.

Well, we don’t want spoilers… but is Vesuvius, the Italian volcano that famously buried and preserved the town of Pompeii in the first century, part of that ring of fire?

Actually, no. Most of the world’s active volcanoes ARE in the ring of fire, but Vesuvius is the volcano that many experts consider the most dangerous, and it’s NOT near all those others. Its last deadly eruption was in the 1600s, and part of the reason it’s considered so dangerous is that six million people live close by.

What about La Palma, the Spanish island that erupted for weeks in 2021, sending chunks of lava the size of three story buildings into the air?

You’re killing me! No, that one is off the coast of Africa. It was a real doozy… it erupted for months, and destroyed more than 1,000 homes and buildings. The lava that came out of it was more than 1000 degrees, and the ash that’s rose up from the eruption went more than 3 km into the air – so no planes could go anywhere near it. But I promise you, 90% of all earthquakes, and three quarters of all volcanoes, are around the Ring of Fire.

But let me guess.. Melbourne isn’t on the ring of fire either, even though they had an earthquake in 2021.

Sigh. No, Melbourne isn’t on the ring of fire. BUT: New Zealand is, and experts think that pressure on those tectonic plates in New Zealand is actually what caused the quake in Melbourne. And even though it was a reasonably strong earthquake, it happened deep below the surface of the earth, so the damage wasn’t too bad. Your second classroom activity is going to be all about exploring and understanding the Gutenberg-Richter scale – which measures the strength of earthquakes. Now, most people call it the Richter scale…. Jump in to find out how Professor Gutenberg got a bit ripped off, and read about some of the biggest earthquakes the world has ever seen.

Amanda, I’m thinking about how you used to live in an earthquake hotspot… HOW do people who live in the Ring of Fire adapt?

HOW

That’s right, Bryce, I spent 14 years in the Ring of Fire, in San Francisco. It’s a serious earthquake zone. When I was a journalist at Time Magazine, my office building was more than 20 stories high, and it was built basically on roller skates… so when an earthquake happened, the building glided around, rather than crumbling down.

No way! Did you ever feel an earthquake?

Actually, all the time. Little earthquakes are happening constantly. After a while, you get used to readjusting the pictures on the walls! But there are lots of things you have to do to live safely in an earthquake zone. For example, you would never hang a heavy picture over your bed, in case it fell off on you while you were sleeping. The furniture is all anchored to the wall, so it won’t fall down. Houses are made with wood frames, not bricks, because wood is more flexible when the earth shakes. And everybody keeps an emergency kit with enough supplies to survive for a few days.

Did you practice what to do in earthquakes?

Absolutely! When I became a teacher, we had a drill every month. It was called “drop, cover, and hold”. You’d drop under your desk, cover your head, and hold onto the desk legs. Kids living in volcano-prone places do the same thing, and they keep emergency kits as well. The biggest difference is that they keep masks in those kits, because if a volcano does erupt, they don’t want to breathe in the ash. And… volcanoes are a bit easier to predict, so they often have a better chance of evacuating before it happens, like in La Palma.

But earthquakes are harder to predict, yes?

That’s right. Animals can feel them coming before humans can, because they pick up on the waves of energy before we do. We all know they’re smarter than us. You can also sign up to “shake alerts” on your phone, so when the government monitoring picks up an earthquake, you can get a few seconds warning. That doesn’t sound like much, but it does mean that you could turn off machinery, stop a car if you’re driving, and put power stations and other important things like that into safety mode.

Hmmm… I still think I’m pretty happy to live away from the Ring of Fire.

This is the part of the podcast where you get to test how well you’ve been listening…
Question 1. What’s the name of the earthquake drill that school kids practice in San Francisco? (Drop, cover, hold)
Question 2. What’s the name of the volcano in Italy that is considered the most dangerous in the world? (Vesuvius)
Question 3. What is the name for the area that contains most of the Earth’s volcanoes and earthquakes? (Ring of Fire)

That’s all we have time for today. Thanks for joining us as we explored the who, what, how, where, when, and why of earthquakes and volcanoes. Now get out there, and have a most excellent day! Over and out.