HAZARDS: key terms Flashcards
what is a NATURAL HAZARD?
a perceived event that threatens life, the built environment and the natural environment, occurring in the lithosphere, the atmosphere and the hydrosphere
what is RISK?
the exposure of people to a hazardous event that places potential threat to them, their possessions and their built environment
what is VULNERABILITY?
the potential for loss
what is FATALISM?
such hazards are natural events which are part of living in the area
what is ADAPTATION as a hazard perception?
people seeing they can prepare and survive hazards by prediction, prevention and protection
what is FEAR?
people feeling so vulnerable that they move away to a perceived safe area
what is RESILIENCE?
the sustained ability to utilise available resources to respond to, withstand and recover from the effects of natural hazards
what is INTEGRATED RISK MANAGEMENT?
a management technique to confront the natural hazard by considering the social, economic and political factors, incorporating:
- hazard identification
- risk analysis
- establishing priorities
- treating and reducing risk
- developing public awareness
- monitoring and reviewing
what is PREDICTION?
the ability to to give warnings so action can be taken to reduce the impact of a hazard event
what is DISTRIBUTION?
the area affected by the hazard, or where the hazard is found
what is FREQUENCY?
the distribution of a hazard through time
what is MAGNITUDE?
the assessment of the size of the impacts of a hazard event
what is a PRIMARY EFFECT?
events resulting directly from a hazard event
what is a SECONDARY EFFECT?
events resulting from the primary effects
what is a HAZARD?
a threat posed to people by the natural environment
what is a DISASTER?
a hazards that causes severe harm to a community
what is PERCEPTION?
the way in which an individual or group views the threat of a hazard
what is MITIGATION?
long-term action taken to reduce or eliminate the risk to life and property
what is SOIL LIQUEFACTION?
the process by which saturated, unconsolidated soil is converted into a suspension during an earthquake
what is the ASTHENOSPHERE?
the part of the mantle below the lithosphere that is hotter and more fluid
what is the LITHOSPHERE?
the crust and upper mantle
what is a CONSERVATIVE PLATE MARGIN?
two tectonic plates move past each other
what is a CONSTRUCTIVE PLATE MARGIN?
two tectonic plates move apart to generate new crust
what is a DESTRUCTIVE PLATE MARGIN?
two plates converge, destroying crust
what is PALEOMAGNETISM?
the study of the polarity of ancient magnetic particles in rocks
what is a RIFT VALLEY?
a long, deep valley in the centre of a spreading ridge, formed between parallel faults where a block of crust has sunk
what is the theory of SEA-FLOOR SPREADING?
the theory that the ocean floor is moving away from the mid-oceanic ridge across the deep ocean basin to disappear beneath continents and island arcs
what is a TECTONIC PLATE?
one of a series of rigid section of the crust that floats on the upper mantle and move relative to each other
what is SLAB PULL?
the subducted oceanic crust creates suction, pulling more down
what is RIDGE PUSH (gravitational sliding)?
ridges form, and gravity acts on them as they reach high elevations, pushing the plates down and apart
what is PRIMORDIAL HEAT?
heat left over from the formation of the Earth
what is RADIOGENIC HEAT?
heat produced when radioactive isotopes decay, such as Uranium-238
what is CONTINENTAL DRIFT?
the theory that, 300 million years ago, there was one giant continent: Pangaea, which split in Laurasia and Gondwana, which further split into the modern continents
what is PLATE TECTONIC THEORY?
the theory stating that Earth’s crust is made of several rigid plates moving relative to each other
what is a MID-OCEAN RIDGE?
a constructive plate boundary landform that is a system of submarine mountains and volcanoes
what is SUBDUCTION?
when the denser plate is forced under the lighter plate
what are FOLD MOUNTAINS?
parallel chains of high volcanic mountains formed from deformed sediments
what are ISLAND ARCS?
a line of volcanic islands
what is a HOT SPOT?
local heating at the boundary between the mantle and the core
what is VISCOSITY?
how liquid something is
what is an EFFUSIVE eruption?
one where the gases rise easily, so less pressure forms and eruptions are more gentle
what are EXPLOSIVE eruptions?
one where gases rise with difficulty, so pressure builds up causing more violent eruptions
what is TEPHRA?
solid material of varying grain size ejected into the atmosphere by the volcano
what are PYROCLASTIC FLOWS/NUEES ARDENTES?
gas-charged, hot, high speed flows of ash and tephra
what are LAHARS (volcanic mudflows)?
unconsolidated ash combined with water sweeping down a river valley
what is an EARTHQUAKE?
the release of pressure from a slow build up of stress within rocks
what is the FOCUS of an earthquake?
the point at which the pressure release occurs within the crust
what is the EPICENTRE of the earthquake?
the point immediately above the focus on the Earth’s surface
what is GROUND RUPTURE?
the visible breaking and displacement of the Earth’s surface
- this is a primary effect/hazard of a volcano
what is SEISMIC GAP?
an area that has not had any real seismic activity for 20 years
what is RETROFITTING?
making older structures more hazard resistant
what is the MOMENT MAGNITUDE SCALE (MMS)?
measurement of the size of the earthquake in terms of the energy released
what is the MERCALLI SCALE?
measurement of the intensity of the event and its impacts
what is a LANDSLIDE?
slope failure as a result of ground shaking
what is DRAWDOWN?
nthe wave trough in front of the tsunami causing a reduction is sea level
what is a WILDFIRE?
a large, uncontrolled inferno that burns and quickly spreads through wild landscapes
what is an IGNITION SOURCE?
the thing that starts a fire
what is FUEL?
something that feeds the wildfire
what are RETARDANTS?
chemicals that slow fires
what is PYROPHYTIC VEGETATION?
plants adapted to tolerate wildfires
what are CROWN FIRES?
wildfires that spread through the canopy
what are SURFACE FIRES?
fires that sweep rapidly along the ground
what is a TROPICAL STORM?
a low pressure revolving weather system that develops in the tropics
what is the CORIOLIS FORCE?
rotational force of the Earth
what is STORM SURGE?
a rapid rise in sea level where water is piled up against a coastline to a level in excess of a normal high tides
what is CONVECTION?
the movement caused by the tendency for hotter material to rise and cooler material sink
