Global Hazards key words

Aftershocks

Smaller earthquakes and tremors that occur after the main earthquake.

Collision Plate Boundary

Two plates moving towards each other forming fold mountains.

Conservative Plate Boundary

Two plates are moving alongside each other either past each other or in the same direction but a different speeds

Constructive plate boundary

Two plates moving away from each other causing magma to rise from the mantle creating a new crust

Continental crust

Thick, not very dense crust that carries land

Convection currents

Radioactive decay in the earths core that causes hot circular convection currents to rise and causing the movement of tectonic plates

Destructive plate boundary

Two plates moving towards each other often creating a subduction zone where an oceanic plate is pushed under a continental plate

Drought

A prolonged period of abnormally low rainfall

Earthquakes

The shaking and vibrations of the earths crust due to the movement of tectonic plates caused by the release of built-up pressure inside the earths crust

El Niño

A warm ocean current that flows along the coast of Peru (South America)every 7 to 14 years that disrupt climate patterns bringing drought to Australia and India and flooding to Peru

Epicentre

The point of the Earth surface directly above the focus of an earthquake

Extreme weather

This is when a weather event is significantly different from the average or usual weather pattern or a Weather event that can cause risk to life/damage to property

Focus

The point inside the crust where the pressure builds up the most

Global atmospheric circulation

The global pattern of winds and air pressure the includes the Hadley, feral, and polar cells

Hadley cell

A convection current in the atmosphere, the cycles between the equator and 30° N and 30°S

Heat wave

Prolonged Period of abnormally hot weather

Lahar

Mad flow mixed with water, lava, ash, and dust

Magma

Molten rock

Mitigation

Reducing the negative impact e.g. hazard mitigation means reducing the negative impacts of hazards

Oceanic crust

Thinner, dense crust that carries ocean

Plate margin/boundary

The area where tectonic plates meet

Primary impacts

Immediate effects that happen during or just after the event

Pyroclastic flow

Mixture of hot steam, lava, ash and dust travelling at huge speeds

Richter scale

A scale that measures the magnitude of an earthquake (1-10)

Secondary impacts

Affects that take place a while after the event has taken place

Seismometer/Seismograph

An instrument that measures the impact of an earthquake by measuring the amount of energy it generates

Subduction zone

Where the less dense oceanic plate is forced under the more dense continental plate

Tectonic plates

Parts of the earths crust broken into several pieces that are in constant motion.

Tropical storm

A strong storm near the equator with winds moving in a circle that feeds on the energy from a warm ocean

Tsunami

A huge wave usually caused by volcanic or earthquake activity under the sea

Volcanoes

Cone shaped hills or mountains formed by a eruptions of lava and ash. Can occur at constructive and destructive plate boundaries.