Edexcel Geography A-level Tectonic Processes and Hazards Flashcards

Flashcards covering the key concepts and topics from the Edexcel Geography A-level Tectonic Processes and Hazards notes.

What is a hazard?

A potential threat to human life and property.

What causes natural hazards?

Climatic processes causing hydro-meteorological hazards or land processes causing geophysical hazards.

Where do Geophysical hazards occur?

Near plate boundaries are where they occur.

What is assumed to cause Earthquakes near the middle of plates?

Plates have pre-existing weaknesses which become reactivated, forming seismic waves.

What are Volcanic hotspots?

A localised area of the lithosphere with an unusually high temperature due to the upwelling of hot molten material from the core.

Where do the most powerful earthquakes usually occur?

Convergent or conservative boundaries.

What is an OFZ (Oceanic Fracture Zone)?

A belt of activity through the oceans and along the mid-ocean ridges through Africa, the Red Sea, the Dead Sea

What is CFZ (Continental Fracture Zone)?

A belt of activity along the mountain ranges from Spain through the Alps to the Middle East and to the Himalayas.

What is the trend for the total number of recorded hazards since 1960?

It is increasing.

What is the trend for the number of fatalities caused during hazards since 1960?

It has decreased, with spikes during mega disasters.

What is the trend for the total number of people being affected by tectonic hazards since 1960?

It is increasing due to population growth.

What is the trend for economic costs associated with hazards and disasters since 1960?

It has increased significantly, partly due to increases in development and insurance policies.

What does reporting disaster impacts depend on?

Depends on looking at direct deaths versus indirect deaths from diseases after the disaster.

Why is location important in reporting disaster impacts?

Rural and isolated areas are hard to reach, and data may be difficult to collect in densely populated areas.

Why can different sources quote different numbers of deaths and injuries?

Different methods used by different organisations may lead to different numbers.

What are the four sections of the Earth's structure?

Crust, Mantle, Outer Core, Inner Core.

What causes the core's high temperature?

Radioactive elements in the core decay.

What happens at plate boundaries?

Plates move towards each other (destructive), away from each other (constructive), or parallel to each other (conservative).

What occurs at Destructive plate boundaries (Continental and oceanic)?

Denser oceanic plate subducts below the continental plate, creating a deep ocean trench, explosive volcanoes, and fold mountains.

What occurs at Constructive plate boundaries (Oceanic and oceanic)?

Magma rises in between the gap left by the two plates separating, forming new land when it cools, less explosive underwater volcanoes, and sea floor spreading.

What occurs at Constructive plate boundaries (Continental to continental)?

Any land in the middle of the separation is forced apart, causing a rift valley where volcanoes form where the magma rises. Eventually the gap will most likely fill with water and separate completely from the main island.

What occurs at Conservative plate boundary?

Parallel plates move in different directions or at different speeds, building up pressure. Fault lines can occur where the ground is cracked by the movement

What type of rock does Oceanic crust consist of?

High density of rock, mainly basalt, thin, newly created.

What type of rock does Continental crust consist of?

Low density of rock, mainly granite, thick, old.

What is Mantle Convection?

Radioactive elements in the core of the Earth decay which produce a lot of thermal energy. This causes the lower mantle to heat up and rise, as the magma rises it cools down and becomes more dense and begins to sink back down to the core. These are convection currents.

What is Slap Pull?

Old oceanic crust (which is the most dense plate) will submerge into the mantle. This pulling action drags the rest of the plate with it

What is the focus (or hypocentre) of an Earthquake?

The point underground where the earthquake originates from.

What is the epicentre of an Earthquake?

The area above ground that is directly above the focus.

What is Soil Liquefaction?

Affects poorly compacted sand and silt. Water moisture within the soil separates from the soil particles and rises to the surface, causing the soil to behave like a liquid.

What is Landslides?

During an earthquake, the shaking can weaken or damage cliff faces, hills and snow material which causes Unconsolidated material or loose rocks to collapse

What is a Tsunamis?

The shaking of an oceanic crust during an earthquake causes all of the water above this plate is displaced causing it to travel fast but with a low amplitude (height).

What are Lava flows?

Streams of lava that have erupted onto the Earth’s surface.

What are Pyroclastic flows?

A mixture of hot dense rock, lava, ash and gases which move very quickly along the surface of the Earth

What are Tephra and ash flows?

Pieces of volcanic rock and ash are blasted into the air. This can cause serious damage to buildings.

What are Volcanic gases?

Gases like sulphur dioxide and carbon monoxide are released into the atmosphere. Due to their potency, volcanic gases can travel long distances.

What are Lahars?

Combination of rock, mud and water which travel quickly down the sides of volcanoes. These can occur when the heat of the eruption causes snow and ice to melt or alternatively when an eruption coincides with heavy rainfall.

What is a Jokulhaup?

Snow and ice in glaciers melt after an eruption which causes sudden floods that are very dangerous .

What is Acid rain?

Caused when gases such as sulfur dioxide are released into the atmosphere.

What is a Disaster?

A serious disruption of the functioning of a community or society involving human, material, economic and environmental losses which exceeds the ability of the affected community or society to cope using its own resources.

What occurs during Stage 1 - Relief (hours-days) of the Park Model?

Immediate local response - medical aid, search and rescue and Immediate appeal for foreign aid - the beginnings of global response.

What occurs during Stage 2 - Rehabilitation (days-weeks) of the Park Model?

Services begin to be restored, Temporary shelters and hospitals set up, Food and water distributed, Coordinated foreign aid - peacekeeping forces etc.

What occurs during Stage 3 - Reconstruction (weeks-years) of the Park Model?

Restoring the area to the same or better quality of life, Area back to normal - ecosystem restored, crops regrown, Infrastructure rebuilt and Mitigation efforts for future event.

What is Physical Vulnerability?

Individuals live in a hazard-prone area, with little protection naturally or through mitigation.

What is Economic Vulnerability?

People risk losing their employment, wealth or assets during a hazard.

What is Social Vulnerability?

Communities are unable to support their disadvantaged or most vulnerable, leaving them at risk to hazards.

What is Knowledge Vulnerability?

Individuals lack training or warning to know the risks of a hazard or how to safely evacuate.

What is Environmental Vulnerability?

A community’s risk to a hazard is increased due to high population density in the area.

What is Frequency on a Hazard profile?

How often it happens.

What is Magnitude on a Hazard profile?

How extensive an area the event could affect

What is Duration on a Hazard profile?

How long the event lasts

What is Speed of onset on a Hazard profile?

How much warning time before event occurs

What is Spatial Predictability on a Hazard profile?

The predictability of where would be affected.

What is Volcanic Explosivity Index (VEI)?

Measures the relative explosiveness of a volcanic eruption, Based on the height of ejected material and duration of eruption.

What is The Modified Mercalli Scale?

Measures the destructiveness of an earthquake.

What is the Moment Magnitude Scale?

Measures the amount of energy released in earthquake.

What is the Richter Scale?

Measures the amplitude of the waves produces during an earthquake

What is the Hazard Management Cycle?

Outlines the stages of responding to events , showing how the same stages take place after every hazard.

What is Preparedness in the Hazard Management Cycle?

Being ready for an event to occur (public awareness, education, training)

What is Response in the Hazard Management Cycle?

Immediate action taken after event (evacuation, medical assistance, rescue)

What is Recovery in the Hazard Management Cycle?

Long-term responses (restoring services, reconstruction)

What is Mitigation in the Hazard Management Cycle?

Strategies to lessen effects of another hazard (barriers, warning signals developed, observatories)

Give some examples of micro approaches on how Modify the Event during earthquake?

Public buildings like hospitals, police stations and other vital infrastructure are emphasized, Schools and factories strengthened to help shelter people and Some improvements to private houses

Give some examples of how Modify the Event during Tsunami?

Tsunami walls which work for a given amplitude and threshold of wave and Replanting coasts with mangroves and coastal forestry which dissipates energy from waves

Give some examples of how Modify the Event during Volcanoes?

Diverting flows of lava and Reinforce house roofs to withstand large deposits of ash

What are some advantages of Community Preparedness and Education?

Low cost and often implemented by NGOs and Can save lives through small actions

Give an example of Short term aid during Modification of Loss.

Search and rescue and also food, water, aid and shelter

Give an example of Long term aid during Modification of Loss.

Reconstructions plant to rebuild an area and improve resilience

Give an example of Insurance during Modification of Loss.

Compensation to replace losses

What does The Risk Poverty Nexus state?

States that poverty is both a contributing factor and consequence of a natural hazard and suggests that a positive feedback mechanism can cause further economic loss for already poor countries.

What is Asset inequality?

Relates to housing and security of tenure and also agricultural productivity.

What is Political inequality?

Where certain groups of people, usually the wealthy and elite, hold quite a lot of power and political influence.

What is Social status inequality?

Often directly linked to space and has a bearing on other dimensions of inequality, including the ability of individuals and groups to secure regular income and access services.

What is Entitlement inequality?

Refers to unequal access to public services and welfare systems as well as inequalities in the application of rule of law.

How does Planning help?

Education and community preparation programmes raise awareness and teach people how to prepare, evacuate and act when a disaster strikes.

What are the Characteristics of Tectonic Mega-Disasters?

Large scale disaster affecting a large spatial areas or large population, problems in effective management to minimise the impacts and The scale of the impact may require international support and aid.