Tectonics Flashcards
symmetrical magnetic anomalies
the change in size of the earths magnetic field outside of the expectation
Magnitude
The size of something
Moment magnitude scale
The most accurate earthquake magnitude scale measures the total energy released by an earthquake
Destructive plate boundary
(Convergent boundary) where 2 plates with different density meet the oceanic plate subducts beneath the continental plate
Subduction
The denser plate sinking beneath the other
Intra-plate
Within the plate away from plate boundary
Hot spot
A stationary plume of magma beneath the crust where volcanoes can form from
Mantle plume
Hotter areas of the mantle that move upwards underneath the crust and push it up
Convection
Heat rising and falling in the mantle
Earthquake(seismic) waves
Shockwaves created by release of tension at a focal point
Slab pull
When the descending part of the ocean plate pulls the rest of the plate with it
Constructive plate boundary
Tectonic plates moving away from each other and magma rising up and cooling to create new rock (divergent)
Collision plate boundary
Where two plates move towards each other causing a very slow collision causing folding and faulting of crustal rocks
Transform plate boundary
Where two plates meet at a major fault in earths crust usually with movement in contrasting directions creating friction (conservative)
Benioff zone
The area where friction is created between colliding tectonic plates, resulting in intermediate and deep earthquakes
Sea floor spreading
Large slabs of earths lithosphere pull apart from each other (they split)
Frictional drag
Force on an object such as air as it moves across the earths surface
Focus
Place inside earths crust where the earthquake originates
Epicentre
Point on earths surface directly above the focus
Paleognetism
When magma solidifies the iron aligns with earths magnetic field recording the direction.
When studied it was found the rocks had recorded magnetic fields in opposite directions
Tsunami
A sequence of huge waves caused by a large displacement of water
Landslides
Mass movement of rock down a steep slope
Liquefaction
Groundwater and loose soil and sediment shaken so ground loses cohesion and acts like fluid
Mercalli intensity scale
Earthquake intensity scale based on 12 levels of damage to areas
Water column displacement
The movement of a large volume of water above the point the seabed was moved up or down
Intensity
The effect of an earthquake on earths surface
Run-up
Height of tsunami above sea level at the farthest point it reaches on the shore
Pyroclastic flows
Hot mix of rock fragments gas and ash that travel rapidly away from a volcanic vent
Lahars
Hot or cold mix of water and rock fragments that flow quickly down the slopes of a volcano
Jokulhaups
Glacial outburst floods from underneath an ice cap or glacier
Disaster
The effect of a hazard on society usually used when significant property damage loss of life or injuries
Natural hazards
Extreme natural events
Mega-disaster
High magnitude high impact infrequent disaster that affects several countries directly or indirectly
Socio economic impacts
The effects on people and businesses and employment of an event or process
Spatial predictability
The area a hazard event may occur with some certainty
Pressure and release model
Model of cause and effect summarising the pressures caused by natural hazards and how they could be reduced
hazard
something that has a negative impact on people in any way
speed of onset
how fast a natural hazard may occur
vulnerability
the weaknesses of people in a situation where they are exposed to risk
community adaptation
a community working together to change their way of life so that hazard events have less impact
preparedness
research based actions taken as precautionary measures for potential disaster
governance
how a place is managed by different levels of government
hazard profiles
analysis of different types of hazard based on range of criteria
multiple hazard zones
place that has several natural hazards
focal depth
depth to which an earthquake starts
disaster trends
what has been happening to the number of severe tectonic hazards over time
slow onset
hazard event that come on slowly with lots of indication
rapid onset
hazard event that comes on quickly with little warning
hydro-meteorological
hazards associated with flowing water or the weather
response curve
a graph showing the time taken to recover from a hazard
land use zoning
regulations to stop activities in an area prone to hazards that poses a risk
hazard resistant design
buildings made to withstand hazard events
modify the event
alter the hazard itself to reduce or change its impacts e.g changing where the lava flows to
modify vulnerability and resistance
making people less vulnerable - will help scale of disaster
modify loss
reduce impact of losses e.g insuring property
hazard management cycle
