Key words Flashcards
What is the mantle?
The mantle is a solid, but because of the very high temperatures present it is deformable (plastic) and capable of very slow ‘flow’.
What are mantle plumes?
Mantle plumes are concentrated areas of heath convection. At plate boundaries they are sheet-like, whereas at hot spots they are column-like.
What is subduction?
Subduction is the process of one plate sinking beneath another at a convergent plate boundary.
What is the difference between the focus and the epicentre?
An earthquake originates at the focus.
The epicentre is the point on the Earth’s surface directly above the focus.
What are pyroclasts?
Pyroclasts (meaning ‘fire broken’) are any rock fragments ejected from a volcano including ash, tephra and volcanic bombs.
What is a threshold?
A threshold is the magnitude above which a disaster occurs. This threshold level could be different in a developed versus a developing country because of different levels of resilience.
What is resilience?
Resilience is the ability of a community to cope with a hazard; some communities are better prepared than others so a hazard is less likely to become a disaster.
What is a megadisaster?
A megadisaster is a disaster with unusually high impacts. Today that means millions of people affected and billions of dollars in damage over a wide area, i.e. an entire region or even more than one country.
What is a supervolcano?
A supervolcano is one whose impacts would be felt globally, because of a worldwide cooling of the Earth’s climate, perhaps for up to 5 years.
What is liquefaction?
Liquefaction occurs in waterlogged, loose sediment; earthquake shaking ‘liquefies’ the ground, causing buildings to tilt, sink and collapse.
What are aftershocks?
Aftershocks occur in the hours, days and months after a primary earthquake and can be of high magnitude; they often number in the hundreds or thousands.
What is corruption?
Corruption refers to illegal practices, such as accepting bribes designed to influence decision making or paying people to stay silent about known problems.
What is land-use zoning?
Land-use zoning is a planning too used to decide what type of buildings (residential, commercial, industrial or none) are allowed in particular locations.
What are multiple hazard zones?
Multiple hazard zones are places where two or more natural hazards occur, and in some cases can interact to produce complex disasters.
What is prediction?
Prediction means knowing when, and where, a natural hazard will strike on a spatial and temporal scale that can be acted on meaningfully in terms of evacuation.
