Transcript Managing Hazards

Managing Hazards
Revision notes
What is a Natural Hazard?
A Natural Hazard is any natural event that has the potential
to endanger human life, the economy and property.
This unit is all about the management of hazards. You
have studied tropical storms (hurricanes), earthquakes
and volcanoes.
For each hazard you will look at it’s causes, the effects it
has (on people, the environment and the economy) and
how the hazard is managed (in terms of prediction,
prevention of damage, preparation of communities)
You will be expected to do this for both MEDCs and LEDCs
TROPICAL STORMS
Tropical Storms
occur between the two
tropics- Cancer and
Capricorn. It is in this area
where the temperature of
the sea occurs at over
27˚C; which is the
essential factor needed to
kick-start a tropical storm.
The highest number
of storms exist in the North
Pacific Ocean. The most
affected area being South
East Asia receives an
average of 26 storms per
year. The least affected
area is India where there
is an average of 2 tropical
storms per year.
Tropical storms become hurricanes when
their wind speed is over 74miles per hour (a
category 1 storm). Our 2 cases studies were
the worst category of hurricane, category 5,
with wind speeds over 149miles per hour.
Location
*Hurricane Floyd struck on the 16th September 1999 and followed the eastern coast of America all of the way from Florida
to Maine until it eventually died out.
*It formed in the gulf of Mexico out at sea before hitting the Caribbean islands and mainland America.
•The width of the hurricane was estimated to reach around 500km and it was classified as a category 5 hurricane
•Prevention, preparation and prediction measures limited human losses
Effects
*Hurricane Floyd claimed the lives of 79 people.
Solutions and Management
*42 973 homes sustained some degree of damage
*14 states from Florida to Maine were effected
*Agricultural costs were estimated at $1 billion
*47 people died in North Carolina after 500mm of rain flooded 30
000sq km
Costs of rebuilding £4 Billion
*The path of Hurricane Floyd
Prediction - The National Hurricane Centre tracked the
storm using its satellites, this allowed 4 million people to be
evacuated.
Preparation - The evacuation was well planned, supported
by the army and hundreds of hurricane shelters.
Prevention - People in the USA are educated on how to
survive a hurricane by the government, tips given include
turning off gas, removing loose objects from outside and
stocking up on medical supplies, a radio, food and water.
Buildings are well constructed to withstand high winds,
floods and storm surges.
Aid – The USA relies on internal aid for it’s own government,
the US government gave £1.5 billion and whilst FEMA
(federal Emergency Management Agency) gave £0.8Billion
Orissa Cyclone – LEDC (Hurricane)
Location
On 29th of October 1999, a cyclone (hurricane) emerged from
the Bay of Bengal. With winds up to 300 km/h and 30 feet tidal
waves, it affected the state of Orissa for more than 36 hours.
The impacts on people and the environment were massive
because of poor preparation.
• Effects
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20,000 people and 700,000 cattle died.
90 million trees have been uprooted or damaged.
20 million people were made homeless
5 million farmers are out of work
1.2 million hectares of standing cropland were destroyed.
£1.5Billion damage
Solutions
•Preparation and Prediction – The Indian government saw the development of the cyclone on it’s satellites but couldn’t warn people
because of low literacy rates (49%), poor access to radios and the isolated nature of many villages.
•Prevention - There are only 27 cyclone shelters in this region for over 20 million people who live in the state. Building codes do not
protect buildings against the forces of cyclones.
•Response - It took three days for relief efforts to begin. Five days after the storm, the co-ordination centre consisted of six
workers, two telephones and a fax machine. Fishermen have now been issued with radios following the storm so that they can warn
each other and people on land if there are future cyclones.
•Aid - India turned down a United Nations offer for an international fund-raiser, but countries including the US, Britain, Canada and
Germany sent donations. About $20.8m had been pledged by March. The Indian government tried to deal with the disaster on
it’s own initially.
The Structure Of The Earth
Tectonics is the study of the Earth’s internal structure and the
movement of tectonic plates that make up the Earth’s crust.
Convection
currents move
the plates above
CrustHard surface
made of two
different types
of layers:
ContinentalThicker, older less
dense
Oceanic- Thinner,
younger, dense
(heavier)
MantleMolten rock,
mainly silicates.
CoreIron and nickel,
temperatures
reach 3700
degrees C and
the pressure are
very high.
Outer CoreLess pressure,
made from Iron
and Nickel; its
molten!
Location of Volcanoes and earthquakes.
Volcanoes and earthquakes mainly occur along
plate boundaries where magma can escape
from the earth’s mantle or where stresses
build up between 2 plates rubbing together.
An exception to this includes Hawaii, which
is found in the middle of the Pacific plate
over a hot spot. Examples of plate margin
types are linked to the map.
Earthquake
location
Constructive margin
Destructive margin
Collision margin
Conservative margin
Types of plate margin
Type of
Plate Margin
Diagram (add Labels)
What happens
Effects.
World example.
Constructive
Convection currents in the mantle move two plates
apart.
The gap in between is filled by magma.
This erupts onto the surface and cools as new
land.
Earthquakes
and
Volcanoes
The mid Atlantic Ridge,
where the Eurasian plate
moves away from the
North American plate.
Destructive
An oceanic plate (dense) is pushed towards a
continental plate (less dense) by convection
currents.
The oceanic plate is subducted (pushed under) the
continental plate.
As it descends friction and heat from the mantle
melt the plate. Some distance from the margin
magma re-emerges at the surfaced to create a
range of mountains.
Where the 2 plates slide past each other friction
builds and is released as earthquake energy.
Earthquakes
and
Volcanoes
Japan, where the
Philippines sea plate is
pushed under the
Eurasian plate
Collision
2 plates of similar density are forced toward each
other. Neither plate descends into the mantle.
The 2 plates crumple and fold into mountains.
Fold
mountains
and some
earthquakes
The Himalaya, where the
Indo Australian plate is
colliding with the Eurasian
plate
Conservative
2 plates slide past each other at different speeds.
As they move past each other friction builds.
When this friction is eventually released it sends
shock waves through the earth’s crust.
Earthquakes
only
San Andreas fault in
California, where
Location
KOBE, JAPAN – An earthquake in an MEDC
Kobe is located in the south east of Japan, near
a destructive plate margin. Although further
from the plate margin than most of the cities in
Japan Kobe is found on a fault line. The quake
measured 6.9 on the Richter scale. The Pacific
plate is being pushed under the Eurasian plate,
stresses build up and when they are released the
Earth shakes. The focus was only 16km below
the crust. It happened on the 17th Jan 1995 at
5.46am.
Effects
•More than 5000 died in the quake
•300,000 were made home less
•More than 102,000 buildings were destroyed in Kobe,
especially the older wooden buildings.
•Estimated cost to rebuild the basics = £100 billion.
•The worst affected area was the centre. This was
because it was built on easily moving ground which
LIQUIFIED, allowing building to collapse and sink.
Solutions
Preparation – A lot of the buildings in Kobe and Japan made after the 1960s are earthquake proof (necessary by law) with counterweights on the
roofs and cross steel frames. Many of the damaged buildings in Kobe were built before this period and were made of wood, which caught fire.
People are educated on earthquake preparation in Japan.
Prediction – Japan has the world’s most comprehensive prediction programme with thousands of seismometers and monitoring stations in Japan
designed to give warning. Kobe hadn’t had an earthquake in 400years and had less prediction equipment than other areas of Japan.
Responses – Fires broke out and emergency services struggled to put them out because of the scale of the damage, blocked roads and broken
water pipes. Aid did not reach Kobe from other parts of Japan because of damaged roads and rail links. Water, electricity, gas, telephone services
were fully working by July 1995. The railways were back in service by August 1995. A year after the earthquake, 80% of the port was working but
the Hanshin Expressway was still closed.
Aid – The Japanese rejected international offers of aid and dealt with the earthquake itself. All of the homeless people were dealt with reasonably
quickly and the city recovered thanks to government money.
Location and background.
The epicenter at Izmit in Turkey's
heavily populated northwest - struck
at 0302 hours local time on 17
August. The geographical fault
involved was the North Anatolian
Fault.
The Izmit quake - August 1999
Effects
Social
More than 20,000 died
The earthquake left some 17,000 people dead and
200 000 homeless. Tens of thousands spent 2 years
after the quake living in tents
Economic
Many shopkeepers unable to re-open businesses
after thousands migrated after the quake
Many roads needed fixing as well as rail and
telecommunications
Environmental
700,000 tonnes of oil was set ablaze
65,000 buildings were destroyed because of poor
construction
The Turkish landmass is a small tectonic plate which
is being squeezed like a pip between the two bigger
plates, the Eurasian and Arabian. It is therefore
moving west, so it is a conservative
plate
boundary.
Solutions/Responses
Responses - The response was very slow after the quake. Lives were lost due to inefficiency.
Foreign aid was and resources (food, tents) were given by the Red Cross.
After the quake 5000 people were trained in earthquake rescue, but people lived in tents for over
two years after the quake which shows a lack of efficiency. However building codes have not
improved in Izmit.
Effects
Location
•847 People Killed - 300 from collapsing roofs
100 from the mud flow, the rest from disease in the
evacuation centres including measles.
•On the Island of Luzon in the
Philippines in South East Asia.
Next to the Eurasian and
Philippine Plate.
•650,000 workers lost jobs
•$700 Million Damages
•It exploded in 1991
•1.2million people lost homes
•It is one of a chain of
volcano's known as the Luzon
volcanic arc, which is the
result of the Oceanic Philippine
plate being subducted under
the lighter Continental
Eurasian plate.
•The Volcano is slightly offset
from the plate boundary as,
when the Oceanic plate is
subducted it is melted and
forced away as molten magma
by the high pressures exerted
on it. It then resurfaces as
the density of the molten
magma becomes lower than
that of the rock, and so it
pushes it up through the small
cracks and explodes out
through a volcano.
Electricity went off, water was contaminated, road
links were destroyed, and telephone links were cut
Prediction
Prevention
Preparation
What they actually did
Evacuation people if an
eruption is predicted
from gases released.
There was no
monitoring until the 3rd
of April but
seismometers were put
into place.
58,000 people
evacuated up to a
radius of 30km.
Alert systems put into
place to warn of
eruption.
Government Shelters.
Evacuation camps built
for refugees.
Warning sign like gas
and steam looked for.
Long and short term aid
organized.
What they could have
done
Set up permanent
monitoring points,
divert lava flows with
use of dynamite, or use
satellite images to look
upon volcano site for
changes in land
surface.
Placed strategies for
long term aid and
disease control in
evacuations
prepared for.
Storage of medical
supplies food ect. and
water in preparation for
disaster.