1. Restless Earth Flashcards
The size of an earthquake measured using a logarithmic scale
Magnitude
Convection currents
Circulating movements of the magma in the mantle cause by the heat if he core (radioactive decay)
Part of the crust made from dense basaltic rocks
Oceanic crust
Part of the crust made from less dense rock e.g. Granite
Continental crust
Primary impacts/effects
Immediate effects/impacts that are caused directly by an event e.g. Earthquake (buildings collapse)
The after effects of an event e.g fires due to gas leaks due to cracked gas pipes
Secondary impacts/effects
Describe the structure of the Earth including the state (solid or liquid) of each section
Inner core (solid)
Outer core (liquid)
Mantle (molten rock)
Crust (solid)
Define lithosphere
The surface of the Earth (the crust)
Define asthenosphere
The top layer of the mantle
Define Pangea
When all the continents were joined together
Define plate boundary
Where two or more plates meet together
Constructive plate boundary e.g Eurasian and North American plates
Two oceanic plates moving apart. New oceanic crust constantly formed in the gap created. Magma injected between the plates, it cools and forms new crust. Magma is runny- forms shallow sided volcanoes. Earthquakes caused by friction as the plates move apart.
Oceanic plate meets continental plate (moving towards each other). Denser plate (oceanic) is subducted. As it sinks it melts and makes magma called andesite. Sinking plate sticks to continental, pressure builds and friction causes earthquakes.
Destructive plate boundary e.g. Nazca and South American plate
Plates slide past each other and friction causes earthquakes. Plates can move in the same direction or opposite. No volcanoes.
Conservative plate boundary e.g. North American and Pacific plate
Collision plate boundary e.g. Indian and Eurasian plates
Two continental plates moving towards each other. Plates are not sense enough to sink into the mantle so they buckle and form fold mountains. Powerful earthquakes but no volcanoes.
