AQA Geography: The Challenge of Natural Hazards

Comprehensive vocabulary flashcards covering AQA Unit 1a: The Challenge of Natural Hazards, including Earth structure, plate tectonics, case studies of the 2010 Chile and 2015 Nepal earthquakes, tropical storms (Hurricane Irma), extreme UK weather (Boscastle flood), and climate change causes, evidence, mitigation, and adaptation.

Natural Hazards

Physical events such as earthquakes, volcanic eruptions, and tropical storms that have the potential to cause damage to humans and property.

Hazard Risk

The likelihood of being affected by a natural hazard, influenced by factors including population growth, global climate change, deforestation, and wealth (with LICs being particularly vulnerable).

Oceanic Crust

A dense, thin, and geologically young section of the Earth's outer crust.

Continental Crust

A thicker, older, and less dense section of the Earth's crust that forms the landmasses.

Constructive Plate Margin

A plate boundary where tectonic plates pull apart from one another, allowing hot magma to rise, creating shield volcanoes and usually small earthquakes (e.g., Iceland).

Destructive Plate Margin

A boundary where plates move towards each other, such as an oceanic plate subducting under a continental plate or two continental plates colliding, causing intense friction, pressure release, violent earthquakes, and composite volcanoes.

Conservative Plate Margin

A boundary where tectonic plates slide past each other; friction causes plates to catch, and released pressure generates earthquakes without creating volcanic activity (e.g., the San Andreas Fault).

Primary Effects

Direct impacts that happen immediately as a result of an event (such as ground shaking in an earthquake), including destroyed buildings, killed or injured people, and broken infrastructure.

Secondary Effects

Indirect impacts that happen subsequent to and as a result of primary effects, including tsunamis, landslides, fires from ruptured gas mains, contaminated water supplies, and economic decline.

Immediate Responses

Short-term actions taken immediately during and after a disaster, focusing on search and rescue, treating the injured, and keeping survivors alive by providing emergency food, water, medical care, and shelter.

Long-Term Responses

Re-building and reconstruction efforts undertaken months and years after a disaster to return people's lives to normal and reduce future risk through stricter building codes and monitoring systems.

Chile Earthquake (27 February 2010)

A magnitude 8.8 earthquake on a destructive margin (Nazca Plate subducting beneath the South American Plate) that caused 500 deaths, injured 12,000, destroyed 220,000 homes, and caused an estimated US$30$ billion in damage.

Route 5 North-South Highway

An important transport corridor in Chile that received temporary repairs within 24 hours of the 2010 earthquake, enabling emergency aid to be transported from Santiago to affected regions.

Nepal Earthquake (25 April 2015)

A shallow magnitude 7.9 earthquake (15 km deep) occurring where the Indo-Australian Plate collides with the Eurasian Plate at a rate of 45 mm per year, killing 9,000 people, injuring 20,000, destroying 3 million homes, and causing US$5$ billion in damage.

Dharahara Tower

A landmark historic monument in Kathmandu that collapsed during the April 2015 Nepal earthquake.

Kali Gandaki River

A river in Nepal that was blocked by a massive landslide 140 km (90 miles) northwest of Kathmandu following the 2015 earthquake, necessitating evacuations due to flood risks.

1934 Kathmandu Earthquake

A historic earthquake that struck the Kathmandu valley in 1934, killing over 10,000 people and illustrating Nepal's recurring pattern of large earthquakes roughly every 80 years.

Coriolis Effect

The deflection of wind paths caused by the rotation (turning) of the Earth, which makes winds curve and causes tropical storms to spin.

Tropical Storm

An intense low-pressure storm system occurring in low latitudes between $5^\natural$ and $30^\natural$ north and south of the equator, requiring sea surface temperatures above $27^\natural\text{C}$.

Eye of the Storm

The calm, central core of a tropical storm where cold, dry air sinks, resulting in clear skies and calm conditions.

Hurricane Irma (September 2017)

A major tropical storm featuring 185 mph winds and a 10 m storm surge that caused 92 deaths, major flooding in Florida, severe power outages across Puerto Rico, and US$50$ billion in damage.

Boscastle Flood (August 2004)

A flash flood event in Cornwall where 130 mm of rain fell in one storm (exceeding the average August total of 73 mm), resulting in 50 washed away cars, £500m in repair costs, and a massive airlift operation that saved over 50 people with 0 fatalities.

Milankovitch Cycles

Natural cyclical variations in the Earth's orbit and axial tilt that alter the amount and distribution of solar energy reaching the Earth's surface over long periods.

Sunspot Cycles

Cyclical variations in solar output that reach a maximum every 11 years, altering the solar radiation received by Earth.

Ice and Sediment Cores

Cores extracted from polar ice sheets (analyzing trapped atmospheric gases spanning up to 400,000 years) and deep ocean sediments (analyzing fossilized organisms spanning 5 million years) to reconstruct past climate variations.

Pollen Analysis

The study of preserved plant pollen trapped in geological sediment layers to determine past vegetation distribution and infer historic climatic conditions.

Dendrochronology

The study of annual growth rings in trees to reconstruct past temperature and precipitation patterns over the last 10,000 years, where thicker rings reflect warmer and wetter growing conditions.

Climate Change Mitigation

Strategies aimed at reducing or preventing the emission of greenhouse gases or removing them from the atmosphere, such as alternative renewable energy, afforestation, carbon capture and storage, and international agreements like the 2015 Paris Agreement.

Climate Change Adaptation

Strategies designed to adjust human activities and infrastructure to cope with the unavoidable impacts of climate change, such as altering crop varieties, managing water with desalination plants, and constructing defenses like sea walls or the Thames Flood Barrier.