Natural Hazards
Conservative plate margin
Constructive plate margin
Destructive plate margin
involves an oceanic plate and a continental plate. The plates move towards one another
As the plates collide, the oceanic plate is forced beneath the continental plate. This is known as subduction. This happens because the oceanic plate is denser (heavier) than the continental plate.
When the plate sinks into the mantle it melts to form magma. The pressure of the magma builds up beneath the Earth's surface
The magma escapes through weaknesses in the rock and rises up through a composite volcano. The volcanic eruptions are often violent, with lots of steam, gas and ash.
the plates move apart from one another.
When this happens the magma from the mantle rises up to make (or construct) new land in the form of a shield volcano. The movement of the plates over the mantle can cause earthquakes.
the plates move past each other or are side by side moving at different speeds.
As the plates move, friction occurs and plates become stuck.
Pressure builds up because the plates are still trying to move.
When the pressure is released, it sends out huge amounts of energy, causing an earthquake
The earthquakes at a conservative plate boundary can be very destructive as they occur close to the Earth's surface. There are no volcanoes at a conservative plate margin.
Haiti Eathquake
location
located in the Caribbean. it occupies the western part of the island Hispaniola.
The earthquakes epicentre was near the town of Leogane, which is approximately 15km west of Haiti's capital. This was a very shallow earthquake as the focus was only 8km
when
12th January 2010
time
16:53 local time
magnitude
7.0 on the richter scale
Plate boundary
Haiti is situated to the north of the Caribbean Plate on a conservative) plate boundary with the North American Plate
The North American plate is moving west. This movement is not smooth and there is friction between the North American Plate and the Caribbean Plate. Pressure builds between the two plates until it is released as an earthquake
Effects
By January 24th a total of 52 aftershocks measuring 4.5 or greater had been recorded.
Created a very small, localised tsunami, which swept 3 people, boats and debris into the ocean.
An estimated 316,000 people died, and a further 300,000 had been injured
30,000 commercial buildings had collapsed or were severely damaged
Thousands of bodies left to decompose on the streets and pavements
New Zealand Earthquake
when
22nd February 2011
time
12:51pm
effects
181 people were killed
Over 50 per cent of the city's buildings were damaged
Water and sewage pipes were damaged
Businesses were closed for a long time
responses
International aid was provided (around $6-7 million)
Aid workers from charities such as the Red Cross came to help
Areas were zoned to assess damage
300 Australian police officers were flown in
$898 million in building insurance claims
Water and sewerage were restored to the city by August 2011