topic 1- tectonic hazards

Natural hazard

An extreme event that causes loss of life, severe damage to property or severe disruption to human activities

Social

To do with people

How many plates is the earths crust divided into?

7 large ones and 12 smaller ones

Environmental

To do with the relationship between humans and the natural world

Economic

How well a country is doing in making goods and money

Give three reasons why a natural hazard would have the most impact on an LIC

• more poor quality housing and healthcare

• Poor infrastructure means its harder to reach affected people

• Less money to protect people (eg earthquake proof buildings) and less money for responses (e.g. providing food)

What do convection currents do?

Cause plates on the mantle of the earth to move

Convection currents explained

1. Magma below the surface is heated by the core and rides to the crust where it cools and sinks to be reheated again

2. Friction caused by the rising currents means that the plates are pulled forward or dragged back (plate tectonics)

The two types of crustal plates

Oceanic & continental

Oceanic plates

Denser & thinner

Continental

Less dense and thicker

The three plate boundaries

Constructive, conservative and destructive

Destructive margins

An oceanic plate and continental plate move towards eachother and collide the denser oceanic plate is subducted beneath the continental plate

What causes volcanic activity and earthquakes at destructive plate boundaries?

The melting plate causes volcanic activity and the stress causes earthquakes

Collision zones

When continental plates of the same density collide, they buckle up, creating fold mountains- earthquakes occur here but no volcanic activity

Example of a collision zone

2015 Nepal earthquake

Constructive plate boundary

Where plates pull apart, allowing magma to reach the surface and erupt through fissures and faults, creating volcanoes or earthquakes

Conservative plate boundary

When plates move in the same or opposite direction against eachother- ash they move their edges stick together and cause stress to build up until one plate jolts forward, no volcanoes are formed here but earthquakes and rift valleys are formed

How thick is the crust of the earth?

30-65km thick

How thick is the mantle of the earth?

2800km

How thick is the outer core of the earth?

2700km

How thick is the inner core of the earth?

1600km

The order of the layers of the earth from outside to inside:

Crust, mantle, outer core, inner core

Give one social factor as to why people still live in areas at risk of tectonic hazards

• they live near friends and family and have a job there

Give an environmental factor as to why people live in areas at risk from tectonic hazards

Volcanic areas have fertile soils, valuable minerals, geothermal energy, and tourism opportunities

Give an economic factor as to why people live in areas at risk from tectonic hazards

• they have confidence that their government has the ability to ‘fix’ things