Geography - Hazards

Which hazard is the deadliest?

Earthquakes

State key facts about Mt.Merapi in Indonesia.

• 4th largest population in Indonesia.

• 2.4 million people live within sight of the volcano.

• Most active volcano in Indonesia.

• Soil near the volcano is very fertile.

• Naturally encourage large scale agriculture.

• Part of the ring of fire.

• Densely populated islands.

State key facts about Manizales in Colombia.

• City with 435,000 people.

• On the slopes of Nevado del Ruiz.

• Has a stratovolcano, last majorly erupted in 1984.

• Many people migrated to Manizales in fear of crime and drug cartels.

• But a large percentage of these people live in slums.

• The percieved risk of crime is higher than the percieved risk of volcano erupting.

Define intrusive magma.

Magma that cools, crystallises and solidifies slowly before the surface. Forms coarse-grained igneous rocks like granite.

Define extrusive magma.

Lava that is in contact with the air or sea. It cools, crystalises and solidifies faster than magma underground. Makes rocks like basalt.

Define Sima.

Oceanic crust that is mainly made up of basalt - known as this because they are made of silica and magnesium.

Define Sial.

Continental crust made mainly of granitic rocks - known as this because they are made of silica and aluminium.

Define Asthenosphere.

From the Greek word asthenes meaning weak. Solid layer below the lithosphere. This is where magma is found.

Name the 2 types of crust.

Oceanic and continental.

Describe the oceanic crust.

• It is thinner, younger and more dense.

• Made of broken layers of baslatic rocks known as sima.

• Sima is the lower layer of the Earth’s crust and is found between the oceans.

Describe the continental crust.

• It is thicker, older and less dense.

• Made of mainly granitic rocks known as sial.

• Sial is the upper layer of the Earth’s crust and forms continental masses.

Describe the Mantle.

• Widest section of the Earth - 2900km thick.

• Great heat and pressure within the mantle means the silicate rocks are still in a thick, liquid state and gets denser with depth.

• The rocks in the upper mantle are solid and sit on top of the asthenosphere, a layer of softer, almost plastic like rock.

• The asthenosphere moves really slowly carrying the lithosphere on top of it.

• As you go deeper the density within the mantle increases.

Describe the Core.

• It is the centre and hottest part of the earth. Temperature can reach 5000 degrees Celsius.

• Made mostly of iron and nickel. 4 times more denser than the mantle.

• The outer core is mainly semi liquid and is mainly iron.

• The inner core is solid and made up of an iron-nickel alloy.

• Geologists think that as the earth spins the outer core spins, which creates the Earth’s magnetic field.

• Earth’s greatest heat energy coms from radioactivity.

• The decay of uranium, thorium, potassium and other elements provide a continuous but slowly diminishing heat supply.

Define natural hazards.

They are extreme natural events that can cause loss of life, extreme damage to property and disrupt human activities.

Define human hazards.

A phenomenon or human activity that may cause a loss of life, injury or other health impacts, property damage, social and economic disruption.

What factors determine the impact of the hazard?

General factors like location, population density and income of the country.

What are the 3 main types of hazards?

Geophysical (lithosphere), Atmospheric (atmosphere) and Hydrological (hydrosphere)

Define and give an example of geophysical hazards.

Driven by Earth’s own internal energy sources. For example plate tectonics and volcanoes.

Define and give an example of atmospheric hazards.

Driven by processes at work in the atmosphere. For example tropical storms and droughts.

Define and give an example of hydrological hazards.

Driven by water bodies mainly in oceans. For example floods, storm surges and tsunamis.

What are primary impacts of hazards?

These are impacts that have an immediate effect on the affected area such as destruction of buildings and infrastructure.

What are secondary impacts of hazards?

These are impacts that occur after the disaster as a result of the primary impact sucg as disease, economic recession or contamination of water sources.

Define fatalism.

The belief that all events are predetermined and therefore inevitable.

Define adaptation.

Anticipating the adverse effects of an event and taking appropriate action to prevent or minimise the damage or taking advantage of opportunities that may arise.

Define the Park Model.

Plots the quality of life after a disaster has occurred agianst the time after the disaster has occurred.

Define mitigation.

Actions taken to minimise or eliminate long-term risks caused by hazards or disasters.

State how perceptions of hazards are formed.

• How we perceive a hazard is based on how it may affect our lives.

• It is the presence of people that makes a natural event a hazard.

• The pressure of increasing population and the subsequent demand for land has resulted in building in areas with increased risk.

• Hazard perception is influenced by socio-economic status, education, religion and culture, past experiences, values, personality and expectations.

How has the economic damage from natural disasters changed from 1900 to 2019?

It has increased by £300 billion.

What are some human responses to hazards?

• The main response is to reduce risk to life and equity.

• ADAM (Automatic Disaster Analysis and Mapping) has been developed to reduce disaster response times.

• The database pools information from the US Geological Society, World Bank and World Food Programme.

• This allows immediate access to information such as the scale of the disaster, what supplies are available locally and local infrastructure.

What is risk sharing?

Insurance to ensure that the cost of a hazard is spread between several parties.

What are the 4 parts of the hazard management cycle?

1. Preparedness

2. Response

3. Recovery

4. Mitigation

What happens during the first stage (preparedness) of the Hazard management cycle?

• It includes raising public awareness which can reduce the impact of the hazard.

• Knowing what to do just after the hazard has occurred can speed up the recovery process.

• Different areas will have different levels of preparedness.

What happens during the second stage (response) of the Hazard management cycle?

• Speed of the response depends on the effectiveness of the plan that has been put in place.

• Immediate response focuses on saving lives and coordinating medical assistance.

• Damage assessment helps plan for recovery.

What happens during the third stage (recovery) of the Hazard management cycle?

• Restoring the area that has been affected to normality.

• Short term = restoration of services.

• Long term = planning and reconstruction to pre-event levels.

What happens during the fourth stage (mitigation) of the Hazard management cycle?

• Actions aimed at reducing the severity of an event and lessening it’s impacts.

• Some examples are altering building designs to withstand earthquakes and hurricanes.

• It could be natural barriers like coral reefs.

What are the 3 R’s in the Park Model?

1. Relief

2. Rehabilitation

3. Reconstruction

What happens during relief?

The immediate local and possibly global response in the form of aid, expertise, and search and rescue.