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What boundary?
A
destructive
plate
boundary
A
constructive
plate
boundary
A
conservative
plate
boundary
A linear feature
between 5 tectonic
plates that move away
from each other
A Plate boundary
where the plates
move alongside each
other causing
earthquakes
A plate boundary where
the plates move towards
each other causing
earthquakes and/or
volcanoes
EARTHQUAKES
What is an Earthquake?
• An earthquake is the result of a sudden
release of energy in the Earths crust
that creates seismic waves.
Epicentre – The location
on the surface directly
above the focus of an
earthquake
Focus – the location
within the earth
where underground
rocks move and
sends out
earthquake waves
Seismic Waves – shock
waves created at the focus
and sent out in all directions
through the earth
Fault
a crack in the
earth where movement
occurs
EPICENTRE
SEISMIC WAVES
FOCUS
FAULT
How do we measure Earthquakes?
The Richter Scale
measures the energy
released by an
earthquake at its focus.
The energy is measured
using a Seismograph
Earthquakes are measured using machines called
Seismometers.
The depth of the wave is its amplitude.
The more the ground shakes, the greater the
amplitude of the wave. So the bigger the vibration,
the longer the spike on the graph, and the more
damage it will cause.
The amount of energy released in an earthquake is
called its magnitude
This is measured on the Richter Scale
An increase of 1 on this scale means a 30 fold
increase in their energy
The Mercalli Scale
• The Mercalli Scale describes the damage caused by the
earthquake
• I Barely felt
• II Felt by a few sensitive people, some suspended objects may
swing
• III Slightly felt indoors as though a large truck were passing
• IV Felt indoors by many people, most suspended objects swing,
windows and dishes rattle, standing cars rock
• V Felt by almost everyone, sleeping people are awakened, dishes
and windows break
• VI Felt by everyone, some are frightened and run outside, some
chimneys break, some furniture moves, objects fall from
shelves, slight damage, plaster on walls might crack
• II Considerable damage in poorly built structures, felt by
people driving, most are frightened and run outside, loose
bricks fall from buildings
• VIII Slight damage to well built structures, poorly built
structures are heavily damaged, walls, chimneys, monuments
fall
• IX Underground pipes break, foundations of buildings are
damaged and building shift off foundations, considerable
damage to well built structures
• X Few structures survive, most foundations destroyed, water
moved out of banks of rivers and lakes, avalanches and
rockslides, railroads are bent
• XI Few structures remain standing, total panic, large cracks in
the ground
• XII Total destruction, objects thrown into the air, the land
appears to be liquid and is visibly rolling like waves
The Haiti Earthquake
On 12 January 2010, a magnitude 7 earthquake hit Haiti at 16:53
local time. The earthquake’s epicentre was 25 km west of Port-auPrince, the capital. Most people, businesses and services were
located in the capital.
Haiti lies right on the boundary of the
Caribbean and North American plates.
There was slippage along a conservative
plate boundary that runs through Haiti.
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Social impacts of the earthquake (effects on people)
3 million people affected.
Over 220,000 deaths.
300,000 injured.
1.3 million made homeless.
Several hospitals collapsed.
http://www.youtube.com/watch?v=CtBXTvtFaCU
http://youtu.be/OTa65aIifto
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Economic impacts of the earthquake (effects on money and jobs)
30,000 commercial buildings collapsed.
Businesses destroyed.
Damage to the main clothing industry.
Airport and port damaged.
• Many of the effects were immediate or primary, eg injuries
from falling buildings. Some secondary effects didn’t happen
until many months later, eg cholera outbreaks. The effects of
this earthquake were particularly bad because of the following
reasons:
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There were very few earthquake-resistant buildings.
Buildings and other structures were poorly built.
The epicentre was near to the capital.
There were few resources to rescue or treat injured people.