Theme 3 - Tectonics Flashcards
what plate boundery is this? //
conservative
what plate boundery is this —–> <——-
Colision
what plate boundery is this? —> —
<–
destructive
what plate boundery is this? <—— ——–>
constructive
what is the convection current theroy?
plates move due to heat in the mantle rising creating convection currents. It cools at it reaches the top of the mantle then sinks
what is the theroy of slab pull?
plates move because gravity pulls them apart
what is an example of a constructive plate boundary?
the mid atlantic ridge
what is an example of a conservative plate boundary?
san andreas fault in california
what is an example of a destructive plate boundary?
the pacific ring of fire
what is an example of a colision plate boundary?
mount everist
what is a rift valley?
a steep sided valley formed by the pulling apart of the earths crust during plate movement. The land at the centre gradually colapses
what features are produced in a constructive plate boundarys?
rift valleys
shield volcanos
what features are produced on a conservative plate boundary?
earthquakes
what features are produced in a destructive plate boundary?
strato volcanos
earthquakes
ocean trenches
what features are produced in a collision plate boundary
fold mountains
earthquakes
what are ocean trenches?
long, deep gorges in the sea bed that occur around the edges of some oceans including the pacific ocean. they are formed by plate movements
what is a volcanic hotspot?
a point in the earths crust which has an unusually high amount of volcanic activity, some are on plate boundarys but others are in the middle of tectonic plates
what is magmas viscosity??
viscosity is a substance resistance to flow, for example maple syrup is more viscous then water ( it flows more slowly when you pour it)
what are the features of a strato volcano?
magma chamber
steepsides
crater
layers of ash and gas
main vent
secondary vents
what are the features of a shield volcano?
magma chamber
wide base
crater
broad peak
gentle slopes
how does a caldera form?
in some volent eruptions so much lava and agas is ejected that the magma chamber that supplies the volcano empties. The upper part of the volcanos collapses into empty space bellow creating a circular depression which is larger than a typical volcano vent
what are cinder cones?
are the smallest and most common type of volcano which have steep sides. They are biult from particles and blobs of lava that cools quikcly when thrown into the area that fall around the vent to form a cone shape. They have voilnet explosive eruptions and are ofton found in one singular eruption
how does a geyser form?
Water interacts with heat in the ground to form geysers
When rainwater or snow-melt percolates downwards and meets hot rocks
The water is heated which causes it to expand
This increases the pressure and forces a mixture of boiling water and steam back up through fissures in the ground
Then it explodes, releasing steam into the air
what are lava tubes?
lava tubes are empty tunnels that form when liquid lava drains away
how do lava tubes form?
Lava flows from volcanic eruptions, the eruptions tend to become channeled into a few main streams. The overflow of lava from the streams often cools and solidifies creating stacked layers of lava around the flow. After many hours or days the lava melts downward into the ground giving the tube a taller more narrow cross-section. A solid crust can form overhead and enclose the tube. The tube then insulates the flowing lava within, allowing it to flow great distances. After the eruption subsides and the flows harden these lava tubes become a cave.
what is an epicenter of an earthquake?
the point of the earths surface directly above the surface - usually the place of most damage
what is the focus of an earthquake?
the exact point bellow th earths surface when the plates slip
what are the factors affecting the damage caused by earthquakes
size of the earthquake
quality of emergency services
building design and construction
time of day
education
physical landscape
why was the Haiti earthquake such a disaster
its an lic, 60 percent of the population live below the poverty line
over half of Haitians are undernourished, limited access to basic resources
poorly constructed buildings/ no building costs
weak political governance
why was the Haiti earthquake such a disaster
its an lic, 60 percent of the population live below the poverty line
over half of Haitians are undernourished, limited access to basic resources
poorly constructed buildings/ no building costs
weak political governance
what were the social impacts of the Haiti earthquake
over 220,000 people killed, 300,000 injured and 1.3 million people made homeless - around 3 million affected
the large number of deaths meant that hospitals and morgues became full and bodies then had piled on the streets
large number of bodies meant diseases especially cholera killed at least 7,000 people because there was not enough water sanitation
people were squashed into shanty towns - leading to poor sanitation health and a big looting problem
what were the economic impacts of the Haiti earthquake
1 in 5 people lost there jobs because so many buildings where destroyed - largest industry clothing was badly affected
total damage was 11.5 billion dollars
what were the environmental impacts of the Haiti earthquake
homes destroyed or badly damaged
transport and communication links damage
hospitals and schools were badly damaged
the prison was destroyed and 4,000 inmates escaped
difficulties getting aid to Haiti because of the airport control tower that was destroyed and bad management
what is a tsunami
a huge wave or series of waves usually caused by an earthquake on the ocean floor
what type of plate boundary are tsunamis formed on
destructive plate margin
what are tsunamis caused by
violent movements of the ocean floor such as those during an earthquake this movement displaces huge amounts of water upwards which creates a series of waves
what are the signs of a tsunami
water draws back suddenly into the sea
birds fly and squeak out
what are the social (health) impacts of the boxing day tsunami
in Bandsarlteeh 1,500 settlements wiped out
foreign visitors dropped dropped by 80 percent in 2005
220,000 people died
650000 were seriously injured
2 million displaced
threat of disease
what are the infracturial impacts of the boxing day tsunami
dozend of buildings destroyed in intial earthquale in indonisia
public buildings where wiped out
what are the economic impacts of the boxing day tsunami
60 percent of fishing industry was destroyed
foreign visitors dropped by 80 percent in 2005
what is a lahar
a fast moving mud flow
what causes a lahar
when ice or snow on the side of volcano melts and mixes with the soil and rocks
what are the health impacts of the mount st helens eruption
57 people died from eruption almost instantly, from a cloud of hot ash and dust that came down the mountain
massive areas of crops and forest are wiped out - damage to crops is estimated at 175 million dollars
what are the infrastructural impacts of the st helen eruption
mudflows 200m thick flow down the mointain causing rivers to be blocked - took the
what are the economic impacts of the st helen eruption
the number of tourists visiting the area increased to view the devastation and recovery of the landscape, plants and animals
