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Cambridge IGCSE Geography- Earthquakes and Volcanoes
Terms in this set (35)
An opening in the Earth's crust through which hot molten magma, molten rock and ash are erupted onto the land.
Depression at the top of a volcano following a volcanic eruption.
Molten magma that has reached the Earth's surface is lava. Magma is molten materials underneath the surface of the Earth.
Gently sloping volcano produced by very hot, runny basaltic lava. Associated with constructive boundaries and hotspots.
Cone volcano (Composite, acid volcano or strato-volcanoes)
Steeply sloping volcano produced by thick, viscous, acidic lava, ash and cinders. Associated with destructive plate boundaries.
Formed by alternative layers of ash and lava due to alternative eruptions of these.
Very fine-grained volcanic material
Small-sized rocks and coarse volcanic materials
The reservoir of magma located deep inside the volcano.
Superhot (700 degrees) flows of ash, pumice and steam at speeds of over 500 km/h
The channel through which volcanic material is ejected.
Volcanoes which have not erupted for a very long time but could erupt again.
A volcano currently showing no signs of activity but has erupted in recent times.
A volcano which is never expected to erupt again.
Records magnitude of an earthquake. The intensity is multiplied by 10 as the number increases.
Relates grounds movement to commonplace observations
The point on the Earth's surface directly above the focus of an earthquake.
The position within the Earth where an earthquake occur. Earthquakes may be shallow-focus or deep-focus.
Sudden, violent shaking of the Earth's surface. Occur after a build-up of pressure causes rocks and other materials to give way.
Volcanic Explosive Index (VEI)
A measure of the strength of a volcano based on the amount of material ejected, the height of the cloud it causes and the amount of damage caused.
A volcano with with a VEI 8
A natural event that causes damage to property and/or disruption to normal life and may cause loss of life.
Also known as a seismic sea wave, is a series of waves in a water body caused by the displacement of a large volume of water, generally due to an earthquake.
Two plates move apart from each other causing sea-floor spreading, new oceanic crust is formed, creating mid-ocean ridges, volcanic activity is common.
Convergent/destructive boundary (subduction zone)
The oceanic crust moves towards the continental crust and sinks beneath it due to its greater density, deep-sea trenches and island arcs are formed, the continental crust is folded into fold mountains, volcanic activity is common.
Two continental crusts collide, as neither can sink they are folded up into fold mountains.
Two plates slip sideways past each other but land is neither is destroyed nor created.
An intra-plate volcano caused by a weakness in the earth's crust or particularly hot magma rising to the surface and breaking through the crust. Hawaii sits on and has been created by a hotspot.
A rift valley is a type of divergent plate boundary. As the plates pull apart the land in between the plates collapses creating a rift valley. Overtime this valley firsts fills up with lakes, magma is also able to escape.
This layer is believed to be solid, because of the immense pressure placed upon it. It is also extremely hot at about 5,500 degrees.
This layer is believed to be semi-molten and largely made of iron and nickel. It is extremely hot with temperatures up to 5,500 degrees.
This the thickest section of the earth with a diameter of about 2900km. The mantle is often described as being semi-molten. Convection currents are found in the mantle.
Solid: oceanic crust and continental crust. The depth varies between 10 and 70 km. Continental crust is mostly formed of granite and is less dense than the oceanic crust.
Major plate boundaries
Pacific, Indo-Australian, Antarctic, North American, South American, African and Eurasian plates.
Hot currents rise towards the Earth's surface, drag continents apart and cause them to collide. The Earth's surface moves around on the semi-molten magma.
THIS SET IS OFTEN IN FOLDERS WITH...
Cambridge IGCSE Geography 04 - Energy Resources
Cambridge IGCSE Geography 12 - Water Resources
Cambridge IGCSE Geography 08 - Plate Tectonics
Cambridge IGCSE Geography - Development
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