Hazards: Key Words Tests Flashcards
Acid dome volcanoes
Steep-sided convex cones associated with viscous, silica-rich gaseous lava that solidifies before running too far down slope.
Adaptation
Accepting that natural events are inevitable and adapting our behaviour accordingly.
Asthenosphere
A layer of softer almost-plastic like rock which moved very slowly and carries the lithosphere on top.
Atmospheric hazards
Hazards driven by processes at work in the atmosphere.
Caldera
Vast pit crater formed by a violent eruption which blows off the volcano’s summit.
Composite cones (strato-volcanoes)
Formed from alternating eruptions of ash, tephra and lava, which builds up the volcano in layer, producing weaknesses that can be exploited by the magma.
Conservative plate margins
When two plates slide past each other and crust is not destroyed by subduction.
Constructive (divergent) plate margins
When two plates separate or diverge.
Core
The centre and hottest part of the Earth, made up of the outer core and inner core.
Crown fire
Wildfire which spreads across tree canopy and affects forested areas.
Crust
The Earth’s outer shell, made up of oceanic crust and continental crust.
Destructive (convergent) plate margins
When two plates collide or converge.
El Niño
A cyclical climatic condition which involves the warming of the Pacific off the west coast of South America and affects global patterns of temperature and rainfall.
Extrusive
Lava that is in contact with the air or sea, resulting in igneous rock which tends to be fine-grained with small crystals.
Eye wall
The bank of cloud which rings the central eye in a tropical storm.
Fatalism
An acceptance that hazards are natural events that we can do little to control and losses have to be accepted.
Fissure eruptions
When lava escapes through a split or crack in the rock, which can create extensive lava plateaus.
Geophysical hazards
Hazards driven by the Earth’s own internal energy sources.
Gravitational sliding
The movement of tectonic plates as a result of gravity.
Ground fire
Wildfire which burns beneath the ground layers of dry organic peat.
Hazard
The threat of substantial loss of life, substantial impact upon life or damage to property that can be caused by an event.
Hazard management cycle
A theoretical model of hazard management as a continuous 4-stage cycle involving mitigation, preparation, response and recovery.
Hot spot
An area where radioactive decay within the Earth’s core is concentrated, generating very hot temperatures and heating the lower mantle.
Hydrological hazards
Hazards driven by water bodies (mainly the oceans).
Igneous rocks
Rocks formed by the cooling of molten magma, either underground (intrusive) or on the ground surface (extrusive).
Indian Ocean Dipole (IOD)
A cyclical ocean and atmospheric phenomenon that affects the climate of countries that surround the Indian Ocean Basin.
Intrusive
Magma that cools, crystallises and solidified slowly below the surface resulting in coarse-grained igneous rocks.
Ladder effect
The process of fires from the forest floor spreading to the tree canopy.
Lahar
Mudflow composed mainly of volcanic ash mixed with water from a crater lake, snowmelt, glacier melt or prolonged torrential rain.
Liquefaction
The jelly-like state of silts and clays resulting from intense ground shaking.
Lithosphere
The outermost solid layer of the Earth, approximately 100km thick, comprising the crust and upper mantle.
Love (L) waves
Seismic waves which travel on the surface and are the slowest waves but cause the most damage.
Magma
Molten rock, gases and liquids from the mantle accumulating in cast chambers at great pressure deep within the lithosphere.
Magma plume
A rising column of hot rock created by hot spots heating the lower mantle, creating localised thermal currents.
