Hazards key terms Flashcards
geophysical hazard
A natural event that may cause a loss of life and damage to building or land.
atmospheric hazard
potentially damaging natural event associated with changes in atmospheric conditions
hydrological hazards
extreme events associated with water occurrence, movement, and distribution
hazard perception
the way in which an individual or a group view the threat of a hazard event and this then influences their actions
fatalism
a view that suggests people cannot influence outcomes therefore nothing can be done to reduce (mitigate) the event or its impacts : an act of God ; people remain
prediction
the ability to give warnings so that action can be taken to reduce impacts - improved by monitoring, information sharing and communications technologies
adaptation
attempts by individuals and communities to live with hazard events and reduce their level of vulnerability
mitigation
actions taken to help reduce or eliminate long-term risks caused by hazards
resilience
the sustained ability to respond to, withstand and recover from the effects of natural hazards
preparedness
prearranged measures to reduce the loss of life and property damage through education, evacuation procedures, provision of emergency shelters and the taking out of insurance
hazard frequency
how often a hazard occurs - generally smaller
hazards occur more frequently, and larger hazards occur less frequently
hazard intensity
The measurement of the impacts of the hazard on a place ( e.g. Mercalli scale )
magnitude
an assessment of the size of an event (the amount of energy released)
hazard distribution
the pattern of where each hazard type is most likely to occur (and areas which don’t experience these)
level of development
is related to increase in economic output (wealth) coupled with improvement in social and political welfare of people within a country
Park’s model
(disaster-response curve)
a model graph to show the effects of a hazard on quality of life over a sequence of time and expected stages from pre-event to eventual recovery
hazard management cycle
the continuous process by which individuals and communities manage hazards in an effort to avoid or mitigate the impacts resulting from the hazards and learn to manage and prepare for them better over time
plate tectonic theory
the theory that Earth’s outer layer is divided into several plates that move over the mantle; the rocky inner layer above the core
crustal evolution
the rate of continental crustal growth and recycling through time and how changes in tectonic movement have influenced the rates of crustal growth and preservation
tectonic plates
the large, separately moving areas of the lithosphere that are the result of its breaking apart into seven or eight major sections (depending on how they are defined) and many minor ones
gravitational sliding
the movement downward or downslope of rock / lava in response to gravitational instability along particular slopes in unstable regions such as mid-oceanic ridges
ridge push
a proposed driving force for plate motion that occurs at mid-ocean ridges as the result of the rigid lithosphere sliding down the hot, raised asthenosphere underneath mid-ocean ridges - this push is caused by gravitational force and it exists because the ridge occurs at a higher elevation than the rest of the ocean floor
slab pull
the portion of motion of a tectonic plate that can be accounted for by its subduction and it is partly driven by the weight of cold, dense plates sinking into the mantle at oceanic trenches - the cooler sinking plate pulls the rest of the warmer plate along behind it
convection currents
heat from the earth’s core is transferred to the mantle. Rock, close to the core, is heated and so has plasticity and so it rises. When it reaches the crust it is forced sideways as often it cannot pass through the crust. The frictional drag between the convection current and the lower surface of the crust causes the tectonic plate to move. The more liquid rock then sinks back towards the core as it cools. The process then repeats.
sea-floor spreading
the formation of fresh areas of oceanic crust which occurs through the upwelling of magma at mid-ocean ridges and its subsequent outward movement on either side
constructive plate margin
sometimes called a divergent plate margin, occurs when plates move apart and magma wells up to fill the gap forming volcanic activity and new crust
destructive plate margin
sometimes called a convergent or tensional plate margin and this occurs when oceanic and continental plates move together leading to folding or subduction
conservative plate margin
sometimes called transform faults and these occur when plates slide past each other in opposite directions, but without creating or destroying lithosphere
young fold mountains
mountains that form mainly by the effects of folding on layers within the upper part of the Earth’s crust eg the Himalayas - at convergent margins
rift valleys
a steep-sided valley formed by the downward displacement of a block of the earth’s surface between nearly parallel faults or fault systems
ocean ridges
an elevated region with a central valley on an ocean floor at the boundary between two diverging tectonic plates where new crust forms from upwelling magma.
island arcs
volcanic islands that form parallel to ocean trenches in subduction zones
Magma plumes
is an upwelling of abnormally hot rock within the Earth’s mantle which can partly melt when they reach shallow depths near the surface and so are thought to be the cause of volcanic centers and hotspots
Lava flow
Mass movement on the surface of land of flowing lava
Pyroclastic flows
Tephra and hot gases mixed to create a mixture that flows down a volcano
Tephra
A solid matter ejected by volcanoes
Lahars
Hot mud flows when ash mix’s with water
Acid rain
Rainfall that has chemical within it
Seismic
Activity related to the earth plates
Liquefaction
The decomposition of soil with high water content to bring the water to rise
Tsunamis
A giant sea wave created by a large displacement of water
Land slide
Mass movement of land downhill
Shockwaves
Energy waves produced by an earthquake
Storm surges
Large sea waves that occur after a tropical storm due to higher sea levels
SaffirSimpson scale
The scale used to measure tropical storm magnitude
Retrofitting
Making older building out of new material to be stronger and more resistant
Ignition source
a natural or human source of a wildfire being set alight eg lightening or agricultural fires becoming out of control
Pyrophitic vegetation
plants adapted to tolerate fire through methods such as thick bark, tissue with high moisture content, seeds set by fire and underground nutrition storage
Retardants
chemicals sprayed on wildfires in order to slow them down and made from nitrates, ammonia, phosphates, sulphates and thickening agents
Multi-hazardous environment
a place with more than one hazard type happening over time - meaning there are interrelations between these hazards, including their simultaneous (at the same time) or cumulative (one after the other) occurrence and also their potential interactions eg storms + volcanic activity = lahars
