Glossary: Restless Earth Flashcards
Collision boundary/ margin
Where two plates are moving together (destructive) and upward, creating mountains.
Conservative boundary/ margin
Where two plates pass alongside each other.
Constructive boundary/ margin
Where two plates move apart.
Continental drift
The theory that describes how plates have moved over millions of years.
Convention current
Movement of magma within the Earth’s mantle, formed by radioactive decay creating heat.
Crust
The outermost layer of the Earth.
Earthquake
A sudden and violent shaking of the Earth’s crust.
Fold mountains
Mountains formed by plate collision, crumpling rock layers.
Hot spot
Where magma plumes rise away from plate boundaries, breaking through the crust.
Magma
Molten rock within the Earth’s mantle.
Outer core
An inner section of the Earth - liquid comprising mostly of iron, at 10-12 g/cm cubed.
(Tectonic) Plate
A huge section of the Earth’s crust.
Plate boundary/ margin
Where any two plates meet.
Plate tectonics
The theory of the distribution of earthquakes, volcanoes, fold mountains and plate movement.
Richter scale
Measures the strength/magnitude of an earthquake - 0 to 10.
Subduction
The sinking movement of one plate beneath another at a destructive margin.
Tectonic activity
Changes taking place in the structure of the Earth.
Tsunami
A wave, often generated by an earthquake, which displaces water and causes devastation.
Vent
The opening of a volcano.
Volcano
Cone-shaped mountain created by lava from repeated eruptions.
Basic lava
Thin ‘runny’ lava, low silica content, flows long distances.
Caldera
The depression of a supervolcano, marking the collapsed magma chamber
Composite volcano
Steep-sided cone with successive layers of ash and lava
Epicentre
The point at the Earth’s surface directly above the focus of an earthquake
Fissure
Extended opening along a line of weakness, allow magma to escape to the surface
Focus
The point where an earthquake originates
Geyser
A geothermal feature in which water erupts into the air under pressure
Geothermal
Water that is heated beneath the ground, which comes to the surface in a variety of ways
Hazard
An event where lives and property are threatened, resulting in damage and/ or death
Immediate responses
How people react as the disaster happens and in the immediate aftermath
Lahar
Secondary effect of a volcano where mudflows form from the mixing of ash and melted ice/ water
Lava
Name for magma once at the Earth’s surface
Long term responses
Later reactions that occur in the weeks, months and years after the event
Mantle
The dense, mostly solid layer between the outer core and the crust
Mercalli scale
Measures the destructive power of an earthquake - I to XII
Ocean trenches
Deep sections of ocean where an oceanic plate subducts below a continental plate
Prediction
Attempts to forecast an even - where and when it will happen - based in current knowledge
Protection
Constructing buildings so that they are safe to live in and will no collapse
Preparation
Organising activities and drills so that people know what to do in an earthquake
Shield volcano
Gentle sides, wide base made of basic lava
Shock waves
Seismic waves generated by an earthquake that pass through the earth’s crust
Supervolcano
A colossal volcano that erupts at least 1,000 km cubed of material
