Tectonic Hazards Keywords Flashcards
(23 cards)
collision margin
Two continental plates of the same density move towards each other. No subduction occurs, instead they squeeze upwards making fold mountains.
conservative margin
Tectonic plates slowly sliding past each other. The plates may become stuck, causing a build-up of pressure. When the plates snap past each other, the friction can cause earthquakes - but not volcanoes.
constructive margin
Two tectonic plates moving apart, magma can rise up in the gap as volcanoes. As the plates pull apart, the friction may cause small earthquakes.
continental crust
Older and thicker crust which is mainly composed of granite
convection currents
In the Earth’s mantle the currents which rise from the Earth’s core. They are strong enough to move tectonic plates.
core
The central part of Earth and it is made of two sections - the solid inner core and the semi-liquid outer core
crust
The outer layer of the Earth which is sub-divided into tectonic plates.
destructive margin
When oceanic plate is moving towards a continental plate, the oceanic plate subducts under the continental plate and melts to make magma. Volcanoes, earthquakes and fold mountains are found along a destructive margin.
earthquake
When tectonic plates snap past each other, energy is released causing an earthquake.
epicentre
The point on the ground directly above the focus of an earthquake.
fault
A fractured surface in the Earth’s crust.
focus
The point of origin of an earthquake.
fold mountain
A mountain range formed by the collision of a continental plate with either another continental plate or an oceanic plate.
magma
Melted rock below the Earth’s surface. When it reaches the surface it is called lava.
mantle
The middle layer of the Earth, between the crust and the core. It consists of magma.
oceanic crust
The younger and thinner crust. Oceanic crust is denser and is subducted at destructive plate margins.
richter scale
The method of measuring how strong an earthquake is.
seismograph
A measuring instrument designed to record the intensity and duration of earthquakes.
subduction
The transformation into magma of a denser oceanic plate as it sinks under a less dense plate.
tectonic plate
The large pieces of broken crust that cover the Earth.
tsunami
Huge wave caused by an earthquake under the sea.
vent
In a volcano, a gap which allows lava to erupt onto the surface of the Earth.
volcano
Created when magma rises and is forced out through the crust in eruptions.
