AQA A-Level Geography - Hazards Flashcards

Flashcards about AQA a-level GEOGRAPHY PAPER 1 Hazards

What is a hazard?

A hazard is the threat of significant loss of life, severe impact on life, or property damage caused by an event, which puts people at risk.

What is a disaster?

A disaster occurs when a hazard leads to widespread destruction.

What are primary impacts of natural hazards?

Primary impacts happen immediately, caused by events such as ground shaking or extreme winds (e.g., homes collapse, damage to infrastructure).

What are secondary impacts of natural hazards?

Secondary impacts are the after-effects resulting from the primary impacts (e.g., disease outbreaks, cut-off water/power supplies, economic downturns).

What is the primary human response to hazards?

Risk reduction, including securing property locally and coordinating rescue efforts globally.

What are the stages of the Hazard-Management Cycle?

Preparedness, Response, Recovery, and Mitigation.

What are the phases of the Park Model of Disaster Response?

Relief, Rehabilitation, and Reconstruction.

What are the Hazard categories?

Geophysical, Atmospheric, and Hydrological.

What are the key approaches to hazard response?

Fatalism, Prediction, and Adaptation.

What are the 3 key ideas behind tectonic plate movement?

Mantle convection, Ridge push, and Slab pull

What are the two types of crust?

Oceanic crust (sima) and Continental crust (sial)

What evidence confirmed sea-floor spreading?

Palaeomagnetism confirmed symmetrical magnetic field reversals.

What is ridge push?

Cool oceanic lithosphere is denser and gradually subsides into the mantle below it. Gravity makes the rigid lithospheric plates slide down the hot, raised asthenosphere below mid-ocean ridges.

What is slab pull?

Coolest and densest section of a tectonic plate produces a downward force along the rest of the plate, subducts into the mantle at destructive plate margins.

What occurs at constructive plate margins?

Plates separate, new crust is formed when magma rises to the surface.

What geological features are created at constructive margins?

Mid-ocean ridges and Rift valleys.

What occurs at destructive plate margins?

Plates collide. There are three types: Oceanic-continental, Oceanic-oceanic, and Continental-continental.

What occurs at conservative plate margins?

Plates slide past each other. No subduction occurs, so no crust is created or destroyed, but stress build-up causes shallow-focus earthquakes.

What causes hot spots?

Magma plumes rise through the lithosphere where the crust is thin or weak.

Where does most volcanic activity occur?

At plate margins.

What does the Volcano Explosivity Index (VEI) measure?

Eruptions on a scale from 0 to 8.

How can scientists predict volcanic eruptions?

Increased seismic activity, Ground swelling or deformation, Increased emission of gases, and Increased steaming or fumarolic activity.

What are lahars?

Volcanic mudflows, among the deadliest volcanic hazards. They can be hot or cold, triggered by eruptions, melting glaciers, or heavy rain mixing with ash.

What are fissure eruptions?

Release basic lava, forming extensive lava plateaus.

What are shield volcanoes?

Broad with shallow sides, formed from basaltic lava. Common at constructive plate margins and hot spots, they produce gentle eruptions.

What are acid dome volcanoes?

Steep, convex cones formed from viscous, silica-rich lava. They erupt explosively, producing deadly pyroclastic flows.

What are composite volcanoes (stratovolcanoes)?

Alternating layers of ash, tephra, and lava. They have a conical shape but often develop secondary cones and fissures.

What are calderas?

Form when a violent eruption empties the magma chamber, causing the volcano to collapse into a massive crater.

What were the impacts of the Eyjafjallajökull, Iceland (2010) eruption?

Severe flooding as meltwater washed away roads, ash deposits ruined farming, supply chains were disrupted, and European airspace was closed for 6 days.

What were the impacts of the Mount Merapi, Java, Indonesia (2010) eruption?

353 deaths, displacement of 350,000 people, lahar and pyroclastic flows devastated homes, and major aviation disruption.

What happened during the Montserrat, Caribbean 1995- present eruption?

Eruptions from Chances Peak led to the evacuation of Plymouth, a catastrophic eruption in June 1997 killed 19 people and destroyed the airport, and further eruptions continued to cause evacuations.

What are anthropogenic earthquakes?

Those caused by human activities, e.g. fracking or constructing a new reservoir.

What is the focus of an earthquake?

The point where the rocks fracture. Sends a series of seismic shockwaves to the surface.

What is the epicenter of an earthquake?

The point directly above the focus. Experiences the most intense ground shaking.

What are the types of seismic waves?

Primary (P) waves, Secondary (S) waves, and Surface Love (L) and Rayleigh (R) waves.

What are tsunamis?

Giant waves caused by the sudden displacement of a large volume of water, triggered by large earthquakes occurring on or near the ocean floor.

What mitigation techniques can be used for earthquakes?

Earthquake-resistant construction, Geographic Information Systems (GIS) to prepare hazard maps, and Public education.

What are factors affecting the impact of an earthquake?

Magnitude, depth, surface geology, population density, building design, and time of day.

What is the Moment Magnitude Scale (Mw)?

Measures earthquake magnitude based on the earthquake's seismic moment using a logarithmic scale.

What is the Modified Mercalli Intensity Scale?

Measures earthquake damage using observations of the earthquake’s impact.

What were the primary impacts of the Port-au-Prince earthquake, Haiti, 2010?

Over 230,000 deaths, 50% of Port-au-Prince buildings collapsed, over 180,000 homes were damaged, and infrastructure was destroyed.

What were the secondary impacts of the Port-au-Prince earthquake, Haiti, 2010?

Challenges in accessing food, water, sanitation, and healthcare, a weakened government, general lawlessness, and a cholera outbreak.

What were the primary impacts of the Indian Ocean tsunami, 2004?

Up to 300,000 fatalities, infrastructure destroyed, coastal settlements devastated, and vegetation/topsoil stripped up to 800m inland.

What were the secondary impacts of the Indian Ocean tsunami, 2004?

Widespread homelessness, devastated economies, and water supplies and soils contaminated by salt water.

What were the primary effects of the Tohoko earthquake, japan, 2011?

Ground shaking caused buildings to collapse, tsunami swept inland

What are sustained wind speeds in a tropical storm?

In excess of 120km/h (75mph) – can be 500km in diameter

What factors affect the distribution of tropical storms?

Oceans, High temperatures, Atmospheric instability, Rotation of the Earth, and Uniform wind direction at all levels.

What conditions lead to the formation and development of a tropical storm?

Warm, moist air rises rapidly, creating a central vortex, Cumulonimbus clouds form, Condensation releases latent heat that powers the storm

What are the effects of tropical storms?

Strong winds, Storm surges, Coastal and river flooding, and Landslides.

What mitigation strategies are used in response to tropical storms?

Preparedness, Prevention, Adaptation, Structural responses, and Disaster aid.

What is a wildfire?

Generic name used for an uncontrolled rural fire (bushfires in Australia, brushfires in North America)

What are the causes of wildfires?

Human actions (e.g., discarded cigarettes and campfires). Heat transfer processes (radiation, conduction, convection).

What are the impacts of wildfires?

Social, Economic, Environmental and Political

What are the response strategies for wildfires?

Preparedness, Prevention, Mitigation and Adaptation