2.1 Earthquakes And Volcanoes Flashcards
Crater
Depression at the top of a volcano following a volcanic eruption. It may contain a lake
Lava
Molten magma that has reached the earths surface.
May be liquid or may have solidified
Shield volcano
Gently sloping volcano produced by very hot runny lava
Cone volcano
Steeply sloping volcano produced by thick lava
Ash
Very fine grained volcanic material
Cinders
Small sized rocks and coarse volcanic materials
Magma
Molten rock within the earth
Magma chamber
Reservoir of magma located deep inside volcano
Pyroclastic flow
Super hot (700 Celsius) flows of ash, pumice (volcanic rocks) and steam at speeds of over 500 km/h
Vent
Channel through which volcanic material is ejected
Dormant
Volcanoes which have not erupted for a very long time but could erupt again
Active
A volcano currently showing signs of activity
Extinct
A volcano which has shown no signs of activity in historic times
Intensity
Power of an earthquake is generally measured using Richter scale or sometimes the Mercalli scale
Richter Scale
Open ended scale to record magnitude of earthquakes - the higher the number or the scale, the greater the strength of the earthquakes
More small EQ than larger
Mercalli scale
Probably not needed
Relates to ground movement to commonplace observations of ie light bulbs, book cases and building damage
Epicentre
Point on the earths surface directly above focus of an earthquake
Strength of the shock waves generally decrease away from the epicentre
Focus
Position within earth where an earthquake occurs,
Earthquakes may be divided into shallow focus and deep focus earthquakes depending on how far below the earths surface they occur
Describe difference between composite volcanoes and shield volcanoes
7 major tectonic plates
Eurasian North American South American African Indo-Australian Pacific Antarctic
Minor plates
Tectonic
Caribbean Juan de Fuca Cocos Aegean Adriatic Turkish
World map of tectonic plates
Describe 4 processes at plate boundaries
Give causes of earthquakes and volcanoes
Nuclear testing
Weight of large dams
Drilling for oil / fracking
Earthquake primary, secondary hazards and impacts
Volcanoes direct, indirect hazards and socio-economic impacts
Opportunities provided by volcanoes
New land and islands for people to live
Fertile soils
Soils rich in minerals
Important as tourist destinations
Give main ways to deal with earthquakes
Reducing impact
Better forecasting and warning
Building location
Building design
Emergency procedured
Predicting earthquakes
Small-scale ground surface changes Ground tilt Changes in rock stress Micro-earthquake activity Changes in radon gas concentration Unusual animal behaviour, esp. toads
