00:00:05.130 --> 00:00:08.320
Deep below boiling mud
pools, a tectonic

00:00:08.320 --> 00:00:09.720
battle is under way.

00:00:12.504 --> 00:00:16.980
A fiery confrontation fought at
temperature as high 1,000

00:00:16.980 --> 00:00:18.230
degrees Celsius.

00:00:24.830 --> 00:00:29.288
The Tarawara event would be 5
to 10 times the size of the

00:00:29.288 --> 00:00:30.820
Mount St. Helens event.

00:00:30.820 --> 00:00:32.170
Ultimately, you would
have been killed

00:00:32.170 --> 00:00:33.860
if you're this close.

00:00:33.860 --> 00:00:37.350
On the surface are the scars of
that collision, venerated

00:00:37.350 --> 00:00:39.946
in myth and ritual.

00:00:39.946 --> 00:00:47.015
[NATIVE CHANTING]

00:00:47.015 --> 00:00:50.780
To the people who live around
the Pacific Rim, the threat is

00:00:50.780 --> 00:00:52.030
a constant.

00:00:59.040 --> 00:01:01.890
The Rim is the front line in
the subterranean struggle

00:01:01.890 --> 00:01:05.014
where the Earth as we know
it can suddenly change.

00:01:11.777 --> 00:01:18.270
[SHOUTING IN JAPANESE]

00:01:18.270 --> 00:01:21.880
From New Zealand to Japan, this
region is one of the most

00:01:21.880 --> 00:01:23.770
hazardous on the planet.

00:01:23.770 --> 00:01:26.286
But with destruction,
comes creation.

00:01:32.530 --> 00:01:36.140
High in the southern Alps of New
Zealand, we see new lands

00:01:36.140 --> 00:01:37.250
being born.

00:01:37.250 --> 00:01:41.250
And explore the dynamic forces
that are reshaping the face of

00:01:41.250 --> 00:01:42.700
the world we live on.

00:01:53.870 --> 00:01:57.260
An epic journey along the
Pacific Rim with Canadian

00:01:57.260 --> 00:02:00.440
geologist, Professor Nick Eyles
from the University of

00:02:00.440 --> 00:02:02.030
Toronto as our guide.

00:02:31.960 --> 00:02:34.480
New Zealand is a latecomer
in the geologic

00:02:34.480 --> 00:02:36.360
history of our planet.

00:02:36.360 --> 00:02:39.450
Submerged for much of its
history, it's scattered

00:02:39.450 --> 00:02:42.715
islands will one day fill out
to form a new continent.

00:02:45.550 --> 00:02:47.440
But what's the mechanism?

00:02:47.440 --> 00:02:49.520
What are the forces at play?

00:02:58.560 --> 00:03:02.090
White Island, a hyperactive
volcano on the edge of the

00:03:02.090 --> 00:03:06.040
Rim, just off New Zealand's east
coast, provides a ring

00:03:06.040 --> 00:03:10.207
side view of the convulsive
battle between ocean and land.

00:03:26.111 --> 00:03:29.266
Like a scene out of Dante's
Inferno, isn't it?

00:03:29.266 --> 00:03:31.520
It's impressive, isn't it?

00:03:31.520 --> 00:03:34.166
Come this way.

00:03:34.166 --> 00:03:35.416
Like hell.

00:03:40.710 --> 00:03:44.932
Well, do you have an idea of
how frequent it erupts?

00:03:44.932 --> 00:03:47.030
Well, it's been incredibly
active really.

00:03:47.030 --> 00:03:51.840
So I imagine, on average, this
is active about every seven

00:03:51.840 --> 00:03:53.150
years, something of the order.

00:03:56.210 --> 00:03:59.700
This level of activity has
made the volcano a living

00:03:59.700 --> 00:04:03.450
laboratory where scientists,
such as Hamish Campbell with

00:04:03.450 --> 00:04:06.380
GNS Science, pay close
attention to

00:04:06.380 --> 00:04:09.140
it's fiery inner life.

00:04:09.140 --> 00:04:14.060
We monitor volcanoes like this
in a number of ways, where

00:04:14.060 --> 00:04:21.720
we're chemically, seismically,
and also we use fancy

00:04:21.720 --> 00:04:24.370
satellite-based surveying,
geodetics--

00:04:24.370 --> 00:04:25.650
To see if there's any swelling
involvement.

00:04:25.650 --> 00:04:28.430
Yeah, to see if there's
any sort of movement.

00:04:28.430 --> 00:04:31.660
That the whole system is
inflating, or deflating,

00:04:31.660 --> 00:04:33.170
changing shape.

00:04:33.170 --> 00:04:35.705
And we're doing that on a,
pretty much, a daily basis.

00:04:35.705 --> 00:04:37.960
And we've got instruments
all around the crater.

00:04:40.880 --> 00:04:41.620
So what's all this rubble?

00:04:41.620 --> 00:04:44.640
Is this left over from
the last eruption?

00:04:44.640 --> 00:04:47.960
Looks very jumbled
up, doesn't it?

00:04:47.960 --> 00:04:50.830
See those blocky lava
flows over there?

00:04:55.210 --> 00:04:59.670
It's slopes reveal a violent
and chaotic past.

00:04:59.670 --> 00:05:01.965
A jumble of fallen
rock and ash.

00:05:12.965 --> 00:05:16.670
So you can imagine it might be
a really big eruption soon,

00:05:16.670 --> 00:05:19.750
and this material might actually
get either blown

00:05:19.750 --> 00:05:25.050
completely away, or actually
capped by fresh lava.

00:05:25.050 --> 00:05:28.710
The debris, broken by the sudden
shock of an explosive

00:05:28.710 --> 00:05:32.470
eruption, is referred
to as pyroclastic,

00:05:32.470 --> 00:05:34.210
meaning broken by fire.

00:05:36.960 --> 00:05:41.350
All these deposits are pretty
much at the angle of repose,

00:05:41.350 --> 00:05:42.670
and they're at the
tipping point.

00:05:42.670 --> 00:05:45.700
It doesn't take much
inflation, or--

00:05:45.700 --> 00:05:46.270
A little earthquake.

00:05:46.270 --> 00:05:48.490
--a little earthquake, and
you're in trouble.

00:05:48.490 --> 00:05:50.650
The stuff will be mobilized
and head downstream.

00:05:50.650 --> 00:05:52.180
What happened here
with this part?

00:05:52.180 --> 00:05:54.090
The rim has gone out
into the ocean.

00:05:54.090 --> 00:05:54.400
That's right.

00:05:54.400 --> 00:05:59.430
This is a classic sector
collapse structure.

00:05:59.430 --> 00:06:00.390
And it's amazing to see.

00:06:00.390 --> 00:06:02.240
It's rather like Mount
St. Helens.

00:06:02.240 --> 00:06:05.630
It's pretty much what happened
there in 1980, where the whole

00:06:05.630 --> 00:06:07.300
flank of the mountain
just goes, pshew.

00:06:07.300 --> 00:06:09.840
Which is why the volcanoes are
so dangerous, because instead

00:06:09.840 --> 00:06:11.860
of going up, it's
vented sideways.

00:06:11.860 --> 00:06:13.100
That's right, yeah.

00:06:13.100 --> 00:06:15.730
I mean, I actually think
of volcanoes as

00:06:15.730 --> 00:06:17.390
just natural chimneys.

00:06:17.390 --> 00:06:21.230
They're just a great pile of
debris that spattered out, and

00:06:21.230 --> 00:06:22.480
they are inherently unstable.

00:06:27.880 --> 00:06:31.450
White Island, as with all of New
Zealand, sits right on the

00:06:31.450 --> 00:06:35.720
Rim, at the junction of the
Pacific and Australian plates.

00:06:35.720 --> 00:06:39.320
It's a collision area where the
floor of the Pacific Ocean

00:06:39.320 --> 00:06:42.400
dives deep below the Australian
plate, in what is

00:06:42.400 --> 00:06:46.660
called a subduction zone.

00:06:46.660 --> 00:06:50.430
The sea floor is buckled and
pulled down into deep

00:06:50.430 --> 00:06:54.480
trenches, and the friction
triggers powerful earthquakes,

00:06:54.480 --> 00:06:58.210
as the Pacific plate
is slowly consumed.

00:06:58.210 --> 00:07:02.590
Even here, magma flows from
underwater volcanoes, as rocks

00:07:02.590 --> 00:07:04.046
are melted and recycled.

00:07:11.720 --> 00:07:15.480
White Island is one of a chain
of volcanoes that includes the

00:07:15.480 --> 00:07:16.730
notorious Tarawara.

00:07:20.890 --> 00:07:23.560
That was quite a bumpy flight.

00:07:23.560 --> 00:07:26.680
But it's worth it because we're
right on the Pacific Rim

00:07:26.680 --> 00:07:28.090
now, aren't we?

00:07:28.090 --> 00:07:28.860
We are.

00:07:28.860 --> 00:07:32.150
This is the Pacific Ring
of Fire at it's best.

00:07:32.150 --> 00:07:34.870
There's not many places where
you can see it so graphically.

00:07:34.870 --> 00:07:37.880
So were literally walking to
the edge of the Australian

00:07:37.880 --> 00:07:41.780
plate, and right in front of
us is the Pacific plate.

00:07:41.780 --> 00:07:43.590
Well, we're not quite
going that far.

00:07:43.590 --> 00:07:46.230
I mean, we really are entirely
on the Australian plate here,

00:07:46.230 --> 00:07:48.820
but this is where we feel the
effects of the down-going

00:07:48.820 --> 00:07:51.690
Pacific plate.

00:07:51.690 --> 00:07:55.350
Plate's going down, starting
to melt from the

00:07:55.350 --> 00:07:58.794
friction and heat.

00:07:58.794 --> 00:08:02.230
All the magma's coming back
right underneath these aligned

00:08:02.230 --> 00:08:04.290
volcanoes, all the
way through here.

00:08:04.290 --> 00:08:05.650
That's right.

00:08:05.650 --> 00:08:07.450
I like to say there's a volcano
probably about every

00:08:07.450 --> 00:08:10.260
40 to 60 kilometers,
all the way up.

00:08:10.260 --> 00:08:13.330
Now we're looking down at some
very impressive volcanic ash

00:08:13.330 --> 00:08:14.090
layers, aren't we?

00:08:14.090 --> 00:08:14.580
We are.

00:08:14.580 --> 00:08:16.650
This is absolutely
spectacular.

00:08:16.650 --> 00:08:22.090
This is a fissure, a rift,
that's formed as a product of

00:08:22.090 --> 00:08:25.880
the eruption in 1886 of
Mount Tarawara that

00:08:25.880 --> 00:08:27.620
we're standing on now.

00:08:27.620 --> 00:08:30.060
And you can actually see,
it's very revealing.

00:08:30.060 --> 00:08:35.970
The eruption's literally cut
through underlying pyroclastic

00:08:35.970 --> 00:08:40.030
deposits associated with the
penultimate eruption of Mount

00:08:40.030 --> 00:08:43.929
Tarawara, which was in 1314
AD, or thereabouts.

00:08:43.929 --> 00:08:48.060
So those pale layers,
well-layered, really, the

00:08:48.060 --> 00:08:50.610
tephra, ash, if you
like, that had

00:08:50.610 --> 00:08:52.500
accumulated in that eruption.

00:08:52.500 --> 00:08:55.680
And then in 1886,
this incredible

00:08:55.680 --> 00:08:57.430
eruption took place.

00:08:57.430 --> 00:09:01.700
It only lasted about four hours,
and it produced these

00:09:01.700 --> 00:09:07.130
dark bright red, grey, black
pyroclastic deposits that we

00:09:07.130 --> 00:09:08.630
see sitting on top of
the white layer.

00:09:12.518 --> 00:09:14.825
Here we are, on the south
side of the mountain.

00:09:14.825 --> 00:09:18.070
Was the eruption very
directional?

00:09:18.070 --> 00:09:18.980
Which one?

00:09:18.980 --> 00:09:19.570
Tarawara?

00:09:19.570 --> 00:09:20.680
Tarawara eruption.

00:09:20.680 --> 00:09:25.030
Tarawara was quite a strong
southerly, southwesterly

00:09:25.030 --> 00:09:29.860
blowing, so a lot of the
material blew to the north,

00:09:29.860 --> 00:09:31.180
600 kilometers--

00:09:31.180 --> 00:09:34.180
David Lowe has a particular
interest in Tarawara.

00:09:34.180 --> 00:09:38.020
He's a volcanologist with the
University of Waikato.

00:09:38.020 --> 00:09:42.066
So what's the furthest away from
New Zealand that you can

00:09:42.066 --> 00:09:47.460
pick up a ash layer in the
marine record and say, yeah,

00:09:47.460 --> 00:09:48.730
that's from New Zealand?

00:09:48.730 --> 00:09:49.730
Of any eruption?

00:09:49.730 --> 00:09:51.000
Yeah.

00:09:51.000 --> 00:09:55.820
Um, pretty much, South
America, they reckon.

00:09:55.820 --> 00:09:58.980
Each of these layers records
an eruption.

00:09:58.980 --> 00:10:03.230
By studying the location and
depth of ash, or tephra, Lowe

00:10:03.230 --> 00:10:07.380
has constructed a volcanic
timeline dating back close to

00:10:07.380 --> 00:10:08.630
10,000 years.

00:10:17.460 --> 00:10:19.930
If we'd been here during an
eruption, looking at the

00:10:19.930 --> 00:10:22.250
volcano, what would this have
looked like during the

00:10:22.250 --> 00:10:24.190
progress of that eruption?

00:10:24.190 --> 00:10:24.520
Ah.

00:10:24.520 --> 00:10:27.510
It would've been spectacular,
and very dangerous.

00:10:27.510 --> 00:10:29.280
Ultimately, you would
have been killed if

00:10:29.280 --> 00:10:30.530
you were this close.

00:10:35.780 --> 00:10:41.400
The 1886 eruption happened
around midnight on June 10.

00:10:41.400 --> 00:10:46.420
Without warning, the upper part
of the volcano exploded,

00:10:46.420 --> 00:10:50.120
burying the landscape and
surrounding villages under a

00:10:50.120 --> 00:10:56.860
thick blanket of pulverized
rock, incinerating everything

00:10:56.860 --> 00:10:58.110
in it's path.

00:11:01.130 --> 00:11:03.980
The scale of destruction
was immense.

00:11:03.980 --> 00:11:05.740
Whole forests were torn
up and burned.

00:11:14.060 --> 00:11:17.520
More than 100 people died
that night, most

00:11:17.520 --> 00:11:18.770
of them were Maori.

00:11:21.260 --> 00:11:23.930
The slopes also provide evidence
of the earlier

00:11:23.930 --> 00:11:28.820
eruption in 1314, some 70 years
after New Zealand was

00:11:28.820 --> 00:11:31.090
first settled by the Maori.

00:11:31.090 --> 00:11:35.230
Charred tree trunks encased in
ash, a stark reminder of the

00:11:35.230 --> 00:11:39.210
heat and ferocity
of the eruption.

00:11:39.210 --> 00:11:42.880
The Tarawara eruption coincides
approximately with

00:11:42.880 --> 00:11:46.880
the time of the arrival of the
first Polynesian settlers.

00:11:46.880 --> 00:11:50.800
So anybody living here would
have witnessed the eruption,

00:11:50.800 --> 00:11:54.260
and certainly those on the
coast, very sparse, we presume

00:11:54.260 --> 00:11:57.065
in those early days, they would
have seen the eruption

00:11:57.065 --> 00:11:59.546
and the impact as well.

00:11:59.546 --> 00:12:16.690
[NATIVE CHANTING]

00:12:16.690 --> 00:12:21.480
Maori legends speak of fired
gods, ahi tepia, and how their

00:12:21.480 --> 00:12:24.140
land was the gift
of the ocean.

00:12:24.140 --> 00:12:27.980
Their rituals venerate the
powers of ocean and volcano.

00:12:27.980 --> 00:12:31.480
The dancers embodying the
strength of tectonic forces.

00:12:37.540 --> 00:12:42.070
The legacy of the most recent
Tarawara eruption may be

00:12:42.070 --> 00:12:45.330
etched in the landscape, but
nothing can prepare this

00:12:45.330 --> 00:12:49.510
region for its future and the
enormity of the geological

00:12:49.510 --> 00:12:53.870
upheaval it will inevitably
one day face.

00:12:53.870 --> 00:12:58.490
Tarawara lies in the epicenter
of an ancient crater, or

00:12:58.490 --> 00:13:02.920
caldera, some 30 kilometers
across formed by the massive

00:13:02.920 --> 00:13:05.900
explosion of a super volcano.

00:13:05.900 --> 00:13:10.520
The eruption left a vast pit
that is now dotted with lakes

00:13:10.520 --> 00:13:13.820
and other smaller
stratovolcanoes.

00:13:13.820 --> 00:13:18.420
Similarly, the tranquil waters
of nearby Lake Taupo hide the

00:13:18.420 --> 00:13:21.550
scars of another super-scale
event.

00:13:21.550 --> 00:13:25.740
The eruption, the largest on the
planet in the last 70,000

00:13:25.740 --> 00:13:29.480
years, buried the entire
North Island under

00:13:29.480 --> 00:13:31.215
200 meters of ash.

00:13:33.930 --> 00:13:36.620
Dramatic as they are,
volcanoes are

00:13:36.620 --> 00:13:38.610
not the only threat.

00:13:38.610 --> 00:13:44.810
New Zealanders live with another
deadly tectonic force,

00:13:44.810 --> 00:13:46.060
earthquakes.

00:13:50.110 --> 00:13:53.870
The picturesque landscape
conceals a seismic grid, a

00:13:53.870 --> 00:13:56.440
network of hidden faults.

00:13:56.440 --> 00:13:59.010
New Zealand's capital
city, Wellington, is

00:13:59.010 --> 00:14:00.710
especially at risk.

00:14:00.710 --> 00:14:03.700
It's built on a tectonic
intersection where the

00:14:03.700 --> 00:14:06.480
Australian plate heads
north, and Pacific

00:14:06.480 --> 00:14:08.390
plate drives south.

00:14:08.390 --> 00:14:10.550
Most of the time, the
plates are locked.

00:14:10.550 --> 00:14:13.370
But when the accumulated
stress forces them to

00:14:13.370 --> 00:14:17.410
uncouple, the Australian plate
rides up, triggering an

00:14:17.410 --> 00:14:19.940
earthquake, carrying
the landscape and

00:14:19.940 --> 00:14:21.330
the city with it.

00:14:23.860 --> 00:14:27.830
I reckon this scar must
represent two or three

00:14:27.830 --> 00:14:29.962
movements on the Wellington
fault.

00:14:29.962 --> 00:14:33.860
And we're literally walking
along the fault itself, or the

00:14:33.860 --> 00:14:36.700
eroded scar.

00:14:36.700 --> 00:14:39.270
Well, it looks innocuous enough,
but this really is a

00:14:39.270 --> 00:14:39.880
crime seen.

00:14:39.880 --> 00:14:43.670
This is the site of crustal
collision at work.

00:14:43.670 --> 00:14:47.070
So here we are on the surface,
and what's happening is that

00:14:47.070 --> 00:14:52.220
this side is literally being
ramped up over that side as a

00:14:52.220 --> 00:14:53.470
function of plate collision.

00:15:00.590 --> 00:15:03.170
This is an excellent place
for a lesson in plate

00:15:03.170 --> 00:15:04.390
tectonics, isn't it?

00:15:04.390 --> 00:15:04.870
Oh, it is.

00:15:04.870 --> 00:15:07.750
You can see all the action
you want here.

00:15:07.750 --> 00:15:08.200
Yep.

00:15:08.200 --> 00:15:10.330
You can see the Wellington
fault down here, running

00:15:10.330 --> 00:15:14.267
parallel to the harbor, and it
runs up this gully here, and

00:15:14.267 --> 00:15:17.300
off down in Cooke Strait.

00:15:17.300 --> 00:15:22.890
During the 1855 earthquake, the
plate slipped 15 meters in

00:15:22.890 --> 00:15:27.050
a matter of seconds,
and triggered

00:15:27.050 --> 00:15:28.570
landslides along the shore.

00:15:31.770 --> 00:15:35.360
There was much damage,
but few injuries.

00:15:35.360 --> 00:15:38.820
Since that time, there have
been many reminders of the

00:15:38.820 --> 00:15:40.330
pressure below.

00:15:40.330 --> 00:15:43.740
The most telling was the
earthquake of 1942, which

00:15:43.740 --> 00:15:47.360
demolished nearly every
chimney in the city.

00:15:47.360 --> 00:15:50.300
So this is New Zealand's San
Andreas Fault, isn't it?

00:15:50.300 --> 00:15:51.570
It is.

00:15:51.570 --> 00:15:52.890
It is.

00:15:52.890 --> 00:15:54.280
Exactly, in the sense
that it's running

00:15:54.280 --> 00:15:55.620
through a major city.

00:15:55.620 --> 00:15:58.360
Well, to make matters worse,
this is the capital city.

00:15:58.360 --> 00:16:01.350
So looking into your crystal
ball, when is the next major

00:16:01.350 --> 00:16:02.850
earthquake here?

00:16:02.850 --> 00:16:06.440
I've got an easy answer
for that.

00:16:06.440 --> 00:16:06.850
Let's see.

00:16:06.850 --> 00:16:10.380
There's a 10% chance of
something happening within the

00:16:10.380 --> 00:16:12.800
next 100 years.

00:16:12.800 --> 00:16:14.320
[CYNICAL LAUGHTER]

00:16:14.320 --> 00:16:19.200
That's mumbo jumbo in a sense,
but nevertheless, that's the

00:16:19.200 --> 00:16:22.760
best probability
we can provide.

00:16:22.760 --> 00:16:25.120
And that's the only way we
can really express things

00:16:25.120 --> 00:16:27.830
scientifically with
any certainty.

00:16:27.830 --> 00:16:31.110
Having said that, there could be
a major earthquake tomorrow

00:16:31.110 --> 00:16:32.360
in Wellington.

00:16:36.380 --> 00:16:40.130
But the same destructive process
that Wellingtonians

00:16:40.130 --> 00:16:43.970
fear is also creating
new land.

00:16:43.970 --> 00:16:47.460
Each earthquake pushes rocks
from the ocean bed

00:16:47.460 --> 00:16:49.630
high above sea level.

00:16:49.630 --> 00:16:53.360
The shoreline of North Island is
a unique laboratory for the

00:16:53.360 --> 00:16:57.656
study of how continents grow,
where geologists can see the

00:16:57.656 --> 00:16:59.765
process of accretion at work.

00:17:03.380 --> 00:17:07.240
These rocks, called greywacke,
once lay deep under water.

00:17:19.040 --> 00:17:22.550
Red Rocks is especially
interesting to geologists

00:17:22.550 --> 00:17:25.609
because there's also
a clear chronology.

00:17:25.609 --> 00:17:27.369
It's a geologic time machine.

00:17:33.330 --> 00:17:36.000
So this is a really superb
example is now what were

00:17:36.000 --> 00:17:39.220
formerly deep marine rock
being scraped off the

00:17:39.220 --> 00:17:42.030
descending Pacific plate, and
now exposed above sea level.

00:17:42.030 --> 00:17:46.040
All this material has been
accreted onto the margin.

00:17:46.040 --> 00:17:49.580
Now we're on rocks of Triassic
Age here, Jurassic over there,

00:17:49.580 --> 00:17:53.190
Cretaceous beyond, and so
and so beyond that,

00:17:53.190 --> 00:17:54.440
and it's still happening.

00:18:03.070 --> 00:18:05.710
What've you go?

00:18:05.710 --> 00:18:07.534
Really good greywacke.

00:18:07.534 --> 00:18:08.320
Ah.

00:18:08.320 --> 00:18:09.660
Any fossils.

00:18:09.660 --> 00:18:09.840
No.

00:18:09.840 --> 00:18:12.540
No fossils here, but we have
found fossils in this

00:18:12.540 --> 00:18:13.790
immediate vicinity.

00:18:16.280 --> 00:18:20.650
Greywacke is a young rock, it's
youth symbolizing both a

00:18:20.650 --> 00:18:23.676
country and its recent
oceanic origin.

00:18:23.676 --> 00:18:27.640
A country snatched, as the Maori
legend goes, from the

00:18:27.640 --> 00:18:28.890
depths of the sea.

00:18:32.450 --> 00:18:36.205
Traveling Northwest, Eyles'
journey next takes him to a

00:18:36.205 --> 00:18:42.203
country where the size of
population raises the stakes.

00:18:42.203 --> 00:18:44.720
Japan is one of the
most urbanized

00:18:44.720 --> 00:18:46.080
countries on the planet.

00:18:46.080 --> 00:18:49.690
But despite the stability of its
infrastructure and way of

00:18:49.690 --> 00:18:53.865
life, there is a constant threat
of seismic upheaval.

00:18:53.865 --> 00:18:57.370
It's citizens know that
earthquakes will happen.

00:18:57.370 --> 00:18:59.965
Only the time and place
are unknown.

00:19:04.150 --> 00:19:07.680
People think back to the great
Kanto earthquake that

00:19:07.680 --> 00:19:12.280
decimated Tokyo in 1923,
killing more

00:19:12.280 --> 00:19:14.850
than 142,000 people.

00:19:22.070 --> 00:19:25.570
The event is commemorated every
year on September 1,

00:19:25.570 --> 00:19:29.260
when Japanese emergency services
stage earthquake

00:19:29.260 --> 00:19:30.510
preparedness drills.

00:19:33.710 --> 00:19:38.020
Cities like Fukuroi will, for
a few hours, attempt to

00:19:38.020 --> 00:19:42.120
simulate the chaotic aftermath
of an earthquake, and rehearse

00:19:42.120 --> 00:19:43.370
their reactions.

00:19:46.100 --> 00:19:50.510
Japan sits at the epicenter of
a huge subduction zone, the

00:19:50.510 --> 00:19:53.490
result of a four-plate pileup.

00:19:53.490 --> 00:19:57.730
Offshore, deep in the Japan, or
Nankai Trough, the Pacific

00:19:57.730 --> 00:20:01.430
and Philippine plates are being
pushed under the edge of

00:20:01.430 --> 00:20:03.250
the Eurasian and
North American.

00:20:06.694 --> 00:20:10.650
As So often around the Rim,
there's a deadly rhythm at

00:20:10.650 --> 00:20:14.564
play, as the plates lock,
buckle, and break.

00:20:17.980 --> 00:20:21.790
Fukuroi, in the Shizuoka
region, has the grim

00:20:21.790 --> 00:20:26.860
distinction of being graded
the highest risk.

00:20:26.860 --> 00:20:30.230
Statisticians who have studied
the frequency and location of

00:20:30.230 --> 00:20:34.280
earthquakes in Shizuoka have
determined that Fukuroi's next

00:20:34.280 --> 00:20:35.530
trauma is imminent.

00:20:40.150 --> 00:20:43.640
Nothing can be done to quell the
force that will hit this

00:20:43.640 --> 00:20:47.600
quiet town, but those who live
here know that they can at

00:20:47.600 --> 00:20:52.048
least plan for the event,
however unwelcomed.

00:20:52.048 --> 00:20:59.458
[DISASTER SIRENS SOUND]

00:20:59.458 --> 00:21:05.875
And then, on the stroke of
10:00, the drill begins.

00:21:05.875 --> 00:21:26.760
[SOUNDS OF DISASTER WORKERS]

00:21:26.760 --> 00:21:28.530
Young people take
an active role.

00:21:28.530 --> 00:21:32.650
The experience of earlier
earthquakes suggests they are

00:21:32.650 --> 00:21:34.050
often the quickest to react.

00:21:43.980 --> 00:21:47.920
As the helicopters return, and
the mock wounded are winched

00:21:47.920 --> 00:21:51.790
to safety, the memories of some
track back to earlier

00:21:51.790 --> 00:21:55.567
times, when events such as
this weren't a rehearsal.

00:22:01.670 --> 00:22:06.480
Back in 1944, when the last
earthquake hit Fukuroi, many

00:22:06.480 --> 00:22:08.590
of the victims were children.

00:22:08.590 --> 00:22:12.220
The local school was destroyed,
children buried in

00:22:12.220 --> 00:22:13.780
the debris.

00:22:13.780 --> 00:22:17.350
The new school buildings are
specially braced to reduce the

00:22:17.350 --> 00:22:20.300
risk of collapse.

00:22:20.300 --> 00:22:24.400
Japan was at war at that time,
and many of the local people

00:22:24.400 --> 00:22:27.970
mistakenly thought there
was an air raid.

00:22:27.970 --> 00:22:30.730
You all survived the
terrible earthquake

00:22:30.730 --> 00:22:33.850
of December 7, 1944.

00:22:33.850 --> 00:22:36.470
I wonder, in these tranquil
surroundings, if you could

00:22:36.470 --> 00:22:40.550
just walk us through the
experiences that you had on

00:22:40.550 --> 00:22:42.411
that terrible day.

00:22:42.411 --> 00:22:46.890
[SPEAKING JAPANESE]

00:22:46.890 --> 00:22:52.490
She was in a one-story building,
and she heard people

00:22:52.490 --> 00:22:56.730
on the roof shouting, if you
are there, and if you've

00:22:56.730 --> 00:22:59.160
survived, just sing a song.

00:23:02.130 --> 00:23:04.860
Then they started digging
through the roof where they

00:23:04.860 --> 00:23:06.300
could hear the children
singing.

00:23:10.100 --> 00:23:15.010
She thinks she was one of the
last rescued because where she

00:23:15.010 --> 00:23:18.900
got out of the building, she
saw many bodies and many

00:23:18.900 --> 00:23:21.540
injured children lying
in the school yard.

00:23:27.390 --> 00:23:34.840
It was like when you see houses
collapsing, friends

00:23:34.840 --> 00:23:44.300
dead, parents holding dead
children, neighbors crying,

00:23:44.300 --> 00:23:49.060
looking for missing children,
trying to find them.

00:23:51.870 --> 00:23:55.060
When you have been exposed to
things you don't experience in

00:23:55.060 --> 00:23:59.480
your regular day, how should
I describe it?

00:24:02.350 --> 00:24:03.600
It was a shock.

00:24:11.780 --> 00:24:14.830
There's one thing that
I will never forget.

00:24:14.830 --> 00:24:19.280
The child who is sitting beside
me in class was dead in

00:24:19.280 --> 00:24:21.060
the doorway.

00:24:21.060 --> 00:24:24.550
The memory of that scene
never goes away.

00:24:24.550 --> 00:24:30.760
The neck was caught between two
pillars, and that's the

00:24:30.760 --> 00:24:35.110
thing that hits me especially
hard, because that child had

00:24:35.110 --> 00:24:36.780
been sitting right beside me.

00:24:41.180 --> 00:24:44.520
If I force myself to think,
that's the scene

00:24:44.520 --> 00:24:45.860
that comes to my mind.

00:24:50.440 --> 00:24:54.026
Japan must also faced the
potential threat of volcanoes.

00:24:58.360 --> 00:25:03.850
4,000 meters above sea level,
Mount Fuji is a national icon,

00:25:03.850 --> 00:25:07.050
but it's also a towering menace
to the city that lies

00:25:07.050 --> 00:25:08.380
in its shadow.

00:25:08.380 --> 00:25:13.160
Fujiyoshida is home to nearly
50,000 people, and is part of

00:25:13.160 --> 00:25:16.290
a wider urban area of
3/4 of a million.

00:25:23.965 --> 00:25:28.510
To geologists like Eyles, the
volcano and its setting raise

00:25:28.510 --> 00:25:29.760
many questions.

00:25:35.200 --> 00:25:38.940
The town itself sits on a bed
of lava, the result of the

00:25:38.940 --> 00:25:46.240
eruption of 1707.

00:25:46.240 --> 00:25:50.130
Travelers come from all across
Japan to worship the mountain,

00:25:50.130 --> 00:25:52.440
and also to visit one
of its most famous

00:25:52.440 --> 00:25:54.520
shrines, the Fuji Sengen.

00:25:57.980 --> 00:26:01.780
The shrine is dedicated to the
volcano's goddess, and is the

00:26:01.780 --> 00:26:05.460
setting of the Fuji Festival of
Fire, where, in a two-day

00:26:05.460 --> 00:26:11.470
celebration, giant torches
are lit in her honor.

00:26:11.470 --> 00:26:15.660
Rich in myth and legend, the
volcano's geologic behavior

00:26:15.660 --> 00:26:19.410
was once thought predictable,
but new information suggests

00:26:19.410 --> 00:26:20.800
differently.

00:26:20.800 --> 00:26:24.680
Volcanologist Professor Shigeo
Aramaki is the head of a

00:26:24.680 --> 00:26:28.950
special task force that
was set up in 2002.

00:26:28.950 --> 00:26:31.650
You've been up here
many, many times.

00:26:31.650 --> 00:26:32.140
Right.

00:26:32.140 --> 00:26:34.500
What's special about
this place?

00:26:34.500 --> 00:26:40.080
Well, I have to tell you, we
Japanese volcanologists in the

00:26:40.080 --> 00:26:48.970
past, we reckoned Mount Fuji's
so simple-shaped, and probably

00:26:48.970 --> 00:26:54.110
very simply constructed and
nothing very interesting, as

00:26:54.110 --> 00:26:58.070
compared with other rather
complicated-shaped

00:26:58.070 --> 00:27:00.550
volcanoes in Japan.

00:27:00.550 --> 00:27:05.570
But, well, it was not so.

00:27:05.570 --> 00:27:13.380
We found out Fuji had shown
very interesting, various

00:27:13.380 --> 00:27:19.030
features of volcanic activity,
including pyroclastic flows,

00:27:19.030 --> 00:27:25.170
sector collapse, and sudden
lava flows, and brilliant

00:27:25.170 --> 00:27:28.060
explosions, and whatnot.

00:27:28.060 --> 00:27:34.180
So this is really a showplace
of the volcanic phenomenon.

00:27:34.180 --> 00:27:37.130
[CROWDS YELLING]

00:27:37.130 --> 00:27:41.170
The potential threat is
commemorated every year in an

00:27:41.170 --> 00:27:43.060
elaborate ceremony.

00:27:43.060 --> 00:27:46.550
The goddess of the mountain is
taken from her resting place

00:27:46.550 --> 00:27:49.680
at the shrine, along with a
replica of the volcano.

00:27:55.600 --> 00:27:59.710
The heavy statues, weighing more
than a ton, are carried

00:27:59.710 --> 00:28:02.290
from the temple and paraded
through the streets of

00:28:02.290 --> 00:28:03.540
Fujiyoshida.

00:28:11.670 --> 00:28:15.570
The ceremony dates back many
centuries, reflecting the

00:28:15.570 --> 00:28:18.130
Shinto reverence for
the natural world.

00:28:24.190 --> 00:28:28.080
On her journey, the goddess is
honored and appeased by the

00:28:28.080 --> 00:28:31.670
city and its people.

00:28:31.670 --> 00:28:35.670
And if she remains content,
the city will be spared a

00:28:35.670 --> 00:28:36.920
volcanic eruption.

00:28:45.390 --> 00:28:49.120
When the procession reaches the
center of the city, the

00:28:49.120 --> 00:28:50.490
celebrations begin.

00:28:59.933 --> 00:29:05.700
Most of the Japanese people
never experience in person the

00:29:05.700 --> 00:29:10.200
real eruption, because the
frequency of the eruption is

00:29:10.200 --> 00:29:16.830
so low as compared with other
kinds of natural disasters.

00:29:16.830 --> 00:29:21.500
Even earthquakes, the
medium-sized earthquakes, you

00:29:21.500 --> 00:29:22.750
can experience.

00:29:26.240 --> 00:29:29.320
Well, like the typhoons, the
torrential rainfalls, and

00:29:29.320 --> 00:29:32.080
whatnot, they come every year.

00:29:36.010 --> 00:29:40.532
Meanwhile, in Fujiyoshida,
the festival goes on.

00:29:40.532 --> 00:29:43.880
The giant torches are lifted.

00:29:43.880 --> 00:29:49.090
And all across the city, fires
are lit in honor of the gods,

00:29:49.090 --> 00:29:52.238
and Fujiyoshida becomes
a city of fire.

00:29:52.238 --> 00:29:53.488
[SOUNDS OF PEOPLE WORKING
INDUSTRIOUSLY]

00:30:15.760 --> 00:30:18.640
Despite the apparent risks
of living so close to the

00:30:18.640 --> 00:30:23.500
volcano, many local people
remain unperturbed, preferring

00:30:23.500 --> 00:30:28.130
to see Mount Fuji as
their guardian.

00:30:28.130 --> 00:30:30.970
Yayoi Sato has lived
in Fujiyoshida

00:30:30.970 --> 00:30:33.510
for most of her life.

00:30:33.510 --> 00:30:35.460
So it's a celebration of fire.

00:30:35.460 --> 00:30:38.940
It's a celebration of the
volcano, but the volcano is a

00:30:38.940 --> 00:30:40.050
dangerous thing.

00:30:40.050 --> 00:30:42.210
Are you ever scared about
living on the

00:30:42.210 --> 00:30:44.530
slopes of the volcano?

00:30:44.530 --> 00:30:45.790
[SPEAKING JAPANESE]

00:30:45.790 --> 00:30:46.610
Nothing.

00:30:46.610 --> 00:30:48.410
I'm not scared at all.

00:30:48.410 --> 00:30:49.790
Now what about earthquakes?

00:30:49.790 --> 00:30:52.590
Do you ever experience
earthquakes in Fujiyoshida?

00:31:00.840 --> 00:31:04.340
Yes, I have experienced it,
but it was nothing much.

00:31:04.340 --> 00:31:08.090
You see, I was born in the
1923 during the Kanto

00:31:08.090 --> 00:31:09.340
earthquake.

00:31:11.920 --> 00:31:14.830
My parents put me to sleep on
the second floor of the house.

00:31:14.830 --> 00:31:17.960
They were eating lunch
on the first floor.

00:31:17.960 --> 00:31:21.560
When it started, the ran out
and forgot they had a baby,

00:31:21.560 --> 00:31:22.922
but my father remembered.

00:31:25.770 --> 00:31:29.130
And when he came back to get me,
I was smiling because of

00:31:29.130 --> 00:31:30.380
all the rocking.

00:31:34.190 --> 00:31:40.710
Geologist know that Fuji will
one day erupt again, but on

00:31:40.710 --> 00:31:43.330
festival day in Fujiyoshida,
that seems a

00:31:43.330 --> 00:31:44.759
very distant prospect.

00:32:02.100 --> 00:32:05.160
The more mountainous interior
also bears the

00:32:05.160 --> 00:32:06.590
scars of past events.

00:32:17.090 --> 00:32:21.420
The quiet village of Motosu City
exposes the workings of a

00:32:21.420 --> 00:32:22.670
killer fault.

00:32:25.060 --> 00:32:28.170
This idyllic rural setting is
actually one of the most

00:32:28.170 --> 00:32:32.370
dangerous parts of Japan,
because it lies between two

00:32:32.370 --> 00:32:34.780
large tectonic plates.

00:32:34.780 --> 00:32:39.480
And in 1891, the fault that
runs through this area

00:32:39.480 --> 00:32:42.210
ruptured during a large
earthquake, producing the

00:32:42.210 --> 00:32:44.970
fault scar we can see
just behind me.

00:32:44.970 --> 00:32:48.130
And the block here dropped
suddenly, within a few

00:32:48.130 --> 00:32:50.870
seconds, by six meters.

00:32:50.870 --> 00:32:53.530
And 7,000 people were
killed as a result.

00:33:32.686 --> 00:33:35.260
Faults are pretty common in
the world, but it's really

00:33:35.260 --> 00:33:37.930
unique to get one exposed
like this.

00:33:37.930 --> 00:33:40.140
This is largely because
it's a memorial to

00:33:40.140 --> 00:33:41.870
people that were killed.

00:33:41.870 --> 00:33:44.970
We can see the whole nature
of the offset.

00:33:44.970 --> 00:33:47.505
That surface up there is the
same surface we have down

00:33:47.505 --> 00:33:51.030
there, and there's been about
six meters of vertical

00:33:51.030 --> 00:33:54.030
displacement, and that happened
instantaneously

00:33:54.030 --> 00:33:56.270
during the 1891 earthquake.

00:33:56.270 --> 00:33:59.490
And here we have relatively
young sediments, which are

00:33:59.490 --> 00:34:03.750
juxtaposed against old rock,
and I'm looking right along

00:34:03.750 --> 00:34:07.615
the fault plane along which
that earthquake happened.

00:34:07.615 --> 00:34:11.210
And the boulders have been
turned up along that surface,

00:34:11.210 --> 00:34:14.360
and this whole rock behind me
has been pulverized and

00:34:14.360 --> 00:34:16.539
crushed by that movement.

00:34:34.350 --> 00:34:38.190
Thanks to the development of
plate tectonic theory in the

00:34:38.190 --> 00:34:43.239
1960s, geologists have a clear
understanding of the cause of

00:34:43.239 --> 00:34:46.570
earthquakes, but there are
still many unanswered

00:34:46.570 --> 00:34:51.270
questions surrounding both the
mechanism and their timing.

00:34:51.270 --> 00:34:53.830
Scientists know why earthquakes
happen.

00:34:53.830 --> 00:34:56.274
They are less sure about when.

00:35:04.120 --> 00:35:07.860
Here in the Nankai Trough, one
of the most earthquake-prone

00:35:07.860 --> 00:35:11.340
regions around the Rim,
scientists on board the drill

00:35:11.340 --> 00:35:15.300
ship Tikyu are drilling
kilometers into the ocean bed,

00:35:15.300 --> 00:35:18.830
as they attempt to unravel
the processes at work in

00:35:18.830 --> 00:35:20.330
subduction zones.

00:35:20.330 --> 00:35:24.610
They're hunting for telltale
indicators that precede a

00:35:24.610 --> 00:35:28.160
major quake, and they hope
to find them deep

00:35:28.160 --> 00:35:29.410
under the ocean floor.

00:35:32.950 --> 00:35:37.580
In the on-land geology here in
Japan, we can go back and see

00:35:37.580 --> 00:35:42.870
analogous types of geologic
formations that are 50 million

00:35:42.870 --> 00:35:45.820
years old, 80 million years old,
100 million years old.

00:35:45.820 --> 00:35:48.560
And they're very important in
understanding how the system

00:35:48.560 --> 00:35:51.960
has evolved over long periods
of time, but they don't help

00:35:51.960 --> 00:35:56.390
very much in terms of
understanding the processes

00:35:56.390 --> 00:35:58.450
leading up to the
next earthquake.

00:35:58.450 --> 00:36:01.140
For that, we need to go into
the active fault zones.

00:36:01.140 --> 00:36:05.830
We need to go offshore, where
we can access the fault.

00:36:05.830 --> 00:36:08.940
The Tikyu is one of the world's
most advanced drill

00:36:08.940 --> 00:36:13.690
ships, capable of reaching
depths of 7,000 meters below

00:36:13.690 --> 00:36:16.450
the sea floor.

00:36:16.450 --> 00:36:19.850
The process is highly automated,
and uses gigantic

00:36:19.850 --> 00:36:26.530
robotic arms to maneuver the
heavy piping, and a satellite

00:36:26.530 --> 00:36:29.800
navigation system to help
prevent sudden shifts in

00:36:29.800 --> 00:36:32.755
positioning prompted by
currents or weather.

00:36:35.480 --> 00:36:39.220
This expedition is exploring a
segment of the plate boundary

00:36:39.220 --> 00:36:42.740
that ruptured in an earthquake
in 1943.

00:36:42.740 --> 00:36:46.720
GPS data confirmed that it's
still locked and will, at some

00:36:46.720 --> 00:36:50.280
point, rupture yet again,
threatening the greater Tokyo

00:36:50.280 --> 00:36:55.210
area and the 23 million
people who live there.

00:36:55.210 --> 00:36:58.060
The clues lie in subducting
sediments.

00:36:58.060 --> 00:37:01.810
In the ship's lab, scientists
analyze samples extracted from

00:37:01.810 --> 00:37:05.200
the core so that they can gauge
the effect of pressure

00:37:05.200 --> 00:37:06.240
and temperature.

00:37:06.240 --> 00:37:10.220
By determining the changes in
fluid chemistry leading up to

00:37:10.220 --> 00:37:13.480
a major earthquake, the
scientists hope to capture the

00:37:13.480 --> 00:37:15.335
seismic process in action.

00:37:18.230 --> 00:37:22.460
Phase two of the Tikyu project
is especially ambitious.

00:37:22.460 --> 00:37:26.540
The scientists aim to install a
borehole observation system

00:37:26.540 --> 00:37:30.110
that will link a battery of
sensors embedded in the fault

00:37:30.110 --> 00:37:33.790
line to a shore-based
observatory.

00:37:33.790 --> 00:37:36.870
The sensors will continually
monitor the Earth's crustal

00:37:36.870 --> 00:37:40.900
movement, and provide real-time
data on shifts in

00:37:40.900 --> 00:37:42.270
temperature and pressure.

00:37:47.390 --> 00:37:52.760
The international team hopes to
deploy the system in 2011.

00:37:52.760 --> 00:37:55.440
Should it live up to the
visionary objectives of its

00:37:55.440 --> 00:37:58.510
key scientists, it
could one day

00:37:58.510 --> 00:38:00.690
revolutionize earthquake science.

00:38:06.340 --> 00:38:09.460
Volcanoes have a mystical
allure, impressing with their

00:38:09.460 --> 00:38:11.420
scale and presence.

00:38:11.420 --> 00:38:15.240
Mountain Unzen Volcano, on the
southwest coast of Japan,

00:38:15.240 --> 00:38:17.630
overlooks Shimabara City.

00:38:17.630 --> 00:38:21.390
Like Fujiyoshida, it's a tourist
resort and vacation

00:38:21.390 --> 00:38:23.490
destination.

00:38:23.490 --> 00:38:25.780
It's also a working port.

00:38:30.630 --> 00:38:35.540
Ariake Bay may seem tranquil
today, but it's picturesque,

00:38:35.540 --> 00:38:38.190
scattered islands tell
a different story.

00:38:41.180 --> 00:38:46.600
Unzen is the most infamous
volcano in Japan.

00:38:46.600 --> 00:38:50.060
Its contours tell of its past,
and the early warning

00:38:50.060 --> 00:38:52.970
monitoring system,
it's future.

00:38:52.970 --> 00:38:58.267
Each slope, every outcrop, is a
harbinger of events to come.

00:39:03.630 --> 00:39:09.020
The most deadly was on the night
of May 21, 1792, and it

00:39:09.020 --> 00:39:12.850
was caused not by a volcanic
eruption, but by an

00:39:12.850 --> 00:39:14.100
earthquake.

00:39:17.040 --> 00:39:20.730
Illustrations from the time
depict how the eastern slopes

00:39:20.730 --> 00:39:22.250
of Mount Unzen collapsed.

00:39:25.880 --> 00:39:30.120
Enormous blocks of rock and ash
swept downslope into the

00:39:30.120 --> 00:39:38.580
shallow waters of Ariake Bay,
triggering a tsunami and

00:39:38.580 --> 00:39:42.440
forming the many islands
that dot the bay.

00:39:42.440 --> 00:39:47.460
15,000 people were killed that
day, mostly from the impact of

00:39:47.460 --> 00:39:48.710
the tsunami.

00:39:56.660 --> 00:39:59.950
The scars of seismic activity
are everywhere.

00:39:59.950 --> 00:40:04.785
This gash documents the path of
another pyroclastic flow.

00:40:08.890 --> 00:40:12.990
Even the dome is expanding, as
more lava is pushed out from

00:40:12.990 --> 00:40:14.950
the magma chamber deep inside.

00:40:25.110 --> 00:40:29.470
Bubbling mud and venting steam
are surface clues to the

00:40:29.470 --> 00:40:30.720
pressures below.

00:40:35.805 --> 00:40:40.530
Mount Unzen is still active,
and despite all of the

00:40:40.530 --> 00:40:44.770
sophistication of surveillance
and preparedness drills, is

00:40:44.770 --> 00:40:46.020
unpredictable.

00:40:52.920 --> 00:40:58.820
After almost two centuries of
inactivity, on June 5, 1991,

00:40:58.820 --> 00:41:01.696
Mount Unzen erupted again.

00:41:01.696 --> 00:41:02.946
[DISTANT WARNING SIRENS
SOUNDING]

00:41:12.608 --> 00:41:26.140
[URGENT YELLING]

00:41:26.140 --> 00:41:30.480
43 people were killed, including
three volcanologists

00:41:30.480 --> 00:41:32.175
and an NHK cameraman.

00:41:35.940 --> 00:41:38.990
It's quite humbling sitting
here when you realize the

00:41:38.990 --> 00:41:43.610
power of the 1991 event, when
you see photographs of that

00:41:43.610 --> 00:41:47.183
event and this fiery cloud
sweeping down the valley.

00:41:56.320 --> 00:41:58.500
And these are so dangerous
because they're so

00:41:58.500 --> 00:41:59.405
unpredictable.

00:41:59.405 --> 00:42:02.400
And for weeks prior to that
event, there'd been swarms of

00:42:02.400 --> 00:42:04.840
small earthquakes recording
the ascent of magma in the

00:42:04.840 --> 00:42:08.300
volcano, so is was known that
an eruption was imminent.

00:42:08.300 --> 00:42:12.780
But what caught everybody by
surprise was that upper slope

00:42:12.780 --> 00:42:15.845
of the volcano suddenly,
dramatically collapsed.

00:42:20.531 --> 00:42:25.220
Ash clouds, unimpeded by the lay
of the land, tore straight

00:42:25.220 --> 00:42:26.480
down the side of the mountain.

00:42:35.790 --> 00:42:39.260
Scientists estimate that the
flow was travelling at 100

00:42:39.260 --> 00:42:43.700
kilometers an hour, and that
temperatures reached 450

00:42:43.700 --> 00:42:44.950
degrees Celsius.

00:42:50.590 --> 00:42:54.560
Pyroclastic flows follow the
contours of the land.

00:42:54.560 --> 00:42:59.010
Here at Unzen, the trail of that
flow is clearly marked.

00:42:59.010 --> 00:43:08.640
Giant boulders thrown from the
summit litter the slopes, a

00:43:08.640 --> 00:43:11.455
scale and ferocity difficult
to imagine.

00:43:31.660 --> 00:43:36.250
The trail of destruction was
4 and 1/2 kilometers long.

00:43:36.250 --> 00:43:39.240
It took four years of subsequent
flows and small

00:43:39.240 --> 00:43:43.385
eruptions before the volcano's
force subsided again.

00:43:52.980 --> 00:43:56.840
The damage was compounded
further when the eruption

00:43:56.840 --> 00:44:00.720
triggered a series of mudslides
called lahars that

00:44:00.720 --> 00:44:01.970
buried the town.

00:44:14.960 --> 00:44:17.930
The local school, which was
sited right at the base of the

00:44:17.930 --> 00:44:22.410
volcano and directly in the path
of the pyroclastic flow,

00:44:22.410 --> 00:44:27.140
was particularly badly hit, and
is now a monument to those

00:44:27.140 --> 00:44:28.390
who lost their lives.

00:44:35.920 --> 00:44:39.350
The tectonic forces that are
continually reshaping our

00:44:39.350 --> 00:44:42.585
planet can destroy, but
they also create.

00:44:45.180 --> 00:44:48.300
On the last stop on Nick Eyles
journey around the Western rim

00:44:48.300 --> 00:44:52.850
of the Pacific, he heads back to
New Zealand, but this time

00:44:52.850 --> 00:44:56.620
to the South Island, to explore
this process at work

00:44:56.620 --> 00:44:59.910
on a massive scale.

00:44:59.910 --> 00:45:03.070
As always in geology,
it's the landscape

00:45:03.070 --> 00:45:05.020
that tells the story.

00:45:05.020 --> 00:45:08.460
There were no rivers on this
scale on the North Island, so

00:45:08.460 --> 00:45:10.210
why are they here?

00:45:10.210 --> 00:45:12.030
And what do they bring?

00:45:12.030 --> 00:45:15.850
To find out, Nick meets with
geologist and New Zealand

00:45:15.850 --> 00:45:17.620
prospector John Youngson.

00:45:17.620 --> 00:45:19.890
Very steep.

00:45:19.890 --> 00:45:21.140
Huge bold.

00:45:26.690 --> 00:45:30.310
Further inland, there are
ice-covered mountains,

00:45:30.310 --> 00:45:33.745
sediment-laden rivers,
and deep, cold lakes.

00:45:37.012 --> 00:45:42.230
The Alps are the epicenter of
a titanic battle, where

00:45:42.230 --> 00:45:45.290
glaciers tear down what
tectonics constructs.

00:45:51.480 --> 00:45:53.580
So John, when were
you last here?

00:45:53.580 --> 00:45:54.880
Over 20 years ago.

00:45:54.880 --> 00:45:57.210
Oh, back in the days when I
ran around these mountains

00:45:57.210 --> 00:45:58.570
doing quite a bit of climbing.

00:46:36.735 --> 00:46:38.790
So how do you read that
landscape, in terms of what

00:46:38.790 --> 00:46:40.570
processes are at work?

00:46:40.570 --> 00:46:43.390
Yeah, oh, it's fantastic
here Nick.

00:46:43.390 --> 00:46:47.090
This is plate tectonics
at work.

00:46:47.090 --> 00:46:50.430
We can actually see into the
engine room, if you like, of

00:46:50.430 --> 00:46:53.930
the collision zone between the
Pacific plate here, and just

00:46:53.930 --> 00:46:56.550
over the ridge, over the main
divide, we've got the

00:46:56.550 --> 00:46:59.660
Australian plate.

00:46:59.660 --> 00:47:02.630
And we're in a sea
of greywacke.

00:47:02.630 --> 00:47:05.950
This is the medium that we're
so familiar with in New

00:47:05.950 --> 00:47:08.670
Zealand, and it's literally
being pushed up.

00:47:08.670 --> 00:47:12.370
The maximum rate of uplift is
about 10 millimeters a year.

00:47:12.370 --> 00:47:15.010
Doesn't seem much, but over
millions of years, it amount

00:47:15.010 --> 00:47:16.350
to a huge amount of uplift.

00:47:42.550 --> 00:47:45.135
Now you talk about strong
uplift, what are the processes

00:47:45.135 --> 00:47:48.690
that acting to tear
down the mountain?

00:47:48.690 --> 00:47:51.850
Well, it's mainly this process,
isn't it John?

00:47:51.850 --> 00:47:52.195
Yes.

00:47:52.195 --> 00:47:52.950
The glacier.

00:47:52.950 --> 00:47:56.640
The glacier here is essentially
just a conveyor.

00:47:56.640 --> 00:47:59.930
It is a very efficient
transporter of all this rock

00:47:59.930 --> 00:48:02.320
that is eroded from
the mountains.

00:48:02.320 --> 00:48:05.380
It carries it down the valley as
effectively as a conveyor,

00:48:05.380 --> 00:48:09.000
and then the meltwater from
the ice distributes that

00:48:09.000 --> 00:48:12.380
sediment further downstream,
down the valleys beyond the

00:48:12.380 --> 00:48:13.210
snout of the glacier.

00:48:13.210 --> 00:48:16.180
So gravity's tearing down the
mountains, and the glacier's

00:48:16.180 --> 00:48:18.005
evacuating all the debris.

00:48:18.005 --> 00:48:18.290
Yes.

00:48:18.290 --> 00:48:21.960
It's an ongoing process, a
dynamic equilibrium process,

00:48:21.960 --> 00:48:23.835
where the mountains are being
uplifted, and they're being

00:48:23.835 --> 00:48:25.372
torn down at the same time.

00:48:46.050 --> 00:48:48.710
We're standing right on
a collision zone.

00:48:48.710 --> 00:48:53.000
What happens to rocks that are
being pushed towards us?

00:48:53.000 --> 00:48:53.230
Ah.

00:48:53.230 --> 00:48:55.230
Well, they get metamorphosed.

00:48:55.230 --> 00:48:57.580
So, they're getting squished,
squashed.

00:48:57.580 --> 00:48:59.780
The rocks are literally
re-crystallized and, in the

00:48:59.780 --> 00:49:03.180
process, they re-organize
themselves, and produce lovely

00:49:03.180 --> 00:49:06.930
new flat minerals, and
release fluids.

00:49:06.930 --> 00:49:07.530
So they're cooked?

00:49:07.530 --> 00:49:09.470
They're cooked.

00:49:09.470 --> 00:49:11.800
Those fluids are very important
because, as they

00:49:11.800 --> 00:49:15.760
migrate through the crust, down
beneath the Alps, they

00:49:15.760 --> 00:49:16.660
dissolve metals.

00:49:16.660 --> 00:49:18.560
And they carry those metals
to the surface, and

00:49:18.560 --> 00:49:19.940
among those is gold.

00:49:19.940 --> 00:49:22.150
So there's a lot of gold that
has come out of the Western

00:49:22.150 --> 00:49:25.410
side of the Alps, and a lot of
gold has been mined down on

00:49:25.410 --> 00:49:28.660
the rivers and the planes on
the Western side, on the

00:49:28.660 --> 00:49:29.910
Australian plate.

00:49:49.020 --> 00:49:53.100
The rivers are the final link
on a geologic conveyor that

00:49:53.100 --> 00:49:56.960
transforms and shapes the
South Island landscape.

00:49:56.960 --> 00:50:01.220
The fast-flowing waters act
as a gold machine, sifting

00:50:01.220 --> 00:50:04.100
treasure from chaff.

00:50:04.100 --> 00:50:06.340
The river's very good at sorting
the light minerals

00:50:06.340 --> 00:50:07.970
from the heavy minerals.

00:50:07.970 --> 00:50:09.400
So we just copy the
same processes.

00:50:13.296 --> 00:50:13.783
Ah.

00:50:13.783 --> 00:50:14.270
Ah.

00:50:14.270 --> 00:50:15.190
There we go.

00:50:15.190 --> 00:50:16.442
There's some gold in there.

00:50:16.442 --> 00:50:17.306
There's some gold.

00:50:17.306 --> 00:50:18.735
The machine has worked.

00:50:26.732 --> 00:50:30.960
The journey around the Western
rim of the Pacific is one of

00:50:30.960 --> 00:50:34.300
birth and destruction.

00:50:34.300 --> 00:50:38.570
White Island, a young volcano,
emerges from the sea floor.

00:50:41.220 --> 00:50:45.700
Red Rocks see new land created
by seismic action that

00:50:45.700 --> 00:50:47.457
elevates land from sea.

00:50:50.656 --> 00:50:54.660
High on Mount Cooke lies
rock that originated

00:50:54.660 --> 00:50:58.110
on the ocean floor.

00:50:58.110 --> 00:51:01.320
As the bed of the Pacific
Ocean sinks below the

00:51:01.320 --> 00:51:05.930
advancing continents, its rocks
are melted and recycled.

00:51:05.930 --> 00:51:09.120
The ocean shrinks and
new land is created.

00:51:11.990 --> 00:51:14.940
The birth of a continent
comes at a price.

00:51:23.719 --> 00:51:55.259
[MUSIC PLAYING]