Nova (1974–…): Season 45, Episode 11 - Volcano on the Brink - full transcript
Explore Nyamuragira, one of the world's most active and mysterious volcanoes in Africa. Decades of civil strife have prevented scientists from investigating the volcano, but a brief pause allows an international team of experts to fly by helicopter to the summit to investigate.
In the heart of Africa
are two of the world's
most dangerous volcanos.
Within their craters,
molten lava steams and boils.
Over centuries
these volcanoes have erupted
many times,
but when will they erupt again?
It's a crucial question,
and no one knows the answer
because these are among
the least-studied volcanoes
in the world.
Now an international team
of scientists
has come to investigate
these giants,
to predict future eruptions
and save lives.
Everything we do to understand
this volcano is very important
to avoid another disaster.
Today,
they're flying
to a volcano called Nyamuragira
in a region rife
with dangerous militias.
After many active years,
this volcano
has stopped erupting.
The fire in its crater
appears to be gone.
We need to collect some really
critical data up there
to understand
what might happen in the future.
Will Nyamuragira erupt again?
And if so, when?
The people who live here
are at risk.
Can scientists find a way
to protect them
before time runs out?
Right now,
I just want to get things set up
and going,
so we can just get
as much as possible
in this really short time
that we have here.
Can they solve the mystery
of "Volcano on the Brink"?
Right now, on "NOVA."
Major funding for "NOVA"
is provided by the following:
In a remote region
of central Africa
lies one of the most active
yet least explored volcanoes
on the planet:
Nyamuragira,
as spectacular
as it is mysterious.
The volcano sits
on the eastern border
of the Democratic Republic
of Congo, the DRC,
near the shores
of the vast Lake Kivu.
Fewer than 20 miles
from the volcano
is the town of Sake.
Its residents
are all too familiar
with the threat
of its frequent eruptions.
Market traders Terese Kalume
and Mama Noya
have spent their entire lives
here
and witnessed the effects
for themselves.
Nyamuragira eruptions blanket
large areas of farmland
in scalding-hot, choking ash,
destroying crops,
killing livestock,
and bringing famine.
At the moment,
there is just such a break.
It's been five years
since the last major eruption.
Has the volcano gone extinct,
or will it erupt again,
more deadly than before?
It's this question
that an international group
of scientists
has come to investigate.
To do that, they have to be
transported to the volcano
by a United Nations
peacekeeping team.
For British geologist
Chris Jackson,
it's a field trip like no other.
It's actually
in a fairly dangerous
part of the the area,
so the only way to get there is
with a military helicopter.
My heart's racing
just at the thought
of getting on that helicopter.
Few people have visited
Nyamuragira...
For good reason.
This region of the DRC
was the center
of one of the bloodiest wars
of modern times.
Fueled by
a long colonial history,
vast mineral wealth,
political tensions,
and international pressures,
millions were killed
and injured.
Although the war
is officially over,
widespread unrest continues.
Violent militia and rebel groups
are operating in nearby forests,
so the helicopter flies fast
at treetop level
to stay out of their gunsights.
Even at this speed,
the helicopter provides
a great vantage point
to see one
of the most volcanic places
on earth.
American volcanologist
Kayla lacovino
has studied volcanoes
across the planet,
but the volcanism here
is on a scale
she's never experienced.
I thought I knew
what this landscape
was going to look like,
but there's really
way more volcanoes,
way more melt here
than I expected.
It's... the amount of
magma production in this region
is insane.
As they reach Nyamuragira,
they can see
it's a giant shield volcano,
so called
because successive lava flows
have spread widely
across the landscape,
giving its surface
a sloping, shield-like shape.
The volcano rises
to over 10,000 feet,
surrounded by old lava flows
that blanket
almost 600 square miles.
At the summit,
the main caldera created
by previous eruptions
is over a mile across,
with 300-foot-high walls
and, at its center,
a 600-foot-deep crater.
Usually such an active volcano
near so many people
would be covered
in monitoring equipment,
but because it's remote
and dangerous,
Nyamuragira has none.
This is a rare opportunity
to gather data
for predicting future eruptions.
We're hoping to land
on top of the volcano,
right next to its active crater.
We need to collect some
really critical data up there
to understand what might happen
in the future.
This is one of Africa's
most active volcanoes,
and it has
a very complex history.
During the past 100 years,
it's erupted from its flanks
at least 30 times,
flooding the surrounding
farmland in molten rock,
though this hasn't happened
for the past five years.
In 2014,
for the first time
in almost a century,
a small lava lake developed
in the center of the crater.
So, the first thing
the scientists want to check
is whether that lava lake
is still there.
We're banking round now.
There's just sheer cliffs
right down to the lava lake,
which,
from what I can see
at the moment, seems to...
seems to be crystallized,
so seems to have turned
into rock.
But does this
have anything to do
with the volcano's behavior?
With the lava lake
apparently gone,
will the volcano return
to its cycle
of huge, destructive eruptions?
Belgian geologist Benoît Smets,
who works with local scientists,
specializes in geo-hazards.
I think we should first follow
the, the cracks...
Okay.
And then turn right right, try
to avoid them. Okay, cool.
He discusses plans
with Aldo Kane,
a former Royal Marine,
who's in charge
of the expedition's safety.
Across the caldera,
this is where the gas escapes,
so it's quite dangerous.
Okay, all right, we'll
get everyone out,
and then we'll get
a bit of a brief then.
Okay.
It's not just the volcano
that worries Aldo.
Just to be aware
there are armed groups
operating in and around
the, the slopes of the volcano.
If you do see someone
that's not from our group,
then get on the radio,
let me know.
There is a path and tracks
going through here,
so they are using it,
it is accessible to them,
so keep your eyes peeled.
Any armed groups
that saw them fly in
could be heading to the summit,
so they can't stay long.
So, we've got two hours,
so we need to be back here,
everyone at the chopper
ready to go in two hours.
- Cool?
- Okay, sounds good.
Thanks, Aldo.
The urgent question for the team
is whether the current break
in large-scale eruptions
is coming to an end.
Kayla believes that the plume of
gases released by the volcano
will yield vital clues.
I want to find a place
where I can actually get
inside the plume
and put the gas box,
and that can tell me more
about the different chemicals
that are coming out
of the plume.
Monitoring the changes
in that gas chemistry
is what tells us whether
the system is changing,
whether it's moving
towards an eruption,
whether there's new, new magma
being input at the very base.
The gases really tell
the whole story.
Most volcanoes have
a magma chamber,
a reservoir of molten rock
deep underground
that fuels eruptions.
As the magma rises up
towards the surface,
it releases a mixture of gases.
A sudden increase in one gas,
called sulfur dioxide,
often signifies
an imminent eruption.
Kayla wants to discover the
concentration of sulfur dioxide
in the gas plume, but
it won't be easy.
I'm really...
yeah, I feel, I feel like
we're really pushed for time
here.
There is a lot of gas
coming out of here.
The problem for me is that
once it gets to the top,
it's, it's become
pretty diffuse,
which is why I'm having
to chase the plume around.
The team also needs to check
on activity
in the lava lake.
Kasereka Mahinda,
a geophysicist,
knows the summit
better than anyone
and can identify the best place
to see into the crater.
The best place to...
The best place is there,
because one time I stayed there,
you can see around the crater.
- Okay.
- Yeah.
Most eruptions are driven
by a build-up of pressure
inside a volcano.
It's possible that the lava lake
that appeared in 2014
acted like a safety valve,
an open vent releasing pressure.
When Kasereka was last here,
the lava lake was still active,
a small cone erupting
in its center.
I was here,
you have active lava
in the crater,
very big, active lava.
But now, from the helicopter,
it looks as though
the lava lake
is no longer active.
If so, then the volcano
may have lost its safety valve
and could now be building
towards a major eruption.
With only two hours to try
and find out what's happening,
the team decides to split up.
Kayla heads off on her own
to get a gas sample,
while Kasereka leads the others
to the vantage point
overlooking the crater.
Kasereka works
at the Goma Volcano Observatory,
which carries out research
on volcanoes across the region.
The observatory's job
is not only to monitor
the risk of eruptions
but also the long-term effects
of living in such
a volcanically active area.
We look at the whole landscape,
you know, it's about...
they... all volcanoes
in the landscape, that's one.
But mainly we focus
on the two active volcanoes.
Still... we still also
monitoring the rest.
We do also measure the quality
of water people are drinking
to advise
the health authorities.
Mathieu Yalire
studies volcanic gases.
Together with fellow
volcanologist Dario Tedesco,
he's investigating
the volcano's effect
on the water supply in Sake.
This is part of our
job, to analyze water,
all samples we can get
around the region.
Volcanoes tap the inner earth,
releasing certain elements
into the environment
in much higher levels
than normal.
Some can be harmful.
Mathieu and Dario are interested
in one particular element:
fluorine, that dissolves
in water to form fluoride.
Many of the townspeople
have brown, stained teeth.
Not a sign of neglect
but possibly a condition
known as fluorosis,
too much fluoride in their diet.
Around the world
sodium fluoride is often added
to drinking water.
At low concentrations,
it helps prevent cavities,
but at higher levels,
it can cause problems.
Mathieu and Dario measure
the levels of fluoride.
The limit of this machine
is ten part per million,
and it says, "Over the limit."
The water has levels of fluoride
around ten times
the recommended safe limits...
Concentrations
that can damage teeth,
bones, joints,
and even organ function.
And there is no easy remedy.
At present, we really don't have
any solution,
because the best solution
would be to bring water
from very far from here,
in, uh...
Masisi.
Masisi, Masisi area.
It's a very... It's
20, 30 kilometers.
This is not only this village.
It's more or less
100,000 people or more
that live in the area.
There's another effect
of the elements thrown out
by the volcano,
one that benefits the community.
Between eruptions,
the lava and ash break down,
releasing nutrients
into the soil
and creating incredibly rich
and productive farmland.
It's why the market
is full of food.
For local people,
this combination
of risks and benefits
can lead to a complex mindset
of both fear and appreciation
of the volcano.
Back on Nyamuragira,
the scientists are trying
to figure out
what the volcano will do next.
Kasereka Mahinda
from the Goma Observatory
is leading them to a viewpoint
over the crater
to help them assess
if the lava lake
that formed in 2014
is still active.
Oh, wow.
As you walk towards the edges
of these craters,
you get that feeling
in your stomach,
like you're about to go off
the edge of the world.
The crater is dark.
It looks as though
the activity Kasereka observed
in the lava lake
has now stopped.
To be sure,
Benoît and his colleagues
set up a thermal camera
to check
if there's any magma moving
beneath the thin crust
of black rock.
But that means getting
uncomfortably close to the edge.
Just go careful on that edge,
this entire edge,
even under where
your camera is there,
is over-hanging.
That's millions of tonnes
of rock there,
and they're right
on the edge of it.
They check the temperature.
Intense heat would mean
the vent is still active.
So what's the temperature
down on the base?
So everything has
the quite same temperature,
about 45 to 50 degrees Celsius.
Although quite hot,
50 degrees Celsius,
or 120 degrees Fahrenheit,
is not hot enough
for there to be magma
near the surface.
It's totally dead.
No activity left at all.
And the question is now,
is it just a break
or is it just finished?
It means that
the activity may change.
With no active lava
and a solidified crater floor,
pressure could be building
inside the volcano.
The volcanic activity
that we see
is only a very very small part
of the real volcanic activity.
There is much more happening
below the surface.
Some of the best clues
of what's happening
beneath the surface
are the gases given off
by the volcano.
They could reveal
if new lava is rising up inside,
threatening an eruption.
That makes
Kayla's gas measurements
all the more important.
But getting a sample
is proving difficult.
Unfortunately, the best place
where the gas is coming up
is also on, I think,
the most precarious part
of the entire crater rim.
It's why I'm not over there,
where its gassiest.
Is that... these thick
layers of ash,
that looks like
the most unstable,
but I'm just trying to get
as close as I can
without being unsafe.
Given the dangers
of gathering data,
Kasereka sets up
a simple instrument
he knows will be helpful
in understanding the volcano.
I need to set up my...
You're setting up here?
Yeah?
The observatory is trying
to establish a set
of baseline measurements
to spot changes in the volcano
that could signal an eruption.
So what are you gonna
set up here?
I set up the thermometer
to measure the temperature.
So, temperature measurements?
Yes.
Kasereka's focus
is the fumaroles
found across the crater,
cracks and openings
that can reach all the way down
to the magma chamber.
Measuring their temperature
can reveal what's happening
deep inside the volcano.
You know, we'll see if there,
the temperature increase or not.
Okay.
So I can tell if the magma
is coming up or not.
As magma moves up
inside the volcano
before an eruption,
the fumarole temperature
increases dramatically.
But to spot that,
a set of baseline measurements
is essential.
We've lowered the probe in
about a meter, meter and a half.
Yeah, this one will record
every five minutes;
Okay.
I try to reduce the minutes
because we don't have
enough time.
There's no screen
on the data logger,
so we can't see what the
temperatures are at the moment.
We have to wait
till we go back and plug it in.
Yeah, I have to go back
to my office,
Okay... okay.
'cause I have some software
to analyze, yeah.
This kind of data
could ultimately help
predict future eruptions.
With little time remaining,
Benoît is also determined
to squeeze in
one last experiment
that could reveal pressure
building within the volcano.
I would like you to follow
the drone with binoculars
to be sure I don't crash it.
Years of observations
around the world
have shown that
before an eruption,
increasing pressure can change
the shape of a volcano,
making it swell.
Perhaps the most extreme example
is Mount St. Helen's
in Washington state.
In 1980,
the north side of the volcano
bulged outwards some 270 feet
just a month
before its violent eruption.
Usually scientists are looking
for much more subtle changes,
which can take months
of monitoring
with a whole range
of ground-based sensors.
That's not possible here,
so Benoît has come up
with a high-tech solution.
I'm using a drone to take
pictures of the big crater
in different viewpoints.
And with this set of images,
I will be able to create
a 3D model of the big crater.
The computer model
Benoît creates
is a 3D snapshot of what
the crater looks like today.
Comparing it to images captured
on future visits
will allow him to spot
small changes in the terrain,
which may precede
an impending eruption.
Benoît has just enough time
to finish his survey.
The two hours are up,
and weather is closing in.
We are a long way
from the helicopter,
and there's a huge bank of cloud
that's coming our way,
so I think we take
the weather window
and we bug out.
If the storm hits,
the helicopter will not be able
to take off,
leaving the team stranded
on the summit.
If you need me to carry
anything, let me know.
Okay. There's some
space in my pack.
And we still need
to pick Kayla up
on the way as well,
'cause she's still
over there doing her gas box.
It's been a frustrating day
for Kayla,
who hasn't managed to capture
any useful data.
It's just so hard to work
in places like this,
where access
is nearly impossible,
and then when you get access,
you have two hours.
It's just not enough.
Even so,
this rare visit
has been worthwhile.
They've confirmed that the
lava lake that appeared in 2014
is no longer active,
raising the possibility
that the volcano may once again
be building
towards a major eruption.
If so,
the new monitoring equipment
they've left behind
may help forecast that event.
As the team departs,
they turn their attention
to another goal
of their expedition:
investigating what makes
this part of Africa...
so intensely volcanic.
It's amazing from up here,
the view you get.
From the ground,
it was spectacular,
but from here,
it is absolutely something else.
This is flat land
with these volcanoes
just punching through
absolutely everywhere.
The entire area is filled with
evidence of volcanic activity.
Each one of these small hills
is an extinct volcanic cone.
But what is the impact
of living
in such a volcanic landscape?
To find out,
the team travels to Goma,
a city of almost
a million people
that lies south of Nyamuragira
and another giant
volcano, Nyiragongo.
Nyiragongo last erupted in 2002,
sending rivers of lava
into the heart of Goma,
causing death and destruction.
The city has since recovered
and is growing.
Today Chris and Aldo are heading
to a local boxing gym.
Wow, check this out.
They're here to learn
about the relationship
between the area's
volcanic history,
its ongoing instability,
and what local people are doing
to address the trauma
of violence.
Continuing unrest here
means that children
often have little choice
but to fight in the armed gangs
and militias
that operate around Goma.
Some of the men in this gym
were once child soldiers.
The discipline of boxing
provides a way for them
to escape their violent past.
The continuing unrest
and use of child soldiers
are driven by the extraordinary
mineral wealth of the region,
especially one mineral
that plays a crucial role
in modern life.
This is the mineral coltan,
this dark-colored mineral here.
It's the kind of mineral
I'd expect to find
in an area like this.
And any touchscreen phone,
laptop,
anything with a transistor
will have tantalum,
which is the tan of the coltan.
The explosion in smartphones
and other electronics
means coltan is
in constant demand.
Even small mines
can generate huge profits,
but in this region,
militias control
many of the mines.
The income means
they can recruit young people,
fueling the ongoing violence.
It's very hard to hold this
in your hand,
knowing how much we desire it,
and knowing
what it leaves behind
and where it comes from.
Bonjour, Kibo.
The head of the gym, Kibomango,
is a former child soldier
who now tries
to help young people
rebuild their lives.
And you're happy for us to join
in some, some training?
Joining, joining,
no problem, no problem, yes.
Aldo's fascinated
by Kibomango's story,
because like him, Aldo became
a soldier at an early age.
So, Kibo,
when did you join the army?
Which is two years younger
than I was when I joined up.
How long did you serve
in the, uh, in the army?
Although Aldo joined
the Royal Marines at 16,
legally he couldn't see
frontline action
until he was 18,
unlike Kibomango
and the young people here.
I wouldn't mind betting that
what Kibomango's doing here
to run this boxing club
is partly for his own therapy.
As a child soldier,
he's going to have seen
some pretty nasty stuff.
After the workout,
Aldo has a chance to take on
the man himself.
Kibomango is
a former Congolese champion.
In a poor and job-starved area,
militias are one
of the few sources
of money and employment.
It's a vicious cycle.
The chaos in the region
helps gangs control
the mineral wealth,
and in turn the mineral wealth
allows the gangs
to maintain the chaos.
There are efforts underway
to break the cycle
by promoting a more sustainable
use of the resources
created by the volcanoes.
They focus on
the Virunga National Park,
a vast nature reserve covering
around 3,000 square miles.
Its fertile volcanic soils
make it one of the
most diverse parks on the planet
and one of the few places
where it's still possible
to see mountain gorillas.
These highly social animals
thrive in this lush
forest habitat,
eating mainly leaves, shoots,
and stems.
Thousands of people come to see
the gorillas,
generating cash that's used
to create local jobs.
But following attacks
by poachers and criminal gangs,
the park had to close
temporarily,
another setback for a region
where volcanic riches
have the potential
to create
a very different future.
But what makes this area
so volcanically active
in the first place?
It's a question the scientists
are determined to answer.
From the helicopter,
I got a, like, almost
a once-in-a-lifetime view
of the entire
volcanic landscape.
And what really struck me
was the amount of volcanism
and the amount
of volcanoes here.
We have hundreds
and hundreds of them.
This extraordinary concentration
of volcanic activity
is related to a vast chain
of mountains and valleys.
The East African Rift.
It's a massive
geological feature...
stretching nearly 4,000 miles
up the eastern side
of the continent,
and the Goma volcanoes are
at the midpoint of the rift.
The earth's outer crust
is divided into giant slabs
called tectonic plates.
Along the East African Rift,
the tectonic plate is splitting,
and the two sides of the rift
are moving away from each other
as the continent
slowly rips apart.
If the split continues
over millions of years,
a new ocean
and continent will form.
But many rifts
don't fully develop.
The waters of the Mississippi
now fill the scar left
by a failed rift
when a huge section
of what's now the Midwest
started to tear apart
around a billion years ago...
And then stopped.
Will the East African Rift
also fail?
The answer hinges
on a controversial theory.
So, one thing it could be
is something called
a mantle plume,
that's a column
of deep, hot material,
which is rising up
towards the earth's surface.
As it comes
to the earth's surface,
it can weaken the plate,
and it can actually
force the plates apart,
but some of that melts,
some of that magma
can also come out
onto the earth's surface
and build volcanoes.
The earth's mantle lies
between its dense core
and its thin crust.
The presence of a mantle plume,
a huge column of heat
and melted rock
rising from deep
beneath the region,
would explain why there
are so many volcanoes here.
If a plume exists,
then the enormous heat
and energy it brings
could keep the rift active
long enough
to split Africa apart.
Like all geological theories,
we really need to go out
into the landscape
and look
for additional evidence.
So along with Kayla,
Chris goes on the hunt
for evidence of
a distinctively deep upwelling
of heat and magma,
the signature of a mantle plume.
The first place
they want to look
is one of the extinct
volcanic cones,
common in the region.
I'm really interested to see
some of the smaller cones,
because we've been looking
at Nyiragongo, Nyamuragira,
you know, the big boys.
There's so much information that
the smaller cones can have too.
Their destination is Lac Vert,
the "Green Lake,"
just outside Goma.
Wow, look at that.
Today it's a 300-foot climb down
from the crater rim to the lake.
People bathe
and wash clothes here,
but around 500 years ago,
this was an active volcano.
Chris and Kayla want to know
what sort of eruption
formed Lac Vert,
and whether it could be linked
to the presence
of a mantle plume.
They also want to find out if
this volcano could erupt again,
and what that would mean
for the city of Goma.
They start
by examining the rocks
that make up the volcanic cone.
For many years
the sides have been quarried,
so with a little effort...
You got to go over the head.
Over the head?
Yeah.
It's easy to get their hands
on some samples.
None of this is actually lava,
this is all ash,
these are all ash deposits.
And that means this was magma
that came up through the ground,
was exploded onto the surface
and absolutely ripped apart
into very, very fine pieces
that you can see here.
Imagine how much energy
it would take
to take solid rock,
and, and just explode it
into these tiny, tiny bits.
That screams to me that
there was an interaction
with the water
when this actually erupted.
Goma sits in the middle
of a string of craters
like Lac Vert,
each formed
by explosive eruptions,
and each capable of delivering
a devastating blast.
The eruptions are caused
by magma welling up
from underground.
When the magma hits a layer
saturated with water,
the extreme heat instantly
turns the water to steam,
triggering a powerful explosion.
This generates huge amounts
of fine-grained ash,
just like the deposits
found here...
Clear evidence that Lac Vert
was formed by this type
of explosive eruption.
The sides of the crater
also reveal something else:
this wasn't a single event.
What strikes me,
as somebody who's interested
in sedimentology,
is how many layers of rock
there are like this.
The layering
in the rock behind us,
I wouldn't want to go over there
and count them,
but there's clearly hundreds
and hundreds
of giant explosions
associated with
this catastrophic eruption.
It may be about five centuries
since the last eruption,
but the danger of a new one
is very real.
We've still got lots
of volcanism here,
we're still right next
to the lake,
we can see in Lac Vert,
the water table is right here.
There's all
the ingredients there
for this to happen again.
A powerful new eruption
along this densely populated
shoreline,
or in the city of Goma itself,
would have a devastating impact.
But there might be
warning signs.
As magma moves up
towards the surface
through underground cracks,
it forces the earth apart,
creating swarms
of mini-earthquakes,
which instruments
called seismometers can detect.
Joshua Subira
of the Goma Observatory
explains that seismometers
have been placed
next to the volcanoes
and along Lake Kivu
near the city of Goma.
This network of seismometers
is an essential tool
in the effort
to forecast eruptions here,
where so many lives are at risk.
But neither seismometers
nor cones like Lac Vert
can tell Chris and Kayla
whether the heat and magma
that create these volcanoes
is coming from a mantle plume.
I think we need to get deeper
into this landscape
and try and uncover
what's really driving everything
from the biggest,
biggest scale sense.
One place
they have yet to explore
could hold the answer.
Lake Kivu.
Joining Dario Tedesco
and Mathieu Yalire
from the Goma Volcano
Observatory,
Chris and Kayla head out
on the waters of the vast lake
that lies directly south
of Goma.
Lurking in its depths
is a huge hidden danger,
worse than anything
they've seen so far.
It could also hold
the vital clue
about whether a mantle plume
is driving
the volcanic activity here.
Maybe now we're ready to put
this thing in the water, yeah?
The key is to get a water sample
from the deepest part
of the lake.
Let's try not
to lose everything.
Mathieu and Dario drop
an open sample bottle
down to a depth of 55 meters,
about 180 feet.
50 meters...
and here we have 55 meters.
If you want to see it...
I'll stand it.
There it goes.
Yep.
We'll leave it.
A heavy weight
is then sent down the rope
to trigger the mechanism
that closes the bottle.
You can feel the weight of that,
you can feel
as I'm dragging it up,
pushing the water out of the way
as I bring this thing up.
I think at five.
Yes, here is it.
And look...
wait, wait wait.
Look at the...
the gas coming out.
Come, come here.
Oh, my gosh.
Yes, you see?
Like a carbonated drink,
the bubbles consist
of gas suddenly released
from the water sample.
This is the danger lurking
in the lake.
When you open...
You can hear it.
It's like opening
a bottle of pop.
Yeah, exactly.
You see see the...
It looks like a soda,
it's all completely carbonated.
It's 99% is carbon dioxide.
99%?
Yeah.
The bottom of the lake
contains the potentially lethal
suffocating gas,
carbon dioxide.
It's given off
by the constant
volcanic activity
beneath the Goma region,
seeping into the lake
from the underlying bedrock.
Its presence is
a serious threat.
Lake Nyos in Cameroon
also has volcanic carbon dioxide
trapped in its depths.
On the night of August 21, 1986,
a giant lethal pulse of the gas
escaped from the depths
of Lake Nyos,
flowing over the shoreline
and into surrounding fields
and villages.
Almost 2,000 people suffocated
as they slept,
and Lake Kivu
is far bigger than Lake Nyos.
All the lake has
a huge amount of CO2,
about, uh... 256
cubic kilometers.
That's enough gas
to cover an area
more than 50 times
the size of New York City
in a suffocating layer
20 feet deep.
The risk is that a
volcanic eruption or earthquake
could destabilize Lake Kivu,
releasing
its carbon dioxide gas,
threatening the lives
of thousands of people.
But there are efforts underway
to prevent that,
and the group is going to see
an experimental project.
This is one of the most
amazing things I have ever seen.
We're in this glass flat bay,
and all of a sudden,
you come to this platform,
and it's just...
all hell has broken loose.
It's a massive amount
of pressure that...
it's almost like a geyser
- just spewing stuff.
- It is a geyser.
It is a geyser?
It is a geyser,
and we don't see
the geyser itself,
just because
there is something on top.
The core that is just 50 meters
in order not to let
the geyser blow.
Salty water, another product
of volcanic activity,
seeps into the deeper sections
of the lake,
forming a dense layer
that acts like a lid,
trapping the carbon dioxide
below.
The aim is to find a way of
slowly releasing the trapped gas
at concentrations
that don't endanger people.
A pipe runs down
from the platform
into
the carbon dioxide-rich layers.
The water saturated with gas
flows up the pipe
in a controlled release,
allowing the carbon dioxide
to mix with the air,
making it harmless.
This is a pilot
to see if there is a way to
de-gas this part of the lake.
If it succeeds,
we make a very big one
to put the... a very big amount
of CO2 in the air.
The controlled release
of the carbon dioxide reservoir
at the bottom of the lake
could prevent a future disaster;
but it's a massive project
and very expensive,
although efforts
to commercialize methane,
or natural gas, also found
at the bottom of the lake,
could help defray the cost.
Meanwhile, the dangerous
carbon dioxide in Lake Kivu
provides a valuable clue
to what's driving the area's
many volcanoes.
Where is the carbon dioxide
actually coming from?
Most of the carbon dioxide
that we collect
all over the lake
comes straight
from the mountain.
This is probably
the best findings we have.
The carbon dioxide
they collect here
bears a distinctive
chemical signature,
revealing its origins were deep
in the mantle,
the thick layer
between the earth's crust
and its core.
Here in the Goma region,
the earth's mantle is
at least 20 miles
beneath the surface.
Only a giant mantle plume,
a huge upwelling of magma,
could bring gas up
from such a depth.
The idea that there's
a mantle plume underneath here,
there's some evidence
at the bottom of the lake,
I just never thought
that would be something
we'd find out.
It's really the last,
the last piece of the puzzle
in this landscape, I think.
The existence of a mantle plume
bringing up extreme heat
from the depths
means the East African Rift
will likely continue.
Africa may eventually
tear apart.
Fortunately,
not for many millions of years.
But the scientists believe
the energy unleashed
by the plume
explains the extraordinary
volcanic activity
witnessed
during their expedition.
The CO2 that's sitting
in the bottom of this lake,
all of the gases,
the sulfur that you can smell,
it's all coming straight
out of the mantle.
It's just streaming off,
this upwelling plume of material
that's delivering heat,
energy, chemistry
to the whole landscape.
To the volcanoes we've been on,
the bottom of this lake,
it's all connected
to the same huge process.
After three weeks
the expedition has come
to an end.
It's been grueling,
but the team has gained
unprecedented insights
into the volcanoes
that dominate this region.
On Nyamuragira,
their aerial survey is
an important step
toward predicting
future eruptions.
And in the depths of Lake Kivu,
they found evidence
that a vast mantle plume
drives the region's
intense volcanism,
which may ultimately
split Africa in two.
The people here
live side by side
with geological forces
that are reshaping
the face of our planet.
If you live in this
amazing, amazing place,
you can live with the hazards,
but the hazards cannot be
at the front of your mind
all the time.
It would just stop you
from doing anything, I'd guess.
The knowledge gained
on the expedition,
working with local scientists,
is vital to better prepare
the people of Goma
for future eruptions...
which are bound to occur.
We have two active
volcanoes now.
The city became very big,
many people in Goma.
The gas in Lake Kivu,
it will make problem.
Maybe we have to monitor
and continue to monitor,
to make warning in time.
These forces can be understood
but never completely controlled.
This will always be
one of the world's most
extraordinary places to live...
a landscape
of both deadly hazards
and incredible wonders.
We have this absolutely vast
volcanic landscape here,
and the people living
right on top of it.
It's my hope
that people can learn
to understand that landscape
better,
in order
to not only protect themselves
but also to reap the benefits
from it.
Hey!
From pain pills to fentanyl.
A parent's worst nightmare,
to find my kid not breathing.
A deadly epidemic.
Overdose is the number-one cause
of death
for people under 50.
But there are solutions.
We have life-saving medications.
A brain disorder
that can be treated.
Let's embrace addiction
as a disease,
bring it within the house
of medicine.
"Addiction," next
time, on "NOVA."
This "NOVA" program
is available on DVD.
"NOVA" is also available
on Amazon Prime Video.
are two of the world's
most dangerous volcanos.
Within their craters,
molten lava steams and boils.
Over centuries
these volcanoes have erupted
many times,
but when will they erupt again?
It's a crucial question,
and no one knows the answer
because these are among
the least-studied volcanoes
in the world.
Now an international team
of scientists
has come to investigate
these giants,
to predict future eruptions
and save lives.
Everything we do to understand
this volcano is very important
to avoid another disaster.
Today,
they're flying
to a volcano called Nyamuragira
in a region rife
with dangerous militias.
After many active years,
this volcano
has stopped erupting.
The fire in its crater
appears to be gone.
We need to collect some really
critical data up there
to understand
what might happen in the future.
Will Nyamuragira erupt again?
And if so, when?
The people who live here
are at risk.
Can scientists find a way
to protect them
before time runs out?
Right now,
I just want to get things set up
and going,
so we can just get
as much as possible
in this really short time
that we have here.
Can they solve the mystery
of "Volcano on the Brink"?
Right now, on "NOVA."
Major funding for "NOVA"
is provided by the following:
In a remote region
of central Africa
lies one of the most active
yet least explored volcanoes
on the planet:
Nyamuragira,
as spectacular
as it is mysterious.
The volcano sits
on the eastern border
of the Democratic Republic
of Congo, the DRC,
near the shores
of the vast Lake Kivu.
Fewer than 20 miles
from the volcano
is the town of Sake.
Its residents
are all too familiar
with the threat
of its frequent eruptions.
Market traders Terese Kalume
and Mama Noya
have spent their entire lives
here
and witnessed the effects
for themselves.
Nyamuragira eruptions blanket
large areas of farmland
in scalding-hot, choking ash,
destroying crops,
killing livestock,
and bringing famine.
At the moment,
there is just such a break.
It's been five years
since the last major eruption.
Has the volcano gone extinct,
or will it erupt again,
more deadly than before?
It's this question
that an international group
of scientists
has come to investigate.
To do that, they have to be
transported to the volcano
by a United Nations
peacekeeping team.
For British geologist
Chris Jackson,
it's a field trip like no other.
It's actually
in a fairly dangerous
part of the the area,
so the only way to get there is
with a military helicopter.
My heart's racing
just at the thought
of getting on that helicopter.
Few people have visited
Nyamuragira...
For good reason.
This region of the DRC
was the center
of one of the bloodiest wars
of modern times.
Fueled by
a long colonial history,
vast mineral wealth,
political tensions,
and international pressures,
millions were killed
and injured.
Although the war
is officially over,
widespread unrest continues.
Violent militia and rebel groups
are operating in nearby forests,
so the helicopter flies fast
at treetop level
to stay out of their gunsights.
Even at this speed,
the helicopter provides
a great vantage point
to see one
of the most volcanic places
on earth.
American volcanologist
Kayla lacovino
has studied volcanoes
across the planet,
but the volcanism here
is on a scale
she's never experienced.
I thought I knew
what this landscape
was going to look like,
but there's really
way more volcanoes,
way more melt here
than I expected.
It's... the amount of
magma production in this region
is insane.
As they reach Nyamuragira,
they can see
it's a giant shield volcano,
so called
because successive lava flows
have spread widely
across the landscape,
giving its surface
a sloping, shield-like shape.
The volcano rises
to over 10,000 feet,
surrounded by old lava flows
that blanket
almost 600 square miles.
At the summit,
the main caldera created
by previous eruptions
is over a mile across,
with 300-foot-high walls
and, at its center,
a 600-foot-deep crater.
Usually such an active volcano
near so many people
would be covered
in monitoring equipment,
but because it's remote
and dangerous,
Nyamuragira has none.
This is a rare opportunity
to gather data
for predicting future eruptions.
We're hoping to land
on top of the volcano,
right next to its active crater.
We need to collect some
really critical data up there
to understand what might happen
in the future.
This is one of Africa's
most active volcanoes,
and it has
a very complex history.
During the past 100 years,
it's erupted from its flanks
at least 30 times,
flooding the surrounding
farmland in molten rock,
though this hasn't happened
for the past five years.
In 2014,
for the first time
in almost a century,
a small lava lake developed
in the center of the crater.
So, the first thing
the scientists want to check
is whether that lava lake
is still there.
We're banking round now.
There's just sheer cliffs
right down to the lava lake,
which,
from what I can see
at the moment, seems to...
seems to be crystallized,
so seems to have turned
into rock.
But does this
have anything to do
with the volcano's behavior?
With the lava lake
apparently gone,
will the volcano return
to its cycle
of huge, destructive eruptions?
Belgian geologist Benoît Smets,
who works with local scientists,
specializes in geo-hazards.
I think we should first follow
the, the cracks...
Okay.
And then turn right right, try
to avoid them. Okay, cool.
He discusses plans
with Aldo Kane,
a former Royal Marine,
who's in charge
of the expedition's safety.
Across the caldera,
this is where the gas escapes,
so it's quite dangerous.
Okay, all right, we'll
get everyone out,
and then we'll get
a bit of a brief then.
Okay.
It's not just the volcano
that worries Aldo.
Just to be aware
there are armed groups
operating in and around
the, the slopes of the volcano.
If you do see someone
that's not from our group,
then get on the radio,
let me know.
There is a path and tracks
going through here,
so they are using it,
it is accessible to them,
so keep your eyes peeled.
Any armed groups
that saw them fly in
could be heading to the summit,
so they can't stay long.
So, we've got two hours,
so we need to be back here,
everyone at the chopper
ready to go in two hours.
- Cool?
- Okay, sounds good.
Thanks, Aldo.
The urgent question for the team
is whether the current break
in large-scale eruptions
is coming to an end.
Kayla believes that the plume of
gases released by the volcano
will yield vital clues.
I want to find a place
where I can actually get
inside the plume
and put the gas box,
and that can tell me more
about the different chemicals
that are coming out
of the plume.
Monitoring the changes
in that gas chemistry
is what tells us whether
the system is changing,
whether it's moving
towards an eruption,
whether there's new, new magma
being input at the very base.
The gases really tell
the whole story.
Most volcanoes have
a magma chamber,
a reservoir of molten rock
deep underground
that fuels eruptions.
As the magma rises up
towards the surface,
it releases a mixture of gases.
A sudden increase in one gas,
called sulfur dioxide,
often signifies
an imminent eruption.
Kayla wants to discover the
concentration of sulfur dioxide
in the gas plume, but
it won't be easy.
I'm really...
yeah, I feel, I feel like
we're really pushed for time
here.
There is a lot of gas
coming out of here.
The problem for me is that
once it gets to the top,
it's, it's become
pretty diffuse,
which is why I'm having
to chase the plume around.
The team also needs to check
on activity
in the lava lake.
Kasereka Mahinda,
a geophysicist,
knows the summit
better than anyone
and can identify the best place
to see into the crater.
The best place to...
The best place is there,
because one time I stayed there,
you can see around the crater.
- Okay.
- Yeah.
Most eruptions are driven
by a build-up of pressure
inside a volcano.
It's possible that the lava lake
that appeared in 2014
acted like a safety valve,
an open vent releasing pressure.
When Kasereka was last here,
the lava lake was still active,
a small cone erupting
in its center.
I was here,
you have active lava
in the crater,
very big, active lava.
But now, from the helicopter,
it looks as though
the lava lake
is no longer active.
If so, then the volcano
may have lost its safety valve
and could now be building
towards a major eruption.
With only two hours to try
and find out what's happening,
the team decides to split up.
Kayla heads off on her own
to get a gas sample,
while Kasereka leads the others
to the vantage point
overlooking the crater.
Kasereka works
at the Goma Volcano Observatory,
which carries out research
on volcanoes across the region.
The observatory's job
is not only to monitor
the risk of eruptions
but also the long-term effects
of living in such
a volcanically active area.
We look at the whole landscape,
you know, it's about...
they... all volcanoes
in the landscape, that's one.
But mainly we focus
on the two active volcanoes.
Still... we still also
monitoring the rest.
We do also measure the quality
of water people are drinking
to advise
the health authorities.
Mathieu Yalire
studies volcanic gases.
Together with fellow
volcanologist Dario Tedesco,
he's investigating
the volcano's effect
on the water supply in Sake.
This is part of our
job, to analyze water,
all samples we can get
around the region.
Volcanoes tap the inner earth,
releasing certain elements
into the environment
in much higher levels
than normal.
Some can be harmful.
Mathieu and Dario are interested
in one particular element:
fluorine, that dissolves
in water to form fluoride.
Many of the townspeople
have brown, stained teeth.
Not a sign of neglect
but possibly a condition
known as fluorosis,
too much fluoride in their diet.
Around the world
sodium fluoride is often added
to drinking water.
At low concentrations,
it helps prevent cavities,
but at higher levels,
it can cause problems.
Mathieu and Dario measure
the levels of fluoride.
The limit of this machine
is ten part per million,
and it says, "Over the limit."
The water has levels of fluoride
around ten times
the recommended safe limits...
Concentrations
that can damage teeth,
bones, joints,
and even organ function.
And there is no easy remedy.
At present, we really don't have
any solution,
because the best solution
would be to bring water
from very far from here,
in, uh...
Masisi.
Masisi, Masisi area.
It's a very... It's
20, 30 kilometers.
This is not only this village.
It's more or less
100,000 people or more
that live in the area.
There's another effect
of the elements thrown out
by the volcano,
one that benefits the community.
Between eruptions,
the lava and ash break down,
releasing nutrients
into the soil
and creating incredibly rich
and productive farmland.
It's why the market
is full of food.
For local people,
this combination
of risks and benefits
can lead to a complex mindset
of both fear and appreciation
of the volcano.
Back on Nyamuragira,
the scientists are trying
to figure out
what the volcano will do next.
Kasereka Mahinda
from the Goma Observatory
is leading them to a viewpoint
over the crater
to help them assess
if the lava lake
that formed in 2014
is still active.
Oh, wow.
As you walk towards the edges
of these craters,
you get that feeling
in your stomach,
like you're about to go off
the edge of the world.
The crater is dark.
It looks as though
the activity Kasereka observed
in the lava lake
has now stopped.
To be sure,
Benoît and his colleagues
set up a thermal camera
to check
if there's any magma moving
beneath the thin crust
of black rock.
But that means getting
uncomfortably close to the edge.
Just go careful on that edge,
this entire edge,
even under where
your camera is there,
is over-hanging.
That's millions of tonnes
of rock there,
and they're right
on the edge of it.
They check the temperature.
Intense heat would mean
the vent is still active.
So what's the temperature
down on the base?
So everything has
the quite same temperature,
about 45 to 50 degrees Celsius.
Although quite hot,
50 degrees Celsius,
or 120 degrees Fahrenheit,
is not hot enough
for there to be magma
near the surface.
It's totally dead.
No activity left at all.
And the question is now,
is it just a break
or is it just finished?
It means that
the activity may change.
With no active lava
and a solidified crater floor,
pressure could be building
inside the volcano.
The volcanic activity
that we see
is only a very very small part
of the real volcanic activity.
There is much more happening
below the surface.
Some of the best clues
of what's happening
beneath the surface
are the gases given off
by the volcano.
They could reveal
if new lava is rising up inside,
threatening an eruption.
That makes
Kayla's gas measurements
all the more important.
But getting a sample
is proving difficult.
Unfortunately, the best place
where the gas is coming up
is also on, I think,
the most precarious part
of the entire crater rim.
It's why I'm not over there,
where its gassiest.
Is that... these thick
layers of ash,
that looks like
the most unstable,
but I'm just trying to get
as close as I can
without being unsafe.
Given the dangers
of gathering data,
Kasereka sets up
a simple instrument
he knows will be helpful
in understanding the volcano.
I need to set up my...
You're setting up here?
Yeah?
The observatory is trying
to establish a set
of baseline measurements
to spot changes in the volcano
that could signal an eruption.
So what are you gonna
set up here?
I set up the thermometer
to measure the temperature.
So, temperature measurements?
Yes.
Kasereka's focus
is the fumaroles
found across the crater,
cracks and openings
that can reach all the way down
to the magma chamber.
Measuring their temperature
can reveal what's happening
deep inside the volcano.
You know, we'll see if there,
the temperature increase or not.
Okay.
So I can tell if the magma
is coming up or not.
As magma moves up
inside the volcano
before an eruption,
the fumarole temperature
increases dramatically.
But to spot that,
a set of baseline measurements
is essential.
We've lowered the probe in
about a meter, meter and a half.
Yeah, this one will record
every five minutes;
Okay.
I try to reduce the minutes
because we don't have
enough time.
There's no screen
on the data logger,
so we can't see what the
temperatures are at the moment.
We have to wait
till we go back and plug it in.
Yeah, I have to go back
to my office,
Okay... okay.
'cause I have some software
to analyze, yeah.
This kind of data
could ultimately help
predict future eruptions.
With little time remaining,
Benoît is also determined
to squeeze in
one last experiment
that could reveal pressure
building within the volcano.
I would like you to follow
the drone with binoculars
to be sure I don't crash it.
Years of observations
around the world
have shown that
before an eruption,
increasing pressure can change
the shape of a volcano,
making it swell.
Perhaps the most extreme example
is Mount St. Helen's
in Washington state.
In 1980,
the north side of the volcano
bulged outwards some 270 feet
just a month
before its violent eruption.
Usually scientists are looking
for much more subtle changes,
which can take months
of monitoring
with a whole range
of ground-based sensors.
That's not possible here,
so Benoît has come up
with a high-tech solution.
I'm using a drone to take
pictures of the big crater
in different viewpoints.
And with this set of images,
I will be able to create
a 3D model of the big crater.
The computer model
Benoît creates
is a 3D snapshot of what
the crater looks like today.
Comparing it to images captured
on future visits
will allow him to spot
small changes in the terrain,
which may precede
an impending eruption.
Benoît has just enough time
to finish his survey.
The two hours are up,
and weather is closing in.
We are a long way
from the helicopter,
and there's a huge bank of cloud
that's coming our way,
so I think we take
the weather window
and we bug out.
If the storm hits,
the helicopter will not be able
to take off,
leaving the team stranded
on the summit.
If you need me to carry
anything, let me know.
Okay. There's some
space in my pack.
And we still need
to pick Kayla up
on the way as well,
'cause she's still
over there doing her gas box.
It's been a frustrating day
for Kayla,
who hasn't managed to capture
any useful data.
It's just so hard to work
in places like this,
where access
is nearly impossible,
and then when you get access,
you have two hours.
It's just not enough.
Even so,
this rare visit
has been worthwhile.
They've confirmed that the
lava lake that appeared in 2014
is no longer active,
raising the possibility
that the volcano may once again
be building
towards a major eruption.
If so,
the new monitoring equipment
they've left behind
may help forecast that event.
As the team departs,
they turn their attention
to another goal
of their expedition:
investigating what makes
this part of Africa...
so intensely volcanic.
It's amazing from up here,
the view you get.
From the ground,
it was spectacular,
but from here,
it is absolutely something else.
This is flat land
with these volcanoes
just punching through
absolutely everywhere.
The entire area is filled with
evidence of volcanic activity.
Each one of these small hills
is an extinct volcanic cone.
But what is the impact
of living
in such a volcanic landscape?
To find out,
the team travels to Goma,
a city of almost
a million people
that lies south of Nyamuragira
and another giant
volcano, Nyiragongo.
Nyiragongo last erupted in 2002,
sending rivers of lava
into the heart of Goma,
causing death and destruction.
The city has since recovered
and is growing.
Today Chris and Aldo are heading
to a local boxing gym.
Wow, check this out.
They're here to learn
about the relationship
between the area's
volcanic history,
its ongoing instability,
and what local people are doing
to address the trauma
of violence.
Continuing unrest here
means that children
often have little choice
but to fight in the armed gangs
and militias
that operate around Goma.
Some of the men in this gym
were once child soldiers.
The discipline of boxing
provides a way for them
to escape their violent past.
The continuing unrest
and use of child soldiers
are driven by the extraordinary
mineral wealth of the region,
especially one mineral
that plays a crucial role
in modern life.
This is the mineral coltan,
this dark-colored mineral here.
It's the kind of mineral
I'd expect to find
in an area like this.
And any touchscreen phone,
laptop,
anything with a transistor
will have tantalum,
which is the tan of the coltan.
The explosion in smartphones
and other electronics
means coltan is
in constant demand.
Even small mines
can generate huge profits,
but in this region,
militias control
many of the mines.
The income means
they can recruit young people,
fueling the ongoing violence.
It's very hard to hold this
in your hand,
knowing how much we desire it,
and knowing
what it leaves behind
and where it comes from.
Bonjour, Kibo.
The head of the gym, Kibomango,
is a former child soldier
who now tries
to help young people
rebuild their lives.
And you're happy for us to join
in some, some training?
Joining, joining,
no problem, no problem, yes.
Aldo's fascinated
by Kibomango's story,
because like him, Aldo became
a soldier at an early age.
So, Kibo,
when did you join the army?
Which is two years younger
than I was when I joined up.
How long did you serve
in the, uh, in the army?
Although Aldo joined
the Royal Marines at 16,
legally he couldn't see
frontline action
until he was 18,
unlike Kibomango
and the young people here.
I wouldn't mind betting that
what Kibomango's doing here
to run this boxing club
is partly for his own therapy.
As a child soldier,
he's going to have seen
some pretty nasty stuff.
After the workout,
Aldo has a chance to take on
the man himself.
Kibomango is
a former Congolese champion.
In a poor and job-starved area,
militias are one
of the few sources
of money and employment.
It's a vicious cycle.
The chaos in the region
helps gangs control
the mineral wealth,
and in turn the mineral wealth
allows the gangs
to maintain the chaos.
There are efforts underway
to break the cycle
by promoting a more sustainable
use of the resources
created by the volcanoes.
They focus on
the Virunga National Park,
a vast nature reserve covering
around 3,000 square miles.
Its fertile volcanic soils
make it one of the
most diverse parks on the planet
and one of the few places
where it's still possible
to see mountain gorillas.
These highly social animals
thrive in this lush
forest habitat,
eating mainly leaves, shoots,
and stems.
Thousands of people come to see
the gorillas,
generating cash that's used
to create local jobs.
But following attacks
by poachers and criminal gangs,
the park had to close
temporarily,
another setback for a region
where volcanic riches
have the potential
to create
a very different future.
But what makes this area
so volcanically active
in the first place?
It's a question the scientists
are determined to answer.
From the helicopter,
I got a, like, almost
a once-in-a-lifetime view
of the entire
volcanic landscape.
And what really struck me
was the amount of volcanism
and the amount
of volcanoes here.
We have hundreds
and hundreds of them.
This extraordinary concentration
of volcanic activity
is related to a vast chain
of mountains and valleys.
The East African Rift.
It's a massive
geological feature...
stretching nearly 4,000 miles
up the eastern side
of the continent,
and the Goma volcanoes are
at the midpoint of the rift.
The earth's outer crust
is divided into giant slabs
called tectonic plates.
Along the East African Rift,
the tectonic plate is splitting,
and the two sides of the rift
are moving away from each other
as the continent
slowly rips apart.
If the split continues
over millions of years,
a new ocean
and continent will form.
But many rifts
don't fully develop.
The waters of the Mississippi
now fill the scar left
by a failed rift
when a huge section
of what's now the Midwest
started to tear apart
around a billion years ago...
And then stopped.
Will the East African Rift
also fail?
The answer hinges
on a controversial theory.
So, one thing it could be
is something called
a mantle plume,
that's a column
of deep, hot material,
which is rising up
towards the earth's surface.
As it comes
to the earth's surface,
it can weaken the plate,
and it can actually
force the plates apart,
but some of that melts,
some of that magma
can also come out
onto the earth's surface
and build volcanoes.
The earth's mantle lies
between its dense core
and its thin crust.
The presence of a mantle plume,
a huge column of heat
and melted rock
rising from deep
beneath the region,
would explain why there
are so many volcanoes here.
If a plume exists,
then the enormous heat
and energy it brings
could keep the rift active
long enough
to split Africa apart.
Like all geological theories,
we really need to go out
into the landscape
and look
for additional evidence.
So along with Kayla,
Chris goes on the hunt
for evidence of
a distinctively deep upwelling
of heat and magma,
the signature of a mantle plume.
The first place
they want to look
is one of the extinct
volcanic cones,
common in the region.
I'm really interested to see
some of the smaller cones,
because we've been looking
at Nyiragongo, Nyamuragira,
you know, the big boys.
There's so much information that
the smaller cones can have too.
Their destination is Lac Vert,
the "Green Lake,"
just outside Goma.
Wow, look at that.
Today it's a 300-foot climb down
from the crater rim to the lake.
People bathe
and wash clothes here,
but around 500 years ago,
this was an active volcano.
Chris and Kayla want to know
what sort of eruption
formed Lac Vert,
and whether it could be linked
to the presence
of a mantle plume.
They also want to find out if
this volcano could erupt again,
and what that would mean
for the city of Goma.
They start
by examining the rocks
that make up the volcanic cone.
For many years
the sides have been quarried,
so with a little effort...
You got to go over the head.
Over the head?
Yeah.
It's easy to get their hands
on some samples.
None of this is actually lava,
this is all ash,
these are all ash deposits.
And that means this was magma
that came up through the ground,
was exploded onto the surface
and absolutely ripped apart
into very, very fine pieces
that you can see here.
Imagine how much energy
it would take
to take solid rock,
and, and just explode it
into these tiny, tiny bits.
That screams to me that
there was an interaction
with the water
when this actually erupted.
Goma sits in the middle
of a string of craters
like Lac Vert,
each formed
by explosive eruptions,
and each capable of delivering
a devastating blast.
The eruptions are caused
by magma welling up
from underground.
When the magma hits a layer
saturated with water,
the extreme heat instantly
turns the water to steam,
triggering a powerful explosion.
This generates huge amounts
of fine-grained ash,
just like the deposits
found here...
Clear evidence that Lac Vert
was formed by this type
of explosive eruption.
The sides of the crater
also reveal something else:
this wasn't a single event.
What strikes me,
as somebody who's interested
in sedimentology,
is how many layers of rock
there are like this.
The layering
in the rock behind us,
I wouldn't want to go over there
and count them,
but there's clearly hundreds
and hundreds
of giant explosions
associated with
this catastrophic eruption.
It may be about five centuries
since the last eruption,
but the danger of a new one
is very real.
We've still got lots
of volcanism here,
we're still right next
to the lake,
we can see in Lac Vert,
the water table is right here.
There's all
the ingredients there
for this to happen again.
A powerful new eruption
along this densely populated
shoreline,
or in the city of Goma itself,
would have a devastating impact.
But there might be
warning signs.
As magma moves up
towards the surface
through underground cracks,
it forces the earth apart,
creating swarms
of mini-earthquakes,
which instruments
called seismometers can detect.
Joshua Subira
of the Goma Observatory
explains that seismometers
have been placed
next to the volcanoes
and along Lake Kivu
near the city of Goma.
This network of seismometers
is an essential tool
in the effort
to forecast eruptions here,
where so many lives are at risk.
But neither seismometers
nor cones like Lac Vert
can tell Chris and Kayla
whether the heat and magma
that create these volcanoes
is coming from a mantle plume.
I think we need to get deeper
into this landscape
and try and uncover
what's really driving everything
from the biggest,
biggest scale sense.
One place
they have yet to explore
could hold the answer.
Lake Kivu.
Joining Dario Tedesco
and Mathieu Yalire
from the Goma Volcano
Observatory,
Chris and Kayla head out
on the waters of the vast lake
that lies directly south
of Goma.
Lurking in its depths
is a huge hidden danger,
worse than anything
they've seen so far.
It could also hold
the vital clue
about whether a mantle plume
is driving
the volcanic activity here.
Maybe now we're ready to put
this thing in the water, yeah?
The key is to get a water sample
from the deepest part
of the lake.
Let's try not
to lose everything.
Mathieu and Dario drop
an open sample bottle
down to a depth of 55 meters,
about 180 feet.
50 meters...
and here we have 55 meters.
If you want to see it...
I'll stand it.
There it goes.
Yep.
We'll leave it.
A heavy weight
is then sent down the rope
to trigger the mechanism
that closes the bottle.
You can feel the weight of that,
you can feel
as I'm dragging it up,
pushing the water out of the way
as I bring this thing up.
I think at five.
Yes, here is it.
And look...
wait, wait wait.
Look at the...
the gas coming out.
Come, come here.
Oh, my gosh.
Yes, you see?
Like a carbonated drink,
the bubbles consist
of gas suddenly released
from the water sample.
This is the danger lurking
in the lake.
When you open...
You can hear it.
It's like opening
a bottle of pop.
Yeah, exactly.
You see see the...
It looks like a soda,
it's all completely carbonated.
It's 99% is carbon dioxide.
99%?
Yeah.
The bottom of the lake
contains the potentially lethal
suffocating gas,
carbon dioxide.
It's given off
by the constant
volcanic activity
beneath the Goma region,
seeping into the lake
from the underlying bedrock.
Its presence is
a serious threat.
Lake Nyos in Cameroon
also has volcanic carbon dioxide
trapped in its depths.
On the night of August 21, 1986,
a giant lethal pulse of the gas
escaped from the depths
of Lake Nyos,
flowing over the shoreline
and into surrounding fields
and villages.
Almost 2,000 people suffocated
as they slept,
and Lake Kivu
is far bigger than Lake Nyos.
All the lake has
a huge amount of CO2,
about, uh... 256
cubic kilometers.
That's enough gas
to cover an area
more than 50 times
the size of New York City
in a suffocating layer
20 feet deep.
The risk is that a
volcanic eruption or earthquake
could destabilize Lake Kivu,
releasing
its carbon dioxide gas,
threatening the lives
of thousands of people.
But there are efforts underway
to prevent that,
and the group is going to see
an experimental project.
This is one of the most
amazing things I have ever seen.
We're in this glass flat bay,
and all of a sudden,
you come to this platform,
and it's just...
all hell has broken loose.
It's a massive amount
of pressure that...
it's almost like a geyser
- just spewing stuff.
- It is a geyser.
It is a geyser?
It is a geyser,
and we don't see
the geyser itself,
just because
there is something on top.
The core that is just 50 meters
in order not to let
the geyser blow.
Salty water, another product
of volcanic activity,
seeps into the deeper sections
of the lake,
forming a dense layer
that acts like a lid,
trapping the carbon dioxide
below.
The aim is to find a way of
slowly releasing the trapped gas
at concentrations
that don't endanger people.
A pipe runs down
from the platform
into
the carbon dioxide-rich layers.
The water saturated with gas
flows up the pipe
in a controlled release,
allowing the carbon dioxide
to mix with the air,
making it harmless.
This is a pilot
to see if there is a way to
de-gas this part of the lake.
If it succeeds,
we make a very big one
to put the... a very big amount
of CO2 in the air.
The controlled release
of the carbon dioxide reservoir
at the bottom of the lake
could prevent a future disaster;
but it's a massive project
and very expensive,
although efforts
to commercialize methane,
or natural gas, also found
at the bottom of the lake,
could help defray the cost.
Meanwhile, the dangerous
carbon dioxide in Lake Kivu
provides a valuable clue
to what's driving the area's
many volcanoes.
Where is the carbon dioxide
actually coming from?
Most of the carbon dioxide
that we collect
all over the lake
comes straight
from the mountain.
This is probably
the best findings we have.
The carbon dioxide
they collect here
bears a distinctive
chemical signature,
revealing its origins were deep
in the mantle,
the thick layer
between the earth's crust
and its core.
Here in the Goma region,
the earth's mantle is
at least 20 miles
beneath the surface.
Only a giant mantle plume,
a huge upwelling of magma,
could bring gas up
from such a depth.
The idea that there's
a mantle plume underneath here,
there's some evidence
at the bottom of the lake,
I just never thought
that would be something
we'd find out.
It's really the last,
the last piece of the puzzle
in this landscape, I think.
The existence of a mantle plume
bringing up extreme heat
from the depths
means the East African Rift
will likely continue.
Africa may eventually
tear apart.
Fortunately,
not for many millions of years.
But the scientists believe
the energy unleashed
by the plume
explains the extraordinary
volcanic activity
witnessed
during their expedition.
The CO2 that's sitting
in the bottom of this lake,
all of the gases,
the sulfur that you can smell,
it's all coming straight
out of the mantle.
It's just streaming off,
this upwelling plume of material
that's delivering heat,
energy, chemistry
to the whole landscape.
To the volcanoes we've been on,
the bottom of this lake,
it's all connected
to the same huge process.
After three weeks
the expedition has come
to an end.
It's been grueling,
but the team has gained
unprecedented insights
into the volcanoes
that dominate this region.
On Nyamuragira,
their aerial survey is
an important step
toward predicting
future eruptions.
And in the depths of Lake Kivu,
they found evidence
that a vast mantle plume
drives the region's
intense volcanism,
which may ultimately
split Africa in two.
The people here
live side by side
with geological forces
that are reshaping
the face of our planet.
If you live in this
amazing, amazing place,
you can live with the hazards,
but the hazards cannot be
at the front of your mind
all the time.
It would just stop you
from doing anything, I'd guess.
The knowledge gained
on the expedition,
working with local scientists,
is vital to better prepare
the people of Goma
for future eruptions...
which are bound to occur.
We have two active
volcanoes now.
The city became very big,
many people in Goma.
The gas in Lake Kivu,
it will make problem.
Maybe we have to monitor
and continue to monitor,
to make warning in time.
These forces can be understood
but never completely controlled.
This will always be
one of the world's most
extraordinary places to live...
a landscape
of both deadly hazards
and incredible wonders.
We have this absolutely vast
volcanic landscape here,
and the people living
right on top of it.
It's my hope
that people can learn
to understand that landscape
better,
in order
to not only protect themselves
but also to reap the benefits
from it.
Hey!
From pain pills to fentanyl.
A parent's worst nightmare,
to find my kid not breathing.
A deadly epidemic.
Overdose is the number-one cause
of death
for people under 50.
But there are solutions.
We have life-saving medications.
A brain disorder
that can be treated.
Let's embrace addiction
as a disease,
bring it within the house
of medicine.
"Addiction," next
time, on "NOVA."
This "NOVA" program
is available on DVD.
"NOVA" is also available
on Amazon Prime Video.