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