Lesson video

Hello, my name's Mrs. Harking.

Today's lesson title is "Living close to volcanoes," taken from the unit "Tectonic hazards: Why is Earth restless?" Today we're going to be exploring how and why people survive living on volcanoes.

Our outcome today is to explain why people live near volcanoes and how to prepare for and respond to eruptions.

There are a number of keywords that are useful to know before we start the lesson today.

If you're not sure about any of these and would like to write them down, please feel free to pause the video now.

Our first word is evacuate.

This means to move people away from an area that is threatened or hazardous to a place of safety.

Infrastructure.

This means all the basic systems in a country, such as transport and power supply.

It's what keeps a country running.

Short-term response.

This means the actions that occur in the hours, days, or weeks immediately after a disaster to help the basic needs of the people.

Long-term response, however, is actions that occur in the months or years after a disaster to help rebuild or recover.

So this is long-term actions versus short-term actions for a short-term response.

So this makes sense, doesn't it? Feel free to pause the video now if you need to.

Today's lesson is split into two parts.

First of all, "Why do people live near volcanoes?" Then secondly, "How can people reduce the risks?" First of all, "Why do people live near volcanoes?" Laura says, "Did you know that 1 in 20 people live close to an active volcano?" Izzy doesn't believe her.

"That can't be true.

Why would they do that? Volcanoes are pretty dangerous." Who do you believe? Is it Laura or Izzy? Laura is actually correct, it is true.

So 1 in 20 people live close to an active volcano.

That's quite a staggering fact, isn't it? 1 in 20 people.

Let's see if you can remember that fact.

Here's a quick check.

True or false? 1 in 100 people live close to active volcanoes.

Is this true or false? Yes, well done, it's false.

What was the correct facts? So I'll put this up here.

One in how many people live close to an active volcano? Yeah, well donne, it's 1 in 20.

So what's going on? Why do they live near volcanoes? What could possibly make them want to live there? Surely they're really dangerous.

We've got an example here, Mount Vesuvius, and this is a volcano in Italy surrounded by settlements.

So you can see where it is located on the European map on the left and on the right you can see Mount Vesuvius.

It is labelled in the centre of that satellite image, and surrounding it there's a lot of grey area, and these grey areas are all the settlements.

And you can see Naples as an example there, which is a very large settlement very close to Mount Vesuvius.

There is actually history here showing how dangerous it is to live there.

So Pompeii is a settlement which was destroyed by the eruption of Mount Vesuvius in 79 AD.

Yet it is now surrounded by settlements.

There's even a new Pompeii.

So this is quite a surprise, isn't it? If something has destroyed a whole settlement, and this particular example is extremely famous, surely people wouldn't want to build around there.

They would move away from the area, surely.

But that's not what's happened here.

Quick check time now.

True or false? Ever since Pompeii was destroyed by an eruption, people have avoided living near Mount Vesuvius.

Is this true or false? False, exactly.

There are many settlements around Mount Vesuvius, including a new Pompeii.

Pompeii was destroyed by pyroclastic flow, but there are other risks from living close to volcanoes too, such as ash and lahars.

So just as a quick reminder, pyroclastic flows are extremely hot flows involving volcanic gases, rock, and ash that flow very, very fast down at the side of a volcano, faster than you could outrun or out-drive.

You can see the ash here that has settled from the ash cloud that has erupted out of the volcano.

And then lastly, we've got the lahar.

So the lahar is a mixture of the volcanic deposits, for example, ash, but with water.

This might be for rainwater or melted glacial water.

And so it creates a muddy flow that flows down the side of the mountain, called a lahar.

Can you name one hazard caused by volcanoes? Well done, so you could have picked pyroclastic flows, ash or lahars.

But why would people want to live somewhere where there's all of these potential hazards? There must be something very attractive about these volcanoes.

And that's true.

There are many opportunities provided by volcanoes.

For example, fertile soils, tourist income, and geothermal energy.

We're going to look at these in a bit more detail.

So let's look at the fertile soils first.

So volcanic ashfall can kill crops after an eruption.

But long term, over the years, volcanic ash breaks down, adding nutrients to the soil.

This means the volcanic landscapes can be very fertile and ideal for crops.

So many volcanic slopes have farms on them.

And one example of a crop that really does well is the prized grapes grown on Mount Fuji in Japan.

There are other examples as well, such as the San Marzano tomatoes on Mount Vesuvius.

There's Andean potatoes which are particularly prized grown on the Andean Mountains where there are volcanoes over there.

So there are lots of different examples and I could go on and on listing different crops.

Volcanoes attract many tourists who hike up volcanoes, take pictures, relax in hot springs heated by underground volcanic activity, and you can see them here in this photograph.

So this is on Mount Irazu, which is in Costa Rica, but there are many other examples of volcanoes that are attracting tourists all the time.

This helps local businesses and economies such as tour guides, leisure centres, restaurants, hotels, all are making money from the tourists that visit, meaning that that provides jobs, and that can be really attractive and a reason for people to move to the area or remain living in the area.

Let's have a look at the geothermal reasons now.

Volcanic regions have hot rock closer to the surface than other areas.

This can be used to heat water and even create geothermal electricity.

This is how it works.

Water is pumped down into the rock.

The water is heated by the hot rock, which is closer to the surface here.

And then steam rises and turns a turbine, generating electricity.

An example of this is the Nesjavellir Geothermal Power Plant in Iceland.

Time for a quick check now.

Which of the following features of volcanoes support farming? Is it A, ash added to the soil; B tourist attractions; or C, geothermal energy? Well done, it's A, ash added to the soil.

Although just as a side note here, in some areas such as in Iceland, geothermal energy is used to heat greenhouses, so this could be corrected.

So they might grow, for example, tomatoes in a greenhouse because the air is too cold to grow these crops outside, and so the geothermal energy can be useful for farm.

Practise Task A now.

Firstly, could you create a table to assess whether living close to a volcano is a wise idea? In the left-hand column you're putting the benefits of living close to a volcano.

In the right-hand column you're putting the risks of living close to a volcano.

Maybe three things on each side would be a good idea? The second part of this task, would you want to live near a volcano? Why or why not? So you can use the information you've put in the table to help you think about what your opinion might be, and then I'd like you to make sure you're justifying that, you're saying why you think that.

Feel free to pause the video now to give yourself time to do this task.

Well done, everyone.

Let's have a look at your answers compared to mine.

Create a table to assess whether living close to a volcano is a wise idea.

My table looks like this.

Benefits of living close to a volcano include fertile soils, tourist income, and geothermal energy.

But the risks of living close to a volcano include deadly pyroclastic flows, ashfall smothers the crops, and lahars destroy infrastructure.

Did you get all of that? Would you like to add something now? Right, for task two.

Would you want to live near a volcano? Why or why not? So Sam has said, "I would want to live near a volcano as I believe the benefits outweigh the risks.

I could run an ecotourist resort powered by geothermal energy.

There might be hot springs that the guests and I could enjoy." Jacob says, "I would not want to live near a volcano as the risks from pyroclastic flows, lahars, and ash are too great.

Even if it meant I earned a lot of money, we need to learn from Pompeii." Which opinion did you agree with more? Was it Sam or Jacob? Is there anything you'd like to add to your own answer? We're now having a look at the second part of our lesson, "How can people reduce the risks?" There are three main ways that we can reduce the impacts that volcanoes have on the people that live in the area.

Firstly, there's preparation.

This is preparing before an eruption.

Here on our timeline, the eruption is shown by a star.

Then we have short-term response.

This is immediately after an eruption and it's the actions taken to try and reduce the impact of the eruption on people.

The long-term response is in the months and years following the eruption.

Let's take a look at each of these three stages in a bit more detail.

First of all, preparation.

Schools and local emergency services educate the community on what to do in case of an eruption.

They also run drills to prepare for eruptions.

Here's a poster that explains to people how they can prepare.

It says, "Be safe.

Make sure you keep an emergency kit with food, water, masks, and flashlights.

Sign up for volcano alerts from local authorities.

Stay indoors if there's ashfall and wear a mask to protect your lungs.

Know the fastest way to evacuate." So this is a really useful list for people who live on volcanoes, but actually we live in a world where people do travel a lot, so there's a chance that you might find yourself in a situation where you need to know this information as well, and actually thinking about signing up for volcano alerts from local authorities if you were travelling to an area with a volcano isn't the worst idea.

So worth taking a look at this list because you never know, one day it could save your life.

Local authorities create risk maps which may show zones which should be evacuated and the best routes to use.

These can be created in advance of volcanic eruption by predicting where flows will travel.

You can see here on the right that there's a road sign that shows a good evacuation route to take during a volcanic corruption.

The most dangerous zones are along river valleys where lava, pyroclastic flows, and lahars can flow easily during an eruption.

If you think about it, river valleys have already been eroded and have already been sought out as the route of least resistance by rivers, so they make sense as a route for lava flows, et cetera, to travel down because it is the route of least resistance.

Gravity is going to pull whatever it is that's flowing down the slope and they're going to take the easiest possible route.

You can see here on the right-hand side that it is easy to identify the zones where these risks are because we can look at the physical geography of the area.

You can see the Nisqually River here with a blue line, and then we've also got valleys shown by the contour lines as well.

These V-shaped contour lines show us the valleys, so these areas are the areas that are at most risk from the flows that occur during an eruption.

Quick check time now.

True or false? Highway 410 follows the White River that runs down the slopes of Mount Rainier.

This is a safe route for evacuation during an eruption.

Is that true or false? You're correct, it's false.

The lava, pyroclastic flows, and lahars tend to follow the river valleys on the slopes of a volcano.

Another way to prepare is to try and predict when an eruption might happen.

Seismometers are used to detect small earthquakes which could be caused by rising magma.

A change in the pattern of earthquakes could show that an eruption might be about to take place.

Monitoring to predict eruptions can allow time for evacuation of people from the areas that are most at risk.

Scientists can also measure the amount and type of gases coming from a volcano.

If there's a sudden change, it could mean an eruption is coming soon.

You can see in the image here this scientist is sampling the gases coming out of the volcano.

Thermal cameras are another way that scientists can try and predict when an eruption is going to happen.

Scientists identify areas where the surface layers of the volcano are getting hotter.

This could mean that the magma is rising.

These cameras are often remote, far away, for example, on satellites.

Time for a check for understanding.

Which statement is true? Is it A, volcanoes can only be monitored remotely, as visiting a volcano is too dangerous.

B, volcanoes can be monitored on the ground and remotely.

C, volcanoes can only be monitored by scientists on the volcano itself.

Well done, it's B.

Volcanoes can be monitored on the ground and remotely.

Not all eruptions can be predicted.

And though people can be evacuated, infrastructure itself can't move.

Therefore, the response to volcanic eruptions is extremely important.

We have short-term responses which are happening immediately after the eruption.

So local and international emergency services help rescue survivors and recover the victims. They also provide aid such as food, water, shelter, and medical supplies.

In the long term, there are long-term responses.

So this happens in the months and years after the eruption.

Infrastructure such as roads and buildings, as well as networks of pipes and wires, must be repaired in order for the area to recover.

These are preferably designed to be more resilient to future disasters in the process of repairing and replacing them.

Time for a check for understanding.

Which method to reduce the risk from volcanoes is missing from this timeline? Yes, short-term responses.

Another quick check.

Select an example of a long-term response.

Is it A, emergency services help rescue survivors and recover victims? Is it B, emergency services provide aid such as food, water, shelter, and medical supplies? Or is it C, infrastructure such as roads and buildings, as well as networks of pipes and wires, must be repaired? Good, it's C.

So that's the only one that happens a long time after the eruption rather than straight away.

Both A and B are immediate responses that happen straight away after an eruption.

Time for our Task B now.

Can you complete the timeline using the following words? We have rescue, rebuilding, educating, aid, infrastructure, and monitoring.

So our timeline looks like this.

First of all, there's preparation, and this involves.

The public as well as.

The volcano.

So that happens before an eruption.

Then the eruption occurs and we have short-term responses include.

And.

And in the months and years following the eruption, there is the long-term responses, which include the repairing or.

Of damaged.

Can you fill in the gaps now? Time for Task B now.

Can you advise the premier, which is similar to a prime minister, of Montserrat in the Caribbean, how should the island prepare for an eruption? You can see on the left-hand side here we have a map of Montserrat and it has the Silver Hills volcano, which is extinct, so there's no risk from that one, and that's in the northern part of the island.

In the southern part of the island, we've got the Soufriere Hills volcano, which is active and there's a high risk with this one.

So can you include in your answer, firstly, strategies to help people prepare, ideas about how to monitor volcanoes, as well as suggested evacuation zones.

So you can add an evacuation zone drawn onto a basic map of this island.

Please pause the video now to give yourself time to do the task.

Well done, everyone.

Let's have a look at your answers compared to mine.

First of all, we have the timeline.

So preparation involves educating the public as well as monitoring the volcano.

Short-term responses include rescue and aid.

Long-term responses include the repairing or rebuilding of damaged infrastructure.

Our second task was that advice to the premier.

So my example looks like this, I've got the map on the left-hand side with a suggested evacuation zone.

This is the evacuation zone that's actually in use in Montserrat at the moment.

On the right-hand side, we have a letter to the premier.

It says, "Dear Premier, I would recommend you educate the citizens of the island by advising them to keep an emergency kit, sign up for volcano alerts, stay indoors and wear a mask in the event of ashfall.

They also need to know the fastest way to evacuate.

An effective way to do this is to run drills.

It is also wise to monitor the volcano using seismometers, by sampling gases and the use of thermal cameras to predict future eruptions.

This information will inform you about when the area surrounding the Soufriere Hills volcano, the southern half of the island, should be evacuated." Well done, everyone.

We're now at the end of our lesson.

Here's our summary for today.

1 in 20 people lives close to an active volcano.

The benefits include fertile soils, tourist income, and geothermal energy.

There are also risks, including pyroclastic flows, ash, and lahars.

Preparation, including public education as well as the monitoring of earthquakes, reduce the risk to people living near volcanoes.

Decisions to evacuate people can be made in time.

Short-term responses to volcanic hazards include the provision of food, aid, and shelter to those affected.

Long-term responses include infrastructure repair or rebuild in the months and years after the eruption.

I hope you found today's lesson interesting.

I've certainly enjoyed learning with you.

Looking forward to seeing you next time, bye-bye.