Restless Earth Flashcards
What is the crust?
The outer layer of the earth
What is a plate?
A section of the earth’s crust
What is a plate margin?
The boundary where two plates meet
What is the mantle?
The dense, mostly solid layer between the outer core and the crust
What are convection currents?
The circular currents of heat in the mantle
What is subduction?
The sinking of oceanic crust at a destructive margin
What is a collision?
The meeting of two plates of continental crust. They are both the same type so they meet ‘head on’ and buckle
What is a fold mountain?
Large mountain range where rock layers have been crumpled is they have been forced together
What is an ocean trench?
A deep section of the ocean, usually where an oceanic plate is sinking below a continental plate
What is a composite volcano?
A steep-sided volcano that is made up of a variety of materials, such as lava and ash
What is a shield volcano?
A broad volcano that is mostly made up of lava
What is subsistence farming?
Farming to provide food and other resources for the farmer’s own family
What is irrigation?
Artificial watering of the land
What are terraces?
Steps cut into hillsides to create areas of flat land
What is hydroelectric power?
The use of flowing water to turn turbines to generate electricity
What are the primary effects of a volcano?
The immediate effects of the eruption, caused directly by it
What are the secondary effects of a volcano?
The after effects that occur as an indirect effect of the eruption on a longer timescale
What is aid?
Money, food, training and technology given by richer countries to poorer ones, either to help with an emergency or to encourage long-term development
What is a natural hazard?
An occurrence over which people have little control, which poses a threat to people’s lives and possessions
What is an earthquake?
A sudden and often violent shift in the rocks forming the earth’s crust, which is felt at the surface
What is an immediate response to a natural disaster?
How people react as the disaster happens and in the immediate aftermath
What are long term responses to natural disasters?
Later reactions that occur in the weeks, months and years after the event
What is the vent of a volcano?
The opening - usually central and single - in a volcano from which magma is emitted
What are lahar associated with a volcano?
These secondary effects of a volcanic eruption are mudflows resulting from ash mixing with melting ice or water
What is a super volcano?
A mega volcano that erupts at least 1000 cubic km of material
What is the caldera of a super volcano?
The depression of the super volcano marking the collapsed magma chamber
What is a fissure in the volcano?
An extended opening along a line of weakness in the volcano that allows magma to escape
What is the definition of geothermal?
Water that is heated beneath the ground, which comes to the surface in a variety of ways
What is a geyser?
A geothermal feature in which water erupts into the air under pressure
What is a hot spot?
A section of the earth’s crust where plumes of magma rise, weakening the crust. These are AWAY from plate boundaries
What is the focus of an earthquake?
The point on the earth’s crust where the earthquake originates
What is the Richter scale?
The logarithmic scale used for measuring earthquakes based on scientific recordings of the amount of movement
What is the epicentre of an earthquake?
The point at the earth’s surface directly above the focus
What are shock waves?
Seismic waves generated by an earthquake that pass through the earth’s crust
What is the Mercalli scale?
A means of measuring earthquakes by describing and comparing the damage done, on a scale from 1 to 12
Define ‘debt’
Money owed to others, to a bank or to aglow like organisation such as the World Bank
What are the three Ps?
Prediction, protection, preparation
What is prediction, in the context of earthquakes?
Attempts to forecast an earthquake - where and when it will happen - based on current knowledge
What is protection, in the context of earthquakes?
Constructing building so that they are safe to live in and will not collapse
What is preparation, in the context of earthquakes?
Organising activities and drills so that people know what to do in the event of an earthquake
What is a tsunami?
A special type of wave where the entire depth of the sea or ocean is set in motion by an event (usually an earthquake) which creates a huge wave
