1. Tectonic Hazard Human Impacts

2. What is a tectonically active area?
A tectonically active area is one that experiences events and hazards such as volcanoes and earthquakes.
Normally, tectonically active areas lie on plate boundaries.
The type of tectonic event depends on the plate boundary.
The most famous tectonically active place is the ‘Pacific Ring of Fire’

3. Why do people live in Tectonically Active Areas?
Population Growth: Urbanisation and economic development are forcing more people to live near tectonically active areas. 20% of the worlds population now live within volcanic zones. (A2 Geography by Edexcel).
Poverty: In many countries people are simply to poor, not to live in hazardous areas. They cannot afford to move or change location. (
Inertia: There may be traditional, historical or cultural reasons for living close to volcanoes and this may prevent people from moving away.

4. Why do people live in Tectonically Active Areas?
Fertile Soils: The minerals released during volcanic eruptions make the soil extremely fertile and ideal for agriculture. In countries like Indonesia, Philippines and El Salvador you will find people farming up very steep volcanic slopes, often building terraces to make farming easier. (
Ignorance: Some people are simply unaware that they are living in a tectonically active area.
Geothermal Energy: Where there is volcanic activity, it is usually possible to source the geothermal energy. For example, Iceland uses Geothermal energy.

5. Range of impacts in contrasting locations
In developed countries, major tectonic events cause higher economic costs due to the large investment in infrastructure whereas a hazard of the same scale in less developing countries would cause more deaths.
Lower developed countries. Without natural buffers the impact of the hazard are greater.
C.Dunn et al Phillip Alan Edexcel A2 Geography (2009)

6. Economic costs Direct costs e.g. immediate repair of buildings
Indirect costs e.g. loss of earnings due to a disruption to working and tourism. E.g. loss of trade (Fukushima tsunami)
Economic cost is generated by two types. Direct costs= from earthquakes demolishing buildings.

7. Human costs
90% of all deaths due to natural disasters occur in the less developed world.
Lower capacity to reduce impacts and recover from destruction. (P.Byrne et al Edexcel A2 Geography (2009)).
Primary Casualties: Killed directly from the hazard e.g. lack of warning systems.
Secondary casualties: Survive initial hazard but affected by lack of resources and medical care.
Tertiary Casualties: People who suffer from pre-existing medical conditions that are worsened by hazard.
The severity of the impacts depends upon human impacts not just physical impacts for example population density.
C.Dunn et al Phillip Alan Edexcel A2 Geography (2009)

8. 2010 Haiti Earthquake
Haiti is the poorest country in the western hemisphere so the earthquake of 7 mms (CBS News) had major impacts.
(2:34-4:23)
mms= moment magnitude scale

9. The range of hazards associated with different types of tectonic activity
Earthquakes are a tectonic hazard but can be associated with these hazards as well:
Ground displacement- can cause impacts on structures but can also lead to secondary hazards like fires
Landslides- the movement of earth down a slope, this can lead to destruction of structures.
Liquefaction- buildings can sink into the ground as water rises with the vibration of the ground.
Tsunamis - caused by earthquake tremors under water, this can lead to flooding causing water damage to property at least Asian tsunami, caused by an 9.0 magnitude earthquake
C.Dunn et al Philip Allan edexcel a2 geography 2009

10. ASSOCIATED HAZARDS CONTINUED
Volcanoes are a tectonic hazard and are associated with these other hazards. Lava flows- the flow of liquid rock down a volcano's slops and can travel from a human walking pace to around 100 km h-1 Explosive blasts- outbursts of rock and lava propelled by gases Ash flows- are dense masses of gas that flow down the sides of volcanoes Ash falls- clouds of ash are throw into the atmosphere and cared by the wind – 2010 Icelandic eruption-Eyjafjallajoekull Mudflows- occur on volcanoes with large deposits of ice and snow forms a muddy liquid the consistency of cement. Glacial outburst- masses of water or ice released from a glacier by the heat of a volcano Poisonous gases- are released from volcanoes before during and after the eruption- these are sulphur dioxide and trioxide
C.Dunn et al Philip Allan edexcel a2 geography 2009

11. Trends in frequency and impact over time.
“Tectonic event: A physical occurrence
resulting from the movement or
deformation of the Earths crust”
Dun Et Al (2009)
The cause of tectonic
events were first
theorised by Wegener

12. Trends in frequency and impact over time.
The first and most obvious trend that occurs in relation to frequency of tectonic activity is magnitude and occurrence. Generally large tectonic activity only occurs rarely and small tectonic activity occurs frequently. However when large a large magnitude event occurs it is usually Devastating.

13. Trends in frequency and impact over time.
Inevitably as the global population rises more people are going to be affected by disasters. There will be more people at the event when it occurs to be affected. People will be more likely to live in a worse location (near a plate boundary), as space becomes harder to find.
Hazard x Vulnerability
Risk=
Capacity to cope

14. Trends in frequency and impact over time.
Since the 1500’s fatalities had been increasing due to tectonic activity, however after 1955 the overall trend in deaths had began to decrease due to the increase in planned reactions and preparation for tectonic activity.

15. Trends in frequency and impact over time.
Overall the amount of tectonic activity
being recorded over time has increased,
this is due to the increased amount of
seismograph stations around the world.
Dun Et Al (2009)