GCSE Geography: Natural Hazards Flashcards

Question 1

Define Natural Hazard.

Accepted Answer

A natural event, such as an earthquake or storm, that has the potential to threaten people's lives or damage property and the environment. It only becomes a disaster when it harms people.

Question 2

Define Hazard Risk.

Accepted Answer

The probability that a hazard will affect people, and how badly. Risk rises with population density, poverty, urbanisation and exposure, and falls with good preparation, monitoring and strong buildings.

Question 3

What is Urbanisation?

Accepted Answer

The growth of the proportion of people living in towns and cities. It can raise hazard risk because more people and buildings are packed into one place, especially if building standards are poor.

Question 4

Define Plate Tectonics Theory.

Accepted Answer

The idea that the Earth's crust is split into large moving slabs called plates, which float on the mantle. Most earthquakes and volcanoes occur where plates meet at plate margins.

Question 5

Define Convection Currents.

Accepted Answer

Slow circular movements in the mantle, where hot rock rises from near the core, cools, spreads sideways and sinks again. They help drag the plates above them.

Question 6

Define Constructive Margin.

Accepted Answer

A plate margin where two plates move apart. Magma rises into the gap and cools to form new crust, causing gentle volcanic eruptions and frequent, shallow earthquakes.

Question 7

Define Destructive Margin.

Accepted Answer

A plate margin where an oceanic plate is forced beneath a continental plate. It produces deep ocean trenches, explosive volcanoes and powerful earthquakes as crust is destroyed.

Question 8

Define Conservative Margin.

Accepted Answer

A plate margin where two plates slide past each other, or move in the same direction at different speeds. Friction builds stress that releases as earthquakes, but no volcanoes form.

Question 9

What is Subduction?

Accepted Answer

The process where a denser oceanic plate sinks beneath a lighter plate at a destructive margin. The sinking crust melts, feeding magma to volcanoes above and triggering earthquakes as it grinds downwards.

Question 10

Define Composite Volcano.

Accepted Answer

A steep-sided volcano built from alternating layers of ash and lava, found at destructive margins. Its thick, sticky magma traps gas and causes violent, explosive eruptions.

Question 11

What is Focus?

Accepted Answer

The point underground where an earthquake begins, where rock breaks and energy is first released. Seismic waves spread outwards in all directions from this point.

Question 12

What is Epicentre?

Accepted Answer

The point on the Earth's surface directly above the focus of an earthquake. Shaking is usually strongest here and generally weakens with distance from this point.

Question 13

Define Richter Scale.

Accepted Answer

A logarithmic scale that measures the magnitude of an earthquake from seismometer readings. Each whole number represents about ten times more ground shaking than the number below.

Question 14

Define Primary Effects.

Accepted Answer

The immediate damage caused directly by a hazard as it happens, such as collapsed buildings, broken roads and deaths from falling debris or the force of the storm.

Question 15

Define Secondary Effects.

Accepted Answer

The knock-on damage that follows after a hazard, caused by the primary effects. Examples include fires, tsunamis, landslides, disease, food shortages and loss of jobs.

Question 16

Define Immediate Responses.

Accepted Answer

Actions taken in the hours and days after a hazard to save lives and meet urgent needs, such as search and rescue, first aid, emergency shelter, food and clean water.

Question 17

Define Long-Term Responses.

Accepted Answer

Actions taken over months and years to recover after a hazard, such as rebuilding homes, repairing roads and utilities, reviving the economy and improving future preparation.

Question 18

Define Chile Earthquake 2010.

Accepted Answer

A magnitude 8.8 earthquake on a destructive margin where the Nazca Plate sinks under the South American Plate. Around 500 people died, helped by strict building codes and effective emergency services.

Question 19

Define Nepal Earthquake 2015.

Accepted Answer

A magnitude 7.8 earthquake where the Indian Plate pushes into the Eurasian Plate. About 9,000 people died as weak buildings collapsed, and remote mountain villages were hard for rescuers to reach.

Question 20

What is Monitoring?

Accepted Answer

Using instruments to detect warning signs of a hazard. At volcanoes, scientists track earthquakes, swelling slopes and gas emissions, which can help forecast an eruption and evacuate people in time.

Question 21

What is Protection?

Accepted Answer

Reducing damage by designing for the hazard. In earthquake zones this includes cross-bracing, rubber shock absorbers in foundations and automatic gas shut-off valves, so buildings flex instead of collapsing.

Question 22

Define Planning (Hazard Management).

Accepted Answer

Preparing in advance by controlling land use, marking evacuation routes and running drills. It aims to limit the number of people and critical buildings placed in the most dangerous areas.

Question 23

Define Global Atmospheric Circulation.

Accepted Answer

The large-scale movement of air around the Earth, driven by uneven heating from the sun. It is organised into cells that create pressure belts and the main surface wind patterns.

Question 24

Define Trade Winds.

Accepted Answer

Surface winds that blow from about 30 degrees latitude towards the equator, from the north-east in the northern hemisphere. They steer tropical storms westward across the oceans.

Question 25

Define Tropical Storm.

Accepted Answer

A powerful rotating storm with winds above 74 mph, forming over warm oceans. Known as hurricanes, typhoons or cyclones depending on location, it brings heavy rain, storm surges and high winds.

Question 26

Define Coriolis Effect.

Accepted Answer

The deflection of moving air caused by the Earth's rotation. It makes tropical storms spin, and is too weak near the equator, so storms rarely form closer than about 5 degrees.

Question 27

Define Eye of a Storm.

Accepted Answer

The calm centre of a tropical storm, with light winds, clear skies and sinking air. It is surrounded by the eye wall, where the strongest winds and heaviest rain occur.

Question 28

Define Storm Surge.

Accepted Answer

A rise in sea level, caused by low pressure and strong winds pushing water towards the coast. It often causes more deaths in a tropical storm than the winds themselves.

Question 29

Define Typhoon Haiyan 2013.

Accepted Answer

A powerful typhoon that hit the Philippines in November 2013. Over 6,000 people died, mostly from a storm surge, and millions were made homeless. Aid agencies provided shelter, food and clean water.

Question 30

Define Somerset Levels Floods 2013-14.

Accepted Answer

Flooding after one of the wettest winters on record in southern England. Villages were cut off for weeks, farmland stayed underwater and later management included dredging the rivers Parrett and Tone.

Question 31

Define Quaternary Period.

Accepted Answer

The most recent geological period, covering roughly the last 2.6 million years to the present. It is marked by repeated cold glacial periods and warmer interglacial periods.

Question 32

Define Ice Cores.

Accepted Answer

Long cylinders of ice drilled from ice sheets. Trapped air bubbles and chemical records show past temperatures and carbon dioxide levels, giving evidence of climate change over hundreds of thousands of years.

Question 33

Define Orbital Changes.

Accepted Answer

Natural variations in the Earth's orbit and tilt over tens of thousands of years that change how much sunlight reaches different parts of the planet. They help explain glacial and interglacial cycles.

Question 34

Define Enhanced Greenhouse Effect.

Accepted Answer

Extra warming caused by human activities adding greenhouse gases, such as carbon dioxide from burning fossil fuels and methane from farming. More heat is trapped in the atmosphere than naturally.

Question 35

What is Mitigation?

Accepted Answer

Actions that reduce the causes of climate change by cutting greenhouse gas emissions or removing carbon dioxide from the air. It tackles the problem at its source.

Question 36

What is Adaptation?

Accepted Answer

Actions that help people and places cope with the effects of climate change, rather than reducing its causes. These include changing farming, managing water supply and building defences against rising seas.

Question 37

Define Carbon Capture.

Accepted Answer

A mitigation technology that traps carbon dioxide from power stations and factories before it enters the air, then stores it deep underground in rock formations.