Download Impact on Landscape and Population

National 5 – Natural Hazards Revision Guide
Everything you need to know
Tropical Storms
Tropical storms are found between the Tropic of Cancer in the Northern
hemisphere and the Tropic of Capricorn in the South. They originate over the
eastern side of oceans and move westwards where they cross the land causing
great devastation before dying out. Tropical storms over 74mph are called
hurricanes in the West, cyclones in the East and typhoons in China and Japan.
Causes of Tropical Storms
In order for a tropical storm to form the following conditions need to be met:

Sea temperatures must be over 27°C

Low air pressure

Air spiralling upwards

Large expanse of water

Location between the tropics

Damp, moist air with humidity greater than 60%
Case Study: Hurricane Sandy
Case studies are used to allow for an in depth understanding of a particular
storm and candidate's knowledge should include:

the underlying causes

the impact on the landscape and population

methods of prediction and their effectiveness

role of aid agencies and their effectiveness
Atlantic
Ocean
Hurricane
Sandy
Florida
How did it form?
Hurricane Sandy, a late-season post-tropical cyclone, swept through the
Caribbean and up the East Coast of the United States in late October 2012.
Sandy is only a “Category 1” storm, meaning it is nowhere near as powerful as
its cousin Katrina.
A rare combination of weather fronts has seen the hurricane merge with cold air
from the north, turning it into a “superstorm” with a total diameter of almost
2,000 miles (3,200km), the largest in Atlantic storm history, experts said.
What makes Sandy almost uniquely dangerous, however, is its projected path
which leads from the Atlantic directly into a head-on collision with the coast of
New Jersey. Most tropical storms off the eastern seaboard run directly up the
coast but cold air from the north and from the jet stream to the west are forcing
Sandy towards the shore.
The impact on the landscape and population
Landscape

Trees were knocked over by the strong winds.

Fires from gas explosions destroyed roads and houses.

Flooding of areas in New Jersey and New York including
subway stations.

Power lines were also knocked over leaving millions
without power.
People

149 people were killed – most from drowning or from
fallen trees.

Sandy damaged or destroyed at least 650,000 homes

250,500 insured vehicles.

More than 300,000 business properties were also
affected

Superstorm Sandy caused $65 billion in damage in the
U.S.
Hurricane Sandy: Methods of Prediction
Almost five days prior to landfall, the National Hurricane Center pegged the
prediction for Hurricane Sandy, correctly placing southern New Jersey near the
center of its track forecast. This long lead time was critical for preparation efforts
from the Mid-Atlantic to the Northeast and no doubt saved lives. It gave people
the opportunity to prepare for the hurricane but also emergency services and
government were able to better prepare for the disaster.
Hurricane Sandy: Role of Aid Agencies
A review of federal agency databases and project lists by the News4 I-Team shows less
than $10 billion of the $50 billion in emergency aid has been distributed to local
communities and cities impacted by the storm.
Short Term
American Red Cross
The Red Cross met Sandy’s significant damage with our largest U.S. response in five years.
Our massive emergency relief effort was powered by more than 17,000 trained workers from
all over the country – 90 percent of them volunteers. This response included:

Medical supplies, blankets, food and clothing.
M – Millions
K - Thousands
Long Term
American Red Cross


Money spent to help rebuild housing and communities.
Money donated to help with the physical and mental health services of
people who have suffered from the disaster.
SandyRelief.org

Donations to help people rebuild their homes.
Direct Relief

Grants to help long-term recovery to 28 community service organisations.
Non- profit health centers and clinics, a local fire department and a
community counselling center.
Effectiveness of relief
 The USA is an MEDC and so were able to cope with the aftermath well.
Over the past year, the administration has provided over 230,000 people
and businesses with assistance through its various departments (FEMA,
Small Business Administration (SBA), Department of Labor among
others).
 It highlighted weaknesses in infrastructure which are going to be tackled
to ensure that roads and buildings can cope with a hurricane next time.
Earthquakes
The location of earthquakes
earthquakes
Earthquakes are mainly found along the boundaries of tectonic plates as
shown on the map above. There are bands of earthquakes found all around the
Pacific Ocean e.g. Japan which is known as the Pacific ring of fire. The West
coasts of North and South America are in earthquake zones as is the midAtlantic and the Southern Mediterranean around Turkey and Italy.
Causes of Earthquakes
Earthquakes are caused by the sudden movement of the tectonic plates
which make up the Earth's crust. These plates move in different directions and
can either move towards one another (destructive plate boundary), slide past
one another or move away from one another (constructive plate boundary).
When tectonic plates slide past one another friction builds up and they 'stick'
which leads to a build up of pressure. Eventually the forces become too great
and the crustal rocks snap apart. This sudden movement of the earth is what
we call an earthquake.
Case Study: Indian Ocean Tsunami 2004
A very common case study for earthquakes is the South East Asian Tsunami of
2004. Other case studies include Mexico 1985, San Francisco 1989, Kobe 1995
and Pakistan 2005.
The Underlying Causes
On 26th December 2004 there was a massive and sudden movement of the
Earth's crust under the Indian Ocean. This earthquake was recorded at
magnitude 9 on the Richter Scale and as it happened under the ocean, caused
a devastating sea wave called a Tsunami.
The epicentre of the earthquake occurred 200km west of the island of
Sumatra in the Indian Ocean. The earthquake itself happened due to the
subduction of the Indo-Australian plate under the Eurasian plate. As the
Indian plate (part of the Indo-Australian plate) moved underneath the Burma
plate (part of the Eurasian plate) the crustal rocks stuck as they moved past one
another. At 8am local time, the pressure build up was too great and the
crustal rocks snapped causing an earthquake. When this happened the sea
floor was pushed upwards displacing a huge volume of water and creating
the devastating Tsunami waves.
Impact on Landscape and Population
Landscape

Some smaller islands in the Indian Ocean were completely destroyed

Coastal buildings were completely destroyed making people homeless

Fishing villages were completely destroyed

Lines of communication were cut off including phone and electricity power
lines

Roads and railways were destroyed

Fires broke out due to severed water pipes
People

Approximately 250,000 people are estimated to have been killed including
many tourists on the beaches of Thailand

There was an outbreak of disease such as Cholera due to a lack of fresh
water supplies

There was a lack of food as many fish died and farms were destroyed
Methods of Prediction
Earthquakes are extremely difficult to predict although scientists now know
which areas have a higher risk of earthquakes and can identify frequency
patterns from previous earthquakes. As a result active earthquake zones are
closely monitored for seismic activity including the use of tiltmeters and laser
equipment to measure earth movements and sophisticated sound recording
equipment to monitor earth tremors.
In developed countries such as USA, building earthquake proof buildings,
such as the TransAmerica Pyramid in San Francisco which sways with the
movement of the earth, have helped to reduce the damage caused by
earthquakes. Some countries practice earthquake drills, e.g. Tokyo in Japan,
just as we have fire drills and emergency services are better prepared and
equipped to deal with such a disaster.
Despite all of these measures there were few warnings or successful predictions
of the Indian Ocean Tsunami. Most of the countries affected were developing
countries without the funds for these sophisticated methods of detection.
They also lacked the improved communications which may have allowed
them to evacuate from coastal areas in time. All the warning they received was
the retreat of sea water from beaches before the wave hit.
Role of Aid Agencies
Short Term Aid

Emergency medical aid was provided by The Red Cross

Tents and blankets were provided for the homeless by UNICEF

Temporary shelters were constructed

Bottled water was supplied as there was restricted access to fresh, clean
water

Bulldozers, sniffer dogs and heat seeking equipment were used to detect
people who may have been lost or missing in collapsed buildings

Food supplies given by The UN due to destruction of farmland and
buildings

Clothing supplies would be needed

Air lifting of more serious cases to hospitals in unaffected areas, US
military
Long Term Aid

Roads, electricity supplies and water pipes etc needed to be rebuilt

Houses and other buildings such as schools and hospitals needed
rebuilding

Flood prevention measures such as sea walls to be built
Effectiveness

There was still a huge loss of life

Tourist industry which was a large source of income particularly to
Thailand and Sri Lanka was up and running again after only a few months

Warning through media saved lives in areas such as East Africa

Money was raised initially through TV campaigns but this dried up once
the Tsunami was no longer in the news

Potential corruption and stories of aid not reaching victims of the disaster
Volcanoes
The location of volcanoes
earthquakes
Causes of Volcanoes
Volcanoes are found along constructive and destructive plate boundaries.
When two plates move apart (constructive) the cracks in the crust allow liquid
rock, called magma, to rise from the mantle, through the earth's crust, to the
surface. When this molten rock reaches the surface it is called a volcanic
eruption. Magma at the surface is called lava and it cools and solidifies into solid
rock. This process can repeat itself over many years forming a cone-shaped
mountain or volcano.
Destructive plate boundaries involve two plates moving towards each other, the
heavier plate is forced down below the lighter plate, into the mantle where it
melts. The molten rock rises up to the surface through cracks in the rocks
creating a volcanic eruption. These eruptions are usually very explosive because
they are mixed with gases.
Case Study: Mt. St. Helens 1980
A very common case study for volcanoes is the eruption of Mt St Helens in 1980.
Other case studies include Mt Etna in Sicily and Heimaey in Iceland.
The Underlying Causes
Mt St Helens, Washington began its most recent series of eruptions in 1980
when a massive landslide and powerful explosive eruption created a large crater,
ending 6 years later after more than a dozen extrusions of lava built a dome in
the crater.
The first sign of activity began in the spring of 1980 when a series of small
earthquakes began. After thousands of additional earthquakes and steam
explosions, a cataclysmic eruption occurred on May 18th 1980.
Mt St Helens lies close to a destructive plate boundary where the smaller Juan
de Fuca plate is being forced into the mantle by the larger North American Plate.
Friction and heat cause the plate to melt and as it melts, molten rocks are
formed. The molten rock builds up until it has the chance to reach the surface
through cracks in the earth's crust.
Impact on Landscape and Population
Landscape

The mountain was reduced from a height of 2950m to 2560m as the
eruption created the largest landslide ever recorded.

All plant and animal life living within a 25km radius of the volcano was
killed, including fully grown trees.

Mudflows poured down the valleys killing fish, choking rivers with rock
debris and ripping trees from their roots.
People

61 people died (mudflows, crushed to death and poisonous gases) in
the eruption of Mt St Helens and 198 had to be rescued.

Mudflows destroyed bridges, houses and logging camps.

Ash turned day into night.

The explosion flattened buildings and trees and knocked out power
supplies and telephones.

Ash clouds resulted in airline flights being cancelled.

Ash caused £100 million damage to farm machinery and crops.
Methods of Prediction
Volcanoes are difficult to predict and, although scientists were not able to
give a precise date for the eruption of Mt St Helens, they tried to predict it by
measuring the frequency of earthquakes on the mountain – the greater the
frequency, the nearer the eruption and measuring the size of the volcanic
cone would show the build up of magma in the vent. Scientists can also check
for gas emissions (sulphur dioxide) and increased thermal activity at the
crater. However, even before the eruption, scientists thought that the eruption
of Mt St Helens might still be a few weeks away.
The Authorities were able to evacuate people from the areas surrounding Mt St
Helens after they found out the area affected by the previous eruption and set
up an exclusion zone around the volcano. Emergency services were also on
hand, ready to rescue those people needing help.
Role of Aid Agencies
Short Term Aid

Rescuing stranded people.

Clearing up afterwards - removing the ash from one town took 10 weeks
and cost £1million.

Mobilising people to help clean up, giving employment to 200,000 people
out of work after the eruption.

Over 1 million tonnes of ash were removed from roads, buildings and
airports.

Electricity was restored to the area.
Long Term Aid

Long-term aid was concerned with returning the area to normality, which
took several years.

Millions of trees were replanted.

Compensation was given to farmers.

Channels were dredged to remove logs and levees were built to reduce
future floods.

New tourist facilities were built; 3 million people now visit every year.

A new highway was built.

The federal government gave £700 million to rebuild.

Money was given to redevelop salmon hatcheries.
Effectiveness

The money given by the federal government allowed quick recovery.

Tourism is now more popular than before.

However, environmentally the area has taken longer to recover.

Replanted trees will not be fully grown until 2050 and so the wildlife will
not return to normal levels until then.

Although 61 people lost their lives, this disaster would have been much
worse had it occurred in a developing country where there would be a lack
of money, people, equipment and expertise to carry out the necessary aid
operations.