glossary Flashcards
Aftershocks
a less-powerful earthquake which follows a more-powerful
earthquake – a result of the fault ‘settling’ into its new position
Aid
short-term help – such as food, given in emergency, or long-term help
– such as training in health care
Atmosphere
the layer of gases above the Earth’s surface
Aurora borealis
magnetic force field where radiation from space hits Earth’s
magnetosphere and lights up the sky – also known as the
‘northern lights’
Basalt
a dark-coloured volcanic rock. Molten basalt spreads rapidly and is
widespread. About 70% of the Earth’s surface is covered in basalt
lava flows
Climatologist
a scientist who is an expert in climate and climate change
Collision zones
where two tectonic plates collide – forming mountains fold mountains
like the Himalayas
Conservative plate
boundary
where two tectonic plates are sliding alongside each other, in the
same or different directions
Continental crust
the part of the Earth’s crust that makes up land, on average
30-50 km thick
Convection currents
currents which transfer heat from one part of a liquid or gas to
another.
Convergent plate
boundary
where two tectonic plates collide
Core
the centre of Earth, believed to be solid inside with a hot liquid
outer core
Coriolis force
a strong force created by the Earth’s rotation. It can cause storms,
including hurricanes
Cumulonimbus clouds
tall clouds created by the condensation of water vapour
Divergent plate
boundary
where two tectonic plates are moving away from each other
Economic impacts
impacts on the wealth of an area
Enhanced greenhouse
effect
the increased effectiveness of the greenhouse effect, believed to be
the cause of recent global warming
Epicentre
the point on the ground directly above the focus (centre) of an
earthquake
Evacuate
when people move from a place of danger to a safer place
Eye of the storm
the centre of a storm, consisting of calm, descending dense air
Ferrel cell
part of the global circulation model, where Earth’s atmosphere
consists of descending cool, dry air
Focus
the point of origin of an earthquake
Friction
the force which resists the movement of one surface over another
Geothermal
heat from inside the Earth
Glacial
a cold period of time during which the Earth’s glaciers expanded widely
Global circulation
model
a theory that explains how the atmosphere operates in a series of
three cells each side of the Equator
Greenhouse effect
the way that gases in the atmosphere trap heat from the sun. Like the glass
in a greenhouse – they let heat in, but prevent most of it from escaping
Greenhouse gas
gases like carbon dioxide and methane that trap heat around the
Earth, leading to global warming
Gulf stream
a warm ocean current that begins in the Gulf of Mexico and is blown
northeast across the North Atlantic
Hadley cell
the largest section of the global circulation model, found above the
tropics and caused by the heating and cooling of Earth’s atmosphere
Hot spots
columns of heat in Earth’s mantle found in the middle of a tectonic plate
Hurricane
the term given to a tropical cyclones in the USA and Caribbean
Ice cores
columns of ice that are extracted from ice sheets and used to
reconstruct temperature patterns
Interglacial
a long period of warmer conditions between glacials
Inter-tropical
Convergence Zone
(ITCZ)
a narrow zone of low pressure near the Equator where northern and
southern air masses converge
Lava
melted rock that erupts from a volcano
Lava flows
lava flows at different speeds, depending on what it is made of. Lava
flows are normally very slow and not hazardous but, when mixed with
water, lava can flow very fast and be dangerous
Levée
embankments found on either side of a river, formed naturally by regular
flooding or built up by people to protect the area against flooding
Lithosphere
the cool and brittle uppermost layer of the Earth. It includes the very
top of the mantle and, above this, the crust
Magma
melted rock below the Earth’s surface. When it reaches the surface
it is called lava
Magnetosphere
a huge invisible magnetic field that surrounds Earth, protecting it
from harmful radiation from space and the sun
Magnitude
of an earthquake (how much the ground shakes), an expression of
the total energy released
Mantle
the middle layer of the Earth. It lies between the crust and the core
and is about 2900 km thick. Its outer layer is the asthenosphere.
Below the asthenosphere it consists mainly of solid rock
Meteorites
fragments of rock and metal that fall to Earth from space
Milankovitch cycles
the three long-term cycles in the Earth’s orbit around the sun.
Milankovitch’s theory is that glacials happen when the three cycles
match up in a certain way
North Atlantic drift
a warm ocean current that branches off from the Gulf Stream into
the North Atlantic Ocean
Ocean currents
permanent or semi-permanent large-scale horizontal movements of
the ocean waters
Oceanic crust
the part of the Earth’s crust which is under the oceans, usually
6-8 km thick
Pangea
a supercontinent consisting of the whole land area of the globe
before it was split up by continental drift
Plate boundaries
where tectonic plates meet. There are three kinds of boundary a)
divergent – when two plates move apart b) convergent – when two
plates collide c) conservative – when two plates slide past one
another
Plumes
upwelling of molten rock through the asthenosphere to the
lithosphere
Polar cell
sections of the Earth’s atmosphere found above the North and
South Poles, consisting of descending cold, dry air
Polar desert
areas in Antarctica and the Arctic ice sheet that have dry and cold
climate conditions
Predict
saying that something will happen in the future. A scientific
prediction is based on statistical evidence
Primary effects
the direct impacts of event, usually occurring instantly
Probability
the chance of an event happening
Pyroclasts
fragments of volcanic material that is thrown out during explosive
eruptions
Quaternary
the last 2.6 million years, during which there have been many glacials
Radioactive decay
atoms of unstable elements release particles from their nuclei and
give off heat
Refugees
people who are forced to move due to natural hazards or war
Relief effort
help given by organisations or countries to help those facing
an emergency
Richter scale
a scale for measuring the magnitude of earthquakes
Risk zone
areas assessed upon the likelihood of hazardous events happening,
such as storm surges
Saffir-Simpson hurricane
scale
a scale that classifies hurricanes into five different categories
according to their wind strength
Secondary effects
the indirect impacts of an event, usually occurring in the hours, weeks,
months or years after the event
Seismometer
a machine for recording and measuring an earthquake using the
Richter scale
Social impacts
the impacts of an event upon people
Solar insolation
the Sun’s energy
Storm surge
a rapid rise in the level of the sea caused by low pressure and
strong winds
Stratosphere
the layer of air 10-50km above the Earth’s surface. It is above the
cloudy layer we live in, the troposphere
Stratovolcano
type of volcano characterised by steep sides, also known as a
composite cone
Subduction
describes oceanic crust sinking into the mantle at a convergent plate
boundary. As the crust subducts, it melts back into the mantle
Sunspots
a dark patch that occasionally appears on the surface of the Sun
Tectonic hazards
natural events caused by movement of the Earth’s plates that affect
people and property
Tectonic plate
the Earth’s surface is broken into large pieces, like a cracked
eggshell. The pieces are called tectonic plates, or just plates
Thermal expansion
as a result of heating, expansion occurs. When sea water warms
up, it expands
Trade winds
easterly winds that blow from high to low pressure, towards the
Equator
Tree rings
the growth of a tree can be seen in its rings, each representing a
year’s growth. Scientists use these to examine past climate conditions
Tropical cyclone
an area of low pressure with winds moving in a spiral around a calm
central point called the eye of the storm – winds are powerful and
rainfall is heavy
Tropics
regions either side of the Equator where the Sun moves directly
overhead from its farthest point in the North and the South
Tsunami
earthquakes beneath the sea bed generate huge waves that travel up
to 900km/h
Typhoon
term given to a tropical cyclone in the western North Pacific
Volcanic Explosivity
Index (VEI)
measures the explosiveness of volcanic eruptions on a scale of 1 to 8
