Tectonic Processes and Hazards: Key Words Flashcards
Section A, Unit 1
Resilience
The ability to protect live, livelihoods and infrastructure from destruction, and to restore an area after a natural hazard has occurred.
Risk
The exposure of people to a hazardous event; it is the probability of a hazard occurring that leads to the loss of lives and/or livelihoods.
Development
Linked to improving society, enabling people to achieve their aspirations. It includes the provision of social services, acquisition of economic assets, improved productivity and reducing vulnerability to natural disasters.
Inequality
An unfair situation or distribution of assets and resources. It may be seen when people or nations and non-state players have different levels of authority, competence and outcomes.
Governance
The sum of many ways individual, institutions, public and private manage their common affairs. It is a continuing process through which conflicting or diverse interests may be accommodated and co-operative action may be taken.
Intra-plate
Relating to or occurring within the interior of a tectonic plate.
Hot Spots
An intra-plate location, oceanic or continental, where magma from the mantle has broken through a weak point in the crust.
Mantle Plumes
Hotter areas of the mantle that move upwards underneath the crust and push it up. They can cause weak points in the crust which can become hotspots. The two main mantle plumes are the Pacific and African.
Paleomagnetism
When magmas and lavas solidify, the iron minerals in the rock align with the earth’s magnetic field, permanently recording the direction.
Asthenosphere
The upper layer of the Earth’s mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.
Lithosphere
The lithosphere is the solid, outer part of Earth - it includes the outermost layers of Earth’s surface; the brittle upper portion of the mantle and the crust.
Convergent Boundary
Where two plates move towards each other and at the boundary the denser oceanic plate (basaltic) is subjected beneath the less dense continental plate (granitic).
Divergent Boundary
Where two plates move apart from each other.
Transform Boundary
Where two plates slide past each other, either moving at different speeds or in different directions.
Locked Fault
A fault that is stuck because of frictional resistance on the fault is greater than the sheer stress across the fault.
Fold Mountains
As two continental plates collide, the plates are folded and slowly push up, forming chains of fold mountains (e.g. Himalayas)
Orogeny
A process in which a section of the earth’s crust is folded and deformed by lateral compression to form a mountain range.
Sea Floor Spreading
These are formed when hot magma is forced up from the asthenosphere and hardens - forming new oceanic crust that pushes the tectonic plates apart.
Island arcs
Volcanoes created as a result of subjected plates. These volcanoes rise above sea level to form separate island volcanoes, which are usually found in a curved line.
Subduction
As two oceanic plates or an oceanic and a continental plate move towards each other, one slides under the other into the mantle - where it melts in an area known as the subduction zone.
Intensity
A measure of the ground shaking. It is the ground shaking that causes building damage and collapse, and all the loss of life from the hazard.
Magnitude
The magnitude of an earthquake is related to the amount of movement, or displacement, in the fault , which is in turn a measure of energy release.
Benioff Zone
The area in which the friction created between colliding plates (and subduction) causes intermediate and deep earthquakes.
Primary waves
The fastest and hence the first to reach the surface as they travel through both solids and liquids.
Secondary Waves
These are slower than P waves, as they only travel through solids.
Rayleigh Waves
Only travel through the surface of the crust, in a rolling motion. The ground is moved up and down and side to side. It is responsible for most of the shaking felt by people.
