Tectonic Key Definitions and Concepts Flashcards
A potential threat to human life and property
A hazard
The two causes of natural hazards
Hydro-meteorological (climatic processes) ans Geophysical (land processes)
Earthquakes not occurring at plate boundaries due to pre-existing weaknesses
Intra-plate earthquakes
Where do geophysical earthquakes occur?
Near plate boundaries
Localised areas of the lithosphere which has unusually high temperatures due to upwelling
Volcanic Hotspots
Name two examples of volcanic hotspots
Hawaii hotspot and The Ring of Fire
Where is the ring of fire located
Nazca , India-Australia and Pacific Plate
Inner core , outer core , mantle and crust
The layers of the earth
What are the two types of plates
Oceanic and Continental
A thick plate with land masses upon it
Continental plate
A thinner but denser plate with no land masses upon it
Oceanic plate
How do convection currents occur?
Radioactive reactions within the core
How do they plates move?
Convection Currents
The pulling force exerted by a cold, dense oceanic plate plunging into the mantle due to its own weight. The theory is that because the oceanic plate is denser than the hotter mantle beneath it, this contrast in density causes the plate to sink into the mantle.
Slab Pull theory
Name an example location of where slab pull theory is present
The Pacific Plate
Which theory states that the continents used to be connected in one large landmass known as a supercontinent but overtime the continents individually separated. Verified by the discovery of relating fossils on other sides of the ocean
Continental drift theory
Who theorised continental drift theory?
Wegner
What do the depth of seismic waves show?
It shows subduction of the denser basaltic oceanic plates in the upper mantle
When two oceanic plates move away from each other allowing magma from the mantle to move up and form new crust ridges within the ocean resulting in sea floor widening
Sea Floor Spreading
The record of geomagnetic data preserved in rocks and minerals
Paleomagntism
What are the three types of plate movements
Convergent , Divergent and Conservative
Volcanos , Earthquakes and Rift Valleys all from due to this plate movement
Constructive
Only Earthquakes occur here
Conservative
Volcanos , Earthquakes , Fold mountains , island arcs and ocean trenches all result from this plate movement
Destructive
Plates move away from each other
Constructive
Plates slide past each other
Conservative
Plates push against eachother
Destructive
What are the combinations of plates at a destructive plate margin?
continental + continental
oceanic + oceanic
continental + oceanic
What are the combinations of plates found at constructive plate margins?
oceanic + oceanic
continental + continental
Where does conservative margins occur?
Between any plates
the accumulation of material at the point of subduction
Accretion Wedge
Buildings designed to withstand seismic activity
Aseismic Buildings
The upper mantle layer of the earth , semi-molten and approx 2000km wide
Asthenosphere
This model shows that a hazard becomes a disaster if it affects a vulnerable population
Deggs Model
The point on the surface directly above the earthquakes orgin
Epicentre
The place at which the pressure/seismic energy is released
Focus
The sequence of governance of a natural hazard: monitoring , prediction , mitigation and preparedness
Hazard mitigation cycle
a sudden glacial flood caused by a glacier on top of or near a volcano melting due to the heat of the volcano
Jokulhaup
a flow of mud a debris
lahar
the upper crust of the mantle avg. thickness of 100km
lithosphere
a surface earthquake wave with horizontal displacement
Love waves or L waves
A measure of an earthquakes energy released considered the most accurate measurement
moment magnitude scale
a model describing the decline and recovery of a country over a period of time following a natural disaster
Parks Model
elements within the lithosphere have different melting points and so rock is partially melted and partially solid
Partial Melting
an earthquake waves causing compression within the body of the rock
P waves
a mixture of gases and rock fragments at high tempratures travelling at rapid speeds
pyroclastic flow
a surface earthquake causing both horizental and vertical displacement
R waves
a logarithmic measure of an earthquake’s intensity
Richter scale
an earthquake causing vertical displacement within the body of rock
S waves
the energy released in the form of P , L , S and R waves
seismic waves
initial vertical water displacement often from submarine earthquakes creates large waves with destructive power
Tsunami
a measure of a volcanos explosivity and eruption magnitude
volcanic explosivity index (VEI)
a region of the subducting plate most affected by pressure and friction where most destructive margin earthquakes occur
Wadati-Benioff zone
