00.00 Japanese
landslide Video
Exts
Durham University Earth Sciences dept
Researcher
at computer with Japan landslide images
Guide Voice: In August 2004, the precise moment
when a landslide reached catastrophic failure was caught on camera
by a team from the Japanese ministry of Land, Infrastructure &
Transport. In this instance there was sufficient warning, and
nobody was injured, but on average landslides kill over 8,000
people every year, mostly in the developing world.
Researchers from Durham University's International Landslide
Centre visited the Japanese landslide site in order to map and
measure its movement and analyse soil samples in the laboratory. At
a time when we seem increasingly powerless before the ravages of
nature, The International Landslide Centre has made great strides
in understanding and predicting landslides.
00:44 SOT: David Petley, Reader, Dept
of Geography, Durham University - "The primary
aim of the Landside centre is to help developing countries in
particular to deal with landslide problems that they face, and
there are three main activities that we undertake. First and
perhaps most important is we undertake fundamental research into
landslide problems in those countries. So we go out and we measure
landslides, we use lab techniques to investigate them, we try to
develop schemes for assessing where landslides might happen in the
future. The second activity that we do is a disaster response, so
we have a team on 24 hour standby to fly out to developing
countries to help them to deal with landslide problems that have
occurred at very short notice. And the third activity that we
undertake is to try to build up capability within developing
countries to deal with landslide problems."
01.25 Laboratory
shots
Soil
samples
Soil
sample into Back pressured shear box
Results
on screen two shot researchers
Guide Voice: In order to understand the nature
of landslides they have developed a number of research techniques
of their own. The analysis of soil samples taken from within
landslides has taught them a great deal about how a landslide is
set off. They designed and built their own "Back pressured
shear box" to simulate conditions within a landslide. Rainfall
is the major factor in the majority of landslides that are not
caused by earthquakes. So inside this device the water pressure is
gradually increased within the soil sample, and its behaviour is
then monitored on a computer.
001.57 SOT David Petley (over cu graph
on screen pointed out) - "So this is the water
pressure increasing simulating the rainfall and as the rain falls
onto the soil and sinks through the water pressure goes up. This is
the movement of the landslide initially there's no movement and
round about here we start to get a little bit of movement, the
landslide starting to slide starts to accelerate and then suddenly
around about this point it suddenly fails and the landslide
accelerates down the slope to a catastrophic
failure."
02.22 Group
Laser scanning in field
CU
scanner operated
Scanner
turning
3D
models on computer
Guide Voice: Another technique they have
developed is to use lasers to scan a suspected landslide site. The
laser tracks back and forth across a slope to build up an exact
image. This can then be mapped into a detailed 3D model. Any
subsequent movement is then detected by comparing a new scan to the
original model. By interpreting the pattern of movement in a slope
at an early stage, they can then extrapolate its likely behaviour
in the future:
02.49 SOT: David Petley -
"It's quite exciting because we are now in a position to
predict pretty much exactly when a landslide might happen and how
fast it might be when it does occur. This is done really in a very
simple way, we measure the movement of the landslide, perhaps just
by putting pegs into the slope and measuring the movement of the
pegs and we can interpret the movement pattern to tell us what the
landslide might do in the future and under certain conditions we
can actually predict exactly when the slope might move and whether
it will be a very catastrophic or a very rapid failure or a slow
movement."
03.21 Landslide
photos on computer screen
Researcher
in vision
CU
photos buried roads and lorry stuck
Guide Voice: In the case of small scale
landslides a few hours warning could save lives, and the Landslide
Centre believe that in the case of large scale slides they could
predict them days or even weeks ahead. This life saving expertise
is currently being deployed in a number of countries in the
developing world,and is also being used to mitigate the impact of
landslides by advising on the construction and sighting of roads in
areas like Nepal, where 70% of roads are destroyed within 3
years.
ends (Dur: 3 mins.46
secs.)
