Nova (1974–…): Season 43, Episode 4 - Himalayan Megaquake - full transcript

On April 25, 2015 a devastating earthquake rocked Nepal, wiping out villages and leaving thousands dead. Through eyewitness footage, expert interviews, and stunning graphics, NOVA reveals the anatomy of this megaquake while scientists race to answer urgent questions: Is another big one coming?

Are you wondering how healthy the food you are eating is? Check it -
Powerful tremors
catch millions by surprise.

There was a very
violent earthquake.

NARRATOR: Collapsing
buildings kill thousands.

Many are buried alive.

ANDREW OLVERA: And we're going to go
ahead and have the rescue squad come in

and help extricate that victim
out of the hole.

NARRATOR: It's the biggest quake
to happen here in 80 years.

Major earthquake!

We've never seen
anything like it!

CLIMBER: Oh, look at that,
look at that, look at that!

NARRATOR: The quake triggers a
huge avalanche on Mount Everest,

killing 20 people.

Whoa, whoa, whoa, inside!

NARRATOR: It's the Himalayan
peak's most deadly day.

It looks like what you see

when one of these tornadoes
runs right through a place.

I've never seen anything
come at us like that before.

NARRATOR: Millions across
Nepal are homeless.

Many are cut off from the world
by landslides.

SURAJ VAIDYA: They've lost all
the houses that they had.

The whole village is wiped out.

NARRATOR: Even scientists are stunned
by the powerful aftershocks.

Whoa, that was enormous!

ANDREW: Oh my gosh, it's like the
whole mountain's coming down!

We've seen just one fraction
of a second

in a 50 million year
time interval

of building the Himalayas.

NARRATOR: Can they forecast when
the next big one will strike?

You know, it's really scary.

There's no reason
why one could not occur

in the next ten years
or the next ten minutes.

NARRATOR: The race is on
to unravel the mysteries

of the "Himalayan Megaquake,"
right now on NOVA.

Major funding for NOVA is
provided by the following...

In this hilly terrain,
almost all arable land is used.

The slopes stretch up

to eight of the world's
ten highest mountains.

Each spring,
hundreds of mountaineers come

to climb Mount Everest,
the highest point on Earth.

The birthplace of the Buddha,

Nepal is a peaceful haven
for both Buddhists and Hindus.

Ancient palaces
stand side-by-side

with even older Hindu temples.

April 25, 2015, 11:56 a.m.


The earth begins to move

and doesn't let up
for a full minute.


There's no safe place to run.

Whoa, whoa, whoa, inside!

NARRATOR: An earthquake
rips across the Himalaya...

DEVANEY: Get down, get
down, get down, get down!

Close the door!

Close the door!

unleashing an avalanche

upon hundreds
at Everest's Base Camp.


I've never seen anything
come at us like that before.

Oh my God.

Oh my God!

Are you okay?


Are you all right?


NARRATOR: Survivors
quickly become rescuers.


Makeshift hospitals spring up

to deal with the nearly
18,000 injured.

Many are still buried alive.

Eight-year-old Seema Tamang
was trapped under her house.

She can't walk,
has a head injury,

but medical care is limited.

NARRATOR: There's a race to find
anyone alive in the rubble.

NARRATOR: Since April 25,
seismometers across Nepal

have recorded 400 aftershocks
of magnitude four or greater.

NARRATOR: Over two million
are now homeless.

Shaking isn't the only threat.

Over 5,000 landslides

have left thousands of villages

SURAJ VAIDYA: They're cut
off from the rest of Nepal,

and they've lost all the houses
that they had.

The whole village is wiped out.

They have supplies
for about 11 days.

And she's not sure what she's
going to do after 11 days,

but she's hoping that
the government will come

and give some sort of rescue,

you know,
drop some food up here.

So living for them is extremely,
extremely difficult

at this stage.

This used to be a cow shed,

and now what you have is
people actually occupying this

for their shelters, yes?

So you see there are four
little children up here.

They live up here, you see
they live in the middle?

That's how they're living.

NARRATOR: As the death
toll rises toward 8,000,

a few miracles emerge
from the dust.

Rescuers dig a baby boy out

from underneath his home
on day two.

Remarkably, he's unharmed.

This earthquake came
without warning.

People in the central mountain
villages felt it first.

Then, just 16 seconds later,
the shaking reaches the capital.

The waves rock people
like a storm at sea.

The tremors take only a minute
to reach Mount Everest,

150 miles away.

The ground is shaking!

Do you hear that?

Irish climber Paul Devaney

picks up his camera
to record what's happening.

We realized,
"Wow, this is an earthquake

and the whole of the base camp
is moving pretty violently."

Then, up above them,

the earthquake dislodges
a massive block of snow and ice,

which comes hurtling down.

But they can't see it.

BREASHEARS: I think probably
if it had been a clear day,

people would've seen
that avalanche much sooner.

NARRATOR: Photographer David Breashears
was on the mountain that day.

They had no time
by the time they turned around.

CLIMBER 1: Oh, look at that,
look at that, look at that.

Oh, look straight ahead.

Ready to go in the tents,
or what?

That is immense.

Look, look, look, look, look!

Ready to go in the tent?

NARRATOR: The climbers have a few
seconds to decide where to run.

I'd say within about 50 feet
of our location,

a massive avalanche
was bearing down on us.

Oh, oh!

Look, look!

Whoa, whoa, whoa, inside!

At that point in time,
you're just focused on,

"How can I survive this,
and will I survive this?"


Come under my jacket!

Come under my jacket!

Are you okay?

MAN: Yeah, yeah, yeah.

Are you all right?

MAN: Yeah.


DEVANEY: I've never seen anything
like that cloud come at us before.

Are you okay?

BREASHEARS: We started to learn,
three or four hours later,

that there had been
loss of life.

Many casualties,
people with serious injuries,

multiple broken bones,

Then every few hours,
the death count went up.

These were massive
blunt force trauma injuries.

People were blown
through the air into rocks.

NARRATOR: Ultimately 20
people die on Everest,

and in the rest of Nepal,
the total dead nears 9,000.

News of the devastation
travels faster

than the seismic waves

As the earthquake's waves
ripple out,

they hit seismic stations
at different times.

It takes 24 minutes for them

to reach the other side
of the Earth,

in Colorado,
where the U.S. Geological Survey

can compare the time they took
to reach each station

and then pinpoint
where the waves started...

the epicenter.

This one started 50 miles
northwest of Kathmandu.

But word travels hundreds of
times faster via social media.

HARLEY BENZ: We monitor for the word
"earthquake" in many languages.

We saw a surge
in Twitter traffic.

Realizing it was
in a heavily populated area,

an area that we know large
earthquakes can do damage,

I was called at home.

Within a few minutes,
our seismic sensors

will start seeing
this earthquake,

and then we'll locate
the earthquake,

determine its magnitude.

NARRATOR: Magnitude is the
size of the earthquake

at its source.

This one's 7.8...
sometimes called a "megaquake,"

an earthquake
that's seven or greater.

Earthquake magnitude
is not linear.

The 2010 quake in Haiti at 7.0

had the energy
of 32 Hiroshima bombs.

Nepal's 7.8 is more than
15 times stronger,

but not as large as this
highly active zone can produce.

Geologist Roger Bilham
is a first responder

to most of the world's
major earthquakes.

I immediately had a look

to see how much money we had
in the bank,

and I purchased a ticket
on the next flight to Kathmandu.

NARRATOR: He's especially
interested in the Himalayan region

because of its unique
geologic history.

The earth's crust consists
of several tectonic plates.

About 50 million years ago,
one of them, the Indian plate,

began colliding with Eurasia,
gradually forcing it upwards,

creating a massive
mountain range...

the Himalayas.

That's what builds
the Himalayas.

Where you have compression
of two plates,

the plates initially
start to fold and fracture.

The Himalayas is probably
the largest collision

that we've seen on the planet
for the last 500 million years.

NARRATOR: The Indian plate
continues to converge with Tibet

at the rate
of 18 millimeters a year.

In some places,
the plates stick,

accumulating stress,

which eventually releases
all at once in an earthquake.

This is what scientists believe
happened on April 25, 2015.

My god!

SEARLE: We've seen just
one fraction of a second

in a 50 million year
time interval

of building the Himalayas.

NARRATOR: This blip
in the geological timeline

was so powerful, it wiped out
thousands of villages.

Rescue has been slow to arrive.

A team of Nepalese athletes
and nurses

takes matters
into their own hands.

They gather tents, tarps,
and food

to deliver
to the cut-off villages.

travelling to the district

with the highest death toll:

Few vehicles have passed here
since the earthquake.

NARRATOR: They want to get
food and medical supplies

as far as the bus
will take them.

Then, they'll set up a hospital
for survivors.

All homes here are abandoned.

This road was just dug out

from an earthquake-triggered

A strong aftershock
could cause another.

NARRATOR: They reach the
village of Thulo Bhotang.

Over 3,400 people have died
in this district.

NARRATOR: They've brought 3,000
pounds of rice and lentils

to feed the villagers.

NARRATOR: Seema Tamang was literally
buried alive by the earthquake,

pinned beneath the stones
of her home for an entire day.

NARRATOR: Unable to walk,
Seema is in a lot of pain.

The doctors believe
she could have broken bones.

An x-ray is needed,

so she'll have to be evacuated
to Kathmandu.

NARRATOR: 95% of the structures
in this district were destroyed,

including Seema's home.

(speaking Nepali)


NARRATOR: But among the less
lucky ones is this young woman,

whose mother
and baby sister died.

(translated): I live in
Kathmandu... I have a job there.

My mother and sister died

in the earthquake.

I came back here,
and now I live in a cow shed

with my brothers and sisters.

One brother doesn't even know
that mother has passed away.

I haven't been able to tell him.

He's only seven years old.


I can't stay here
because I don't have land here.

Landslides have destroyed
all the lands we had.

The earthquake
has rendered us homeless.

Sometimes, I wish I were dead,

thinking that
it would be better.

This is the house.

We dug mother out
the day before.

It was a two-story house.

It went down
and it became a rubble.

NARRATOR: Some of the villagers have
no family left to care for them.

This man was found
collapsed in his home.


NARRATOR: Many villagers will move
away, for fear of landslides.

Those who stay
have nowhere else to go.

NARRATOR: Ang and the nurses
have raised just enough money

to call in a helicopter
for Seema.

A broken leg left untreated
could be fatal.

She and her father
have never flown before,

and this flight, through
the clouds, is a risky one.

This ambulance is one of Seema's
first rides in a vehicle.

She's never been to Kathmandu,
and now it's a city in crisis.

This is a military field
hospital set up by the Chinese.

One of the few available x-ray
machines in Nepal is here.

Surprisingly, Seema's bones
are completely intact.

NARRATOR: The stones that
were pinning down her leg

may have damaged a nerve.

NARRATOR: She can't move her
toes, and without treatment,

she could lose the use
of her leg for life.

As the aftershocks continue,
everyone is afraid

another large quake
will strike soon.

Earthquakes almost always
follow patterns.

These photos are from the last
big one here, in 1934.

It was at least an 8.0

that ruptured in an area
further to the east.

Roger Bilham believes this quake

is a repeat of one
that happened in 1833.

It ruptured in the same region
with similar impact.

This earthquake enables us

to reinterpret
all historical earthquakes,

and our only knowledge
of these earthquakes

is how people perceived them.

NARRATOR: Since there were
no seismic records in 1833,

Roger had to study
newspaper accounts

and travelers' journals.

From those descriptions,
he estimated the earthquake

had a magnitude of 7.8, similar
to the present-day quake.

Well, suddenly
we have an earthquake

that we know about numerically

which has just been felt
by a million people,

and those million people
have spoken to reporters

and we've now been able
to make a catalogue

of hundreds of accounts
for this earthquake.

And those accounts
can now be translated

into a much more precise
numerical evaluation

of historical earthquakes.

NARRATOR: That quake was followed
by a series of aftershocks

over two years.

But since 1833, enormous stress
has built up along the fault,

leading Roger to believe that
the 2015 earthquake

should've been larger.

The first thing we thought was,

"Gosh, this is smaller
than we expected."

NARRATOR: He expected a
magnitude eight or higher,

at least double the power
of the killer that just struck.

So how much energy is still
stored in the fault?

Scientists know that the plates
move at 18 millimeters a year.

In the 182 years since 1833,

they've moved
about three meters.

But in some places,
the faults are stuck,

and this lack of movement

creates a predictable amount
of strain.

John Galetzka is a geodesist

who measures changes
on the surface of the planet.

He can tell
how much of the strain

the 2015 earthquake released.

He's flying directly
to one of the places

where the two plates,

carrying India and Tibet,
are stuck.

33 kilometers to Dunche!

NARRATOR: He'll determine just
how much the locked plates,

20 kilometers below, lurched
forward during the quake.

If they didn't move enough,

there's more stress
to be released.

We'll get seismic data!

NARRATOR: GPS stations fixed
solidly to the earth's surface

have the answers.

GALETZKA: I'm just going
to demonstrate for you

how strong the monument is here.

So really, it's anchored
into the earth here,

about a meter and a half
or two meters.

Glued in.


NARRATOR: This is one of
over 50 active GPS stations

placed across the Himalayan arc
of Nepal

measuring minute movements
of the Earth.

GPS satellites broadcast
microwave signals

to stations on the ground.

The GPS stations
are so sensitive,

they can detect shifts
as small as a millimeter.

Data reveals
the earthquake released

only half of the stress
that's accumulated since 1833.

This station moved to the south
about a meter and a half.

So just to demonstrate,

this station was
about right here ten days ago,

and then the earthquake

the earthquake happened,
so seismic waves,

and then seismic waves
and the tectonic movement,

the plate shifting,

and then the antenna settled
to where it is right now.

NARRATOR: This GPS station and others
didn't move as much as expected

because the earthquake
only ruptured

the lower, deeper part
of the fault.

This means a portion
of the fault remains loaded

with pent-up energy
for future earthquakes.

JOHN ELLIOTT: This was a very
big earthquake in Nepal,

but it's not the biggest
that can happen.

It hasn't relieved
all the pressure

across this large faulting area.

There are other bits
of the fault

that still need to break
in the future.

NARRATOR: Does this mean
there's more to come?

This earthquake battery
didn't run all the way down.

It's still partially charged,

leaving a reservoir of stress
to be tapped by future quakes.

A bigger concern is that
there are places along the fault

where no stress was released
by this earthquake.

Recent earthquakes
have relieved built-up stress

to the east in India,

and also to the west
in Pakistan.

But there's an area in between,
to the west of Nepal,

that's locked.

This earthquake didn't cause it
to budge even a bit.

It's a time bomb
waiting to erupt,

where no movement has occurred
for centuries.


all the strain built up
has not been released

and it's still down there,

which means that there is some
danger of further earthquakes

to the west of the fault,
which still remains locked,

and that's a problem.

Like a sleeping giant,

the west of Nepal
has at least ten meters

of built-up slip
stored beneath it.

It last slipped in 1505.

That's 500 years of coiled up
potential energy

ready to spring.

You know, it's really scary.

We know earthquakes

as big as 8.6 have occurred
in the Himalayas.

There is no reason why one
with that magnitude

could not occur
in the next ten years

or the next ten minutes.

NARRATOR: The challenge is
to now prepare the people

for this potential catastrophe.

It'll be 16 times bigger
than the 2015 earthquake.

Day five.

Just as rescuers
are losing hope,

they discover a trapped victim
still alive.

Volunteers from the Los Angeles
County Fire Department

have arrived
to help the local police.

ANDREW OLVERA: We were told
that there's voices heard

and a void space.

We have a search reconnaissance
team with us right now,

and we're going to go ahead

and have the rescue squad
come in

and help extricate that victim
out of the hole.

Concrete rescue saws

can cut through what's left
of an eight-story building.

Nepal police force inspector
Laxman Bahadur Basnet

risks his life to crawl
under the tons of rubble.

NARRATOR: They've found a 15-year-old
boy entombed in complete darkness.

They battle for five hours
to free him.


PEMBA LAMA (translated):
I was eating,

and then the earthquake hit.

When I was trying to get out,

the walls broke into pieces
and fell on top of me.

I was unconscious at first,

and then I thought
it was just a nightmare.

It's what we call an entombment.

So, he wasn't specifically

but what he was
was inside of a box,

a box with heavy concrete
all around him.


Pemba Lama has emerged

into a world
dramatically altered.

Earthquakes have the power
to instantly reshape the land.

Their most obvious effect
is a sudden slip

to one side or another.

What's less obvious

is that the earth can move
vertically, too.

Geophysicist John Elliott
figures out just how much

using satellite data.

Using this data,

we can measure
precisely how much

the earth has moved up and down.

Each of these is a contour,

but instead of telling you
how high the mountains are,

it tells you how much higher,
how much they grew,

or how much they reduced
in size.

Each of these is
a ten-centimeter contour...

we have ten of them...

and this area beneath Kathmandu

actually uplifted
by about a meter,

whereas these high mountains
north of Kathmandu

actually went down
about 70 centimeters.

NARRATOR: The earthquake caused
Kathmandu to rise three feet up.

Mount Everest, on the other
hand, sank by about an inch.

But it was the side-to-side

on a ridge above Base Camp
that triggered the avalanche.

Ultimately, it killed 20 people
and injured 120.

But the avalanche only deposited
a couple inches of snow in camp.

NARRATOR: So what caused the
death and destruction here?

This wasn't a normal avalanche.

Some of these tents have thick
steel poles.

We later learned that when
those things are hit

by a 300 mile-per-hour-plus

they become lethal missiles.

NARRATOR: Scientists in Davos,
Switzerland, simulate

the physical forces
behind avalanches.

But they've never modeled one
this extreme.

Yves Buhler and Perry Bartelt
want to figure out

exactly how much ice was
dislodged above Base Camp

by the earthquake.

David Breashears was able to get
them close-up photos

of the ridgeline
where the ice calved off.

I commissioned a helicopter

to fly directly above Base Camp.

And I flew back and forth
with the door open.

Because David is doing

so high-resolution shots
we can zoom in.

So this is what we identified
as the main release mass.

NARRATOR: The chunks of ice that
the earthquake tremors shook

off the ridge above Base Camp

were akin to 100,000 cars
plummeting toward camp.

The avalanche took 60 seconds
to descend nearly 3,000 feet,

reaching speeds
of up to 157 miles an hour.

The impact of the ice mass
hitting ground zero

detonated a force comparable
to a bomb blast.

One powder cloud jet managed
to push its way through

and it shot it directly towards
the Base Camp.

NARRATOR: Upon impact, the
avalanche kicks up an envelope,

called a "powder cloud,"
one percent snow and 99% air.

And that's what we
observed in the video.

That it was like ejected
into the air.

NARRATOR: This powder cloud
reached a height of 650 feet.

And just in front of that cloud

blasts an invisible,
but deadly, pressure wave.

The Swiss team determined that
the force of the pressure wave,

indicated here in red,

was enough to flatten
a wooden building.

Many climbers were killed
by a violent blast of air

moving at more
than 100 miles per hour.

The color is the pressure,

so the pressure that people

when they were there.

And red means the limit where
a person gets smashed

against rocks.

NARRATOR: Climber Paul Devaney
photographed huge barrels

that were blown from the camp

several hundred meters across
the glacier into a gully.

DEVANEY: It's a scene of
pretty surreal devastation.

It's like a plane crash
or something.

It's hard to imagine
what's just happened here

in the last few hours.


NARRATOR: At the same moment,
nearly 100 miles away,

a similar, and even more deadly,

hit the village of Langtang.

David Breashears photomapped
the devastation.

BREASHEARS: When I flew in
that helicopter up that valley

and over Langtang,
I really had a hard time

getting my head around
what I was seeing.

An entire village was gone.


Thousands of trees, trees this
big around, were flattened,

stripped of their bark
and branches.

It looked like what we had seen
after the volcanic eruption

of Mount Saint Helens.

NARRATOR: David stood at the
place where he had taken a photo

of Langtang in 2012
and shot an exact match.

Over 400 people and 116 homes
were lost in an instant.

How could such a colossal event
come to pass

without a trace of warning
for those below?


NARRATOR: In the village above
Langtang, a similar event occurred.

BREASHEARS: This would've
been a group of people

who would've gotten out of their
buildings and said, "It's okay."

And then they would have no idea

what was coming from
10,000 feet above them.

They had survived an earthquake,

but out of the clouds came
something even more powerful.

Look, look, look!

Oh, my God!

NARRATOR: The earthquake
unleashed multiple avalanches

onto Langtang Valley,

one of the most popular
trekking routes in Nepal.

BARTELT: It took the avalanche
about 80 seconds after release

to get down to the valley

And the avalanche reaches
tremendous speeds.

And shot out almost directly
into the air above Langtang

and then plummeted
into the valley bottom.

People just below Langtang,

in the narrow valley, suffered
from pummeling rocks and debris.

Here comes more!

NARRATOR: The cloud could
be seen for miles.

Everyone was running

from plummeting boulders
and landslides.

And it was breaking everywhere,

and it was breaking in places
you couldn't see.

It was in the clouds.

And you could hear it coming
from 2,000, 3,000 meters above.

NARRATOR: Austin Lord
captured this footage

in a village two miles
below Langtang.

LORD: You weren't sure if all of
a sudden something would burst

through the clouds that you
couldn't run from.

Here comes another tremor!

Splinters coming from the sky,

small rock debris coming
from the sky.

The houses that were directly

in the path of the core had
absolutely no chance.

They were demolished
and blown away immediately.

BREASHEARS: It looks like what you
see when one of these tornadoes

of epic proportion just runs
right through a place.

This was a mega-avalanche.

A chunk of ice larger than
the Empire State Building

fell three times farther
than the Everest avalanche...

more than 10,000
vertical feet...

reaching a speed
of 225 miles per hour

before hitting the village
of Langtang.

That would be ten times the most
extreme avalanche

we would have in Switzerland.

And that's just
a very, very extreme

and unique avalanche event.

NARRATOR: Austin Lord was among
over 300 survivors stranded

in Langtang Valley,
unable to get out

due to landslides and avalanches
blocking the way.

LORD: And then I looked upslope,
where Langtang should've been,

and you could see that Langtang
was just... gone.

And I was standing with two
or three other people

who realized it at
the same time as me,

locals whose families are
located above and below

and in Langtang,
and it was heartstopping.

Local people were seeing each
other, realizing who was gone,

who was still there,

people coming down saying
to the people coming up:

"There's no one.

This is... this is everyone."

And just people collapsing,
just people breaking and melting

and children wailing.

That was the hardest part.

wandering down this trail

with debris on both sides of us

and we saw a man coming up
the trail towards us.

And he'd come back up the
valley, having evacuated it,

to look for his wife,

and along with the army
search team,

he had found her body
ten minutes earlier.

The earth shook.

10,000 feet above him
the ice fell.

And in the blink of an eye
his life had changed.

He had no home, he had no wife,

and he had only the 600 rupees
in his pocket

and that was six dollars.

And that's something
that I will never forget.

NARRATOR: 17 days after the main
shock, huge tremors rock Nepal again.

Cameras in parliament
capture the panic.

About a minute ago,

there was a very violent

We don't know where it was,

probably about 20 or 30
kilometers from Kathmandu.

And it set the whole valley

just like it did
in the main earthquake.

Everyone was absolutely

NARRATOR: Could this be a
big aftershock, as in 1833?

Or the big one
from the west of Nepal

that they've been dreading?

Rarely does a seismologist
get to be part

of an earthquake he is studying.

I think it's still moving!

It is still moving.

Good grief!

To see people with their arms

wondering what was going
to hit them

even though there was
nothing above them.

Only trees and birds.

People don't do that unless
they've just recovered

from an even worse shock,
which of course was 16 days ago,

the main shock.

This is what happened in 1833.

About two weeks later,
there was a large aftershock

that was felt in India.

And I'm sure this one
would have been, too.

NARRATOR: Roger will be able to
determine if it's an aftershock

or a new earthquake
in a matter of minutes.

I've dialed up the USGS
earthquake page

and I'm sitting here waiting for
a dot to appear on the map

to tell me how big
and exactly where it was.

It takes 24 minutes
for a seismic wave to cross

from one side of the Earth
to the other.

And what we're waiting for are
the seismic waves to hit

those distant seismometers
and then for their data

to be transmitted via satellite
at the speed of light.

Keep going for 1.5 kilometers.

Yeah, go down here.

And these data arrive
in Golden, Colorado,

and then they're processed
to find out how big

and exactly where and how deep
the earthquake was.

The shaking is intense enough

to send people running
out of buildings,

bodies of water
sloshed in waves.


That was enormous!

It's a 7.4.

My goodness!

So, this is only
a little bit smaller

than the main shock.

No wonder people were scared.

The main shock was 7.8.

This was 7.4, which means
the energy released

is four times less,

but to the terrified inhabitants
of this city,

the impact was just the same.

(woman screaming,
people shouting)

BILHAM: It was 83
kilometers from Kathmandu.

It was near Mount Everest.

So that will have produced an
enormous amount of avalanches.

It's really tragic.

NARRATOR: Roger concludes
it's an aftershock

to the east of the main shock,

a section of the fault that
hadn't moved enough

and was catching up,

releasing as much energy
as a 25-megaton bomb.

This aftershock was big enough

to be a main shock
in its own right.

Let's go and talk
to the survey department.

It was magnitude 7.4!

NARRATOR: When an earthquake
strikes, scientists need to know

not only the magnitude
at the epicenter,

but also the intensity of the
shaking felt in each village.

Roger and David Breashears fly
over the region.

Roger's mission was

by looking at buildings and
the way that they had held up,

he could determine
the shake intensity.

It's the velocity

at what the surface of the earth
was moving at and the frequency.

There were no instruments in
these mountain areas

to measure the shake intensity,

but Roger knows
how to determine that

by what happened to buildings.

BILHAM: We needed to
get out here quickly

because in the days following
an earthquake,

people already start
cleaning up.

You don't leave a pile of rubble
in your front yard.

So, we lose some of the clues
that we need

to understand why
the buildings fell down.

They maneuver close to villages

so David can shoot
high-resolution photos.

BREASHEARS: We'll be able
to zoom in on those images

and even look at such fine
detail that you can just see

bricks or stacked fieldstone

and from that Roger was able
to make a determination.

Using a shake intensity scale,

Roger puts a value
between one and ten

on the observable damage
produced in each village.

If crockery falls off a shelf,
it's intensity six.

Poorly made buildings will
partially collapse at seven,

but they'll flatten at eight.

Total destruction would result
from intensity ten.

This scale informs engineers

for the next big quake.

Over 770,000 buildings were
either damaged or flattened

by this earthquake.

Why did some collapse
and others survive?

There's a clue in the heart
of Kathmandu.

Durbar Square experienced
intensity seven shaking.

It's a World Heritage site
turned to rubble.

But the dust-laden debris,

dating back to the sixth
century, holds a secret.

KAI WEISE: The big earthquakes
only come every 80 to 100 years

so there's a generation gap
very often

and then they have to relearn

the need to protect themselves.

After the last earthquake,
I mean,

we were still reconstructing
after 80 years.

Initially, it was just a shock
to see on the news

all these images,
and it's just unbelievable.

But then it slowly sinks in and
you sort of have to accept

the fact, you know, what kind of
destruction there has been.

NARRATOR: Coronations of kings
have taken place here...

five acres and ten courtyards,

dominated by the white
19th century portion

of the neoclassical
Hanuman Dhoka palace,

the newer wing of the original
palace, built in the 1770s.

The palace presides

over some of Kathmandu's
oldest living temples.

WEISE: Most of these temples
are still being used

and they have religious value as
well as purely cultural value.

NARRATOR: This undated stone
image of Kal Bhairav,

the Hindu god of justice,
has survived many quakes.

Out here, we see that two of
these tiered temples

on these platforms
have totally collapsed.

Very clearly these two temples
sort of create

this whole space here,

which is a part of the identity
of the city.

They went in with heavy
machinery to clear it up

and the problem is heavy
machinery impacts

all of the material that could
be reused later on.

But we've tried to salvage

as much of this material
as possible.

There are all these different

and I think they have been mixed
up between the temples

and that will be a major

just trying to figure out

where these different elements
came from.

NARRATOR: Damage assessment
of heritage buildings

requires detective work.

The skin of a centuries-old
palace can hide

the true structure within.

Why is the old palace
still intact,

while the newer, white palace
walls must be shored up?

So we were scared

that that would
actually collapse,

and if it would, it would bring
that whole corner down...

NARRATOR: The white plaster-faced
building is failing.

Both are brick construction

and have suffered
through past earthquakes.

Randolph Langenbach is
a conservation architect.

He travels to earthquake zones
to find out what makes

some traditional buildings

NARRATOR: Randolph finds timber
hidden within the brick façade.

It's not just a single timber,
but it essentially is

like placing a ladder
onto the wall.

In other words this cross piece
is very much a part

of the system.

WIESE: So you have the beams
on the inside and outside.

And then it's held together with
this one, which goes through,

so that it basically ties
the wall together.

You know what's interesting?

You know what I realized?

It's a frame,
timberframe structure.

Yeah, yeah, yeah,
you can see the woodwork

going all the way through
the ground floor.

And in one corner,
probably one of...

Vertical woodwork.

Yes, yes, yes!

And it's tied together.

Then it answers the question.

It answers why it behaved...

it had a different
sympathetic motion.

Because this is
a frame structure.

It's actually more flexible.

And it's rocking back and forth
essentially as a solid unit.

So it can't travel with this

and it broke everything up
around it, but it stayed intact.

NARRATOR: It's the timbers
hidden within the brick masonry

that laces the older palace
together, holding it firm

yet elastic enough to withstand
an earthquake.

So here the beautiful thing is

that they also started
to put in ornamentation

within the latticework.

Up here you can see these beams.

They're tied
with the wooden pegs.

And now that is to hold
the brickwork.

This is really traditional
earthquake technology.

NARRATOR: This combination of
timberlacing with brick was not used

in the more recently constructed
white palace,

which is on the verge
of collapse.

WIESE: They had to develop this
system of combining the wood

with the brickwork

and it took centuries
for them to develop this

and it became the traditional
system of construction,

but then later on they forgot
these lessons.

NARRATOR: For the two million
Nepalis faced with rebuilding

their homes, this critical
lesson in protecting themselves

must be relearned.

But wood in remote villages
is often not available.

So how can the millions
who live in fieldstone villages

build earthquake-resistant

BILHAM: The village construction
practices have to use

indigenous materials.

They don't have access
to cement.

Bricks are not available.

Instead they use local stones

and they do not adhere to the
cement that they have to use,

which is mud.

And mud is incredibly weak.

Some of the structures that
survived have wooden tie beams

around the walls that have held
them together.

NARRATOR: One of the
hardest-hit districts,

close to the epicenter,
is Dhading.

Randolph is on a mission
to rebuild a home

that is earthquake-resistant,
using local materials.

The right consistency of mud,
hardware wire and stone

is all that's needed
for a safe home

made in the traditional style
for much of Nepal.

The wire was purchased

at the nearest hardware store
and carried in.

One thing they had

was wire fencing for keeping
the animals in.

The idea came to my mind.

Well, why not use the wire?

Randolph's idea is to install

a reinforcing element
he calls "gabion bands"

right into the masonry walls,

just like
the Hanuman Dhoka Palace.

Gabion is a wire cage
filled with rocks.

We need 22 feet.

NARRATOR: Structural engineer Dipendra
Gautam trains local stonemasons

to use gabion bands as
a substitute for timber bands.

NARRATOR: The homes in this
region suffered intense damage.

Ninety percent have
to be rebuilt.

Add a simple band that ties
the walls together,

even with bicycle tubes,
and the building might hold.

LANGENBACH: They needed to have some
tensile reinforcement in the walls,

and the traditional way of doing
that was in the series of bands.

NARRATOR: Each wire band has a
layer of stone and mud mortar

placed onto it.

This is wrapped into a cage and
all four walls of the building

are tied together to form what
engineers call a ring beam.

LANGENBACH: The band seemed to be
something that could be hand-carried in.

It could be understood by people
in a short explanation.

NARRATOR: This will be home for a
man named Ram, who is a Dalit,

the lowest caste in Nepal.

His father committed suicide
last year,

and the earthquake then
destroyed Ram's home.


(boy laughing)

The timberlacing that we saw

in the 18th century part
of the Hanuman Dhoka palace...

and those parts have survived
almost entirely intact...

is a way of giving
tensile strength to the wall.

And this is a basic
engineering concept.

This is not distant at all from
what engineers say is needed.

NARRATOR: We know another
earthquake will come,

maybe in two years
as an aftershock,

or maybe the big one will
rupture from the west of Nepal.

But Ram is now better prepared.

This earthquake took nearly
9,000 lives, but Seema Tamang...

who was buried under the rubble
of her home for 24 hours...

survived the odds.

How do you feel today?

(translator speaking)

NARRATOR: She had little hope of
recovering the use of her leg.

But she wants to go back
to school

and get there
on her own two feet.

Having lived
through a megaquake,

the first of their lifetimes,

are the people of Nepal
now more prepared to face

their seismic future?

BILHAM: This earthquake acted
as a kind of a Rosetta stone,

interpreting all previous
earthquakes, and I'm sure

we are going to see
enormous headway

as a result of this earthquake.

Not only from the seismological
point of view,

but from the philanthropic
point of view,

and earthquake engineering,

and what kind
of buildings we need

to survive the next earthquake.

NARRATOR: The pent-up tectonic
stress miles beneath the Himalayas

continues to build.

Can you lift your toe?

This one?

And now this one.

Straighten the good one.


Oh, look at that!

They both go straight.

So that means this quadriceps
muscle is working,

which is good.

Living with large earthquakes

is a reality for the people
of the Himalaya,

since they happen in Nepal
about every hundred years.

Thankfully, the earthquake
wasn't that big.

Tragic, yes.

But, let's see if we can't learn
now from this earthquake

to help us get prepared for that
next big one, whenever it comes.

This is fantastic!

Come back here, sweetie.

I'm so happy for you.

This is great!

This is really good.

NARRATOR: Nepal is a nation
that will walk again,

because this earthquake not only
tells a story about the past,

but about the inevitable
seismic perils

that will come in the future.

The investigation
continues online,

This NOVA program
is available on DVD.

NOVA is also available
for download on iTunes.