Flashcards
Tectonics Keywords
Cards in this deck (60)
- 1Natural Hazardnaturally occurring process or even that has the potential to affect people
- 2Natural disastermajor natural hazard - causes significant social, environmental and economic damage
- 3seismic hazardsgenerated when rocks within 700km of the Earths surface comes under stress - break + become displaced
- 4asthenosphereupper layer of the earths mantle
- 5lithospheresurface layer of Earth - rigid, outer shell
consists of crust and upper mantle - 6oceanic crustthin dense layer, (6-10km thin)
lines the ocean floor - 7continental crustolder thicker layer (45-50km thick)
makes up Earths landmasses
- less dense than oceanic crust - 8mantle plumevolcanoes form in middle of plates
plumes of magma rise upward + erupt onto the sea floor (hotspot) - 9paleomagnetismstudy of past changes of Earths magnetic field
(determined from rocks, sediment, archaeological records) - 10convectionheat produced by decay of radioactive elements from core
heats lower mantle = convection currents
rise because less dense
- falls because it cool + more dense
- thought to move in circles in the asthenosphere - causing plates to move - 11slab pullnewly formed oceanic crust at mid oceanic ridges = denser, thicker as it cools
causes it to sink into the mantle under its own weight = pulling the rest of the plate further
= forming deep ocean trenches - 12convergent boundarywhere 2 plates collide = destructive margin
- 13divergent boundary2 plates move apart = constructive margins
- 14conservative boundary= 2 plates slide past each other = transform margins
- 15locked faultnot slipping because of frictional resistance on the fault =
greater than the sheer stress across the fault
= its stuck - 16fold mountains2 continental plates collide = plates are folded and pushed up = chains of fold mountains
- 17sea floor spreadinghot magma is forced up from the asthenosphere + hardens
= new oceanic crust
- new crust pushes the tectonic plates apart = sea floor spreading - 18island arcsvolcanoes created as a result of subducted plates
volcanoes rise above sea level = seperate island volcanoes = found in curved lines - 19subduction2 oceanic plates or oceanic+continental - move towards each other - the less dense plate slides underneath the other, in the mantle.
where it melts = subduction zone - 20intensitymeasure of ground shaking
= building damage + collapse - 21magnituderelated to the amount of movement/displacement in the fault =
measure of energy release - 22benioff zonefriction between colliding plates (+subduction)
= intermediate + deep earthquakes
= benioff zone - 23primary waves (P Waves)fastest and first to reach the surface
- travel through both solid+liquid - 24secondary waves (S waves)slower
travel only through solids - 25surface love waves ( L waves)slowest but cause the most damage - shaking the ground from side to side
- larger + focus all their energy on Earths surface - 26seismic wavesshock waves released by tectonic movement + measured using a seismometer)
- 27Moment Magnitude Scale (MMS)measure magnitude ( energy released at epicentre)
- measures total energy released by an earthquake, at the moment it occurs - 28epicentrelocation on the Earths surface that is directly above the earths focus
- 29intra-plate earthquakesoccur in the middle of tectonic plates
- much rarer than boundary quakes - 30primary +secondary effectsprimary = direct result of hazard
secondary = indirect result of a hazard - 31crustal fracturingenergy released during an earthquake causes the Earths crust to crack
- 32soil liquefactionsecondary hazard
process by which water-saturated material can temp. lose strength + behave like a liquid under pressure of strong shaking
- occurs in saturated soils - 33landslides + avalancessecondary hazard
ground shaking places stress on slopes = landslides, rock slides, mudslides + avalanches - 34tsunamisecondary hazard
series of larger than normal waves
caused by volcanic eruption/underwater earthquakes - 35water displacementenergy released during an earthquake = seafloor lift
displacing the water column above
= tsunami wave - 36water columnarea of seawater from the surface to sea floor
- 37gas eruptionsmagma has dissolved gases
- released into atmosphere during volcanic eruption - 38pyroclastic flowsmixture of dense hot rock, lave, ash + gas ejected from a volcano
- 39tephra + ash fallpieces of volcanic rock + ash - blast into the air during volcanic eruptions
- 40laharssecondary hazard
masses of rock, mud + water
-travels quickly down volcano sides - 41Jokulhlaupssecondary hazard
heat of volcanic eruption - melts snow+ice in glaciers
= heavy/sudden floors - 42resiliencethe ability to protect lives+infrastructure from destruction
+ restore area after natural hazard occrus - 43riskexposure of people to hazardous event
- probability of a hazard occurring that leads to lives lost etc - 44vulnerabilitythe ability to anticipate, to cope with, resist and recover from natural hazard
- 45developmentlinked to +improving society - helps people achieve aspirations
provisions of social services, economic assets, improved productivity + reducing vulnerability
low levels of development = high risk levels + vulnerability to natural disasters - 46inequalityunfair situation or distribution of assets +resources
- 47governanceway individuals, institutions, public or private manage their common affairs
- 48Mercallimeasures earthquake intensity - takes observations from people who experienced the earthquake to hardly noticing it
- 49Tectonic Hazard Profiletechnique used to try understand the physical characteristics of different hazard types
- 50Hazard mitigationstrategies used to try avoid, delay or prevent hazard events
- land use zoning, diverting lava flow, GIS mapping, hazard resistant design +engineering - 51multiple hazard zonesarea at risk from many hazards
+ vulnerable - 52Hazard Adaptationstrategies used to reduce the impact of hazard events -
high tech monitoring, public education + community prepardness - 53land use zoninglocal government regulate how land in a community may be used
- 54hydro- meterologicalnatural hazards caused by climate processes -
droughts, floods, hurricanes, storms - 55PAR Modellooks at underlying causes of disaster
- looking at processes which create vulnerability (root causes, dynamic pressures + unsafe conditions) + the hazard itself - 56precursorswarning signs that suggest that a hazard may erupt
- 57hazard management cyclegoverments + other organisations - work to protect people
- different stages: response, recovery, mitigation, preparedness - 58Park ModelPark hazard- response curve is a mdoel that shows how a country may respond after a hazard event
- 59Early Warning Systemsin place in both Pacific +Indian Oceans
- use seismic sensors to detect underwater earthquakes - 60Hazard Risk EquationsR = Hazard x Vulnerability /
Capacity to Cope
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- A level Geography (TECTONICS) Flashcards on Tectonics Keywords, created by Amna Jamil on 23/05/2017.
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- Amna Jamil
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