28 terms

grade 8 eatrh forces and tropical rainforests

What are the 4 structures of the Earth?
crust, mantle, inner core and outer core.
what are the 3 types of plate margins?
A destructive margin, a consrtuctive margin and a conservitive margin.
What is a destructive margin?
A destructive margin is when two plates are pushing against each other and the heavier, denser oceanic crust burries itself underneath the lighter, less dense continental crust is pushed upwards and this can cause earthquakes and volcanic eruptions. Examples of this are Mt. St. Helens, Nevada del Ruiz and Mt. Unzen.
What is a constructive margin?
A constuctive margin is when the plates are pulled apart and this creates mountain ranges and volcanoes. Earthquakes and volcanic eruption can also occur from this natrual disaster.
What is a conservitive margin?
A conservitave margin is when two plates rub past each other and creat a large amount of friction and heat. An example of this is the San Andreas fault line.
What 2 scales are Earthquakes measured on?
An Earthquake is measured on intensity and damage. The intensity in measured on a Richter scale and the damage is measured on a Mercalli scale.
Whats the difference in amount of damage between a LEDC and a MEDC? Give reasons.
The amount of differnce in damage is quite big beacause in a LEDC there is usually more damage done because the buildings are not built as well and are not quite so sturdy and also after the earthquake has been, they don't have as much money to clear up the death and destruction. Whereas in a MEDC there is less damage done because they have better built buildings and the money to clear everything up.
Case study on San Franciso:> Damage caused
< Strategies used to reduce the effects.
Cyprus structure collapsed-Dorothy Otto
During rush hour- 5:04 pm
Section of the Bay Bridge collapsed
46 dead
How can buildings be protected from earthquakes?
They can be built in a special earthquake proof way where they could have reinforced steel beams, they can be built with steel beams underneath the ground so that they would be slightly more sturdy if there would be liquifaction, they can be built out of a stronger concrete and bricks, they can have less glass/thicker glass etc. This is basically a overall stronger structure.
Can you draw a diagram to show the main features of a volcano?
Includes: main vent, crater, ash/lava layers, magma chamber secondry vent and the secondry cone.
Can show: sill, dyke, branch pipe, lava bobms, pyroclastic flow, lava flow etc.
What are the different types of eruptions?
An active volcano, a dormant vaolcano and a extinct volcano.
What is a active volcano?
One that has erupted in living memory.
What is a dormant volcano?
One that has erupted in recorded history.
What is a extinct volcano?
One that hasn't erupted in recorded history and shouldn't erupt ever again.
What are the benefits of living in a volcanic area?
Some of the benefits to living in a volcanic area are that the soil near a volcano is very fertile for crops and plants and this means that you can get more money for them and also in places like Iceland they can make low-costing geothermal energy from the heat that the volcano gives off.
Case study on Mt. St. Helens: >Damage caused
<Strategies used to reduce the effects.
>spring 1980
sunday 8:32 am
53 dead>>> mostly the snow(snow capped mountain) becoming a mudflow
pyroclastic flow for 12 miles
blew sidways
<they had a 5 mile exclusion zone but wasn't big enough.
Case study on Nevada del Ruiz: > Damage caused
< Strategies used to reduce the effects.
>november 1985
20,000+ dead
<Goverment ignored the scientists warnings beacuse house prices would drop and they couldn't afford that.
>Omara Sanchez-60 hours waiting to be rescued-eventually died of heartattack.
Town near by called Amero.
reporters were flown in instead of much needed medical supplies.
What causes a tsunami to happen?
Tsunamis occur when the epicentre/focus is under the ocean. When the earyhquake happens it sends out waves which as the get closer to the shore line become bigger and bigger sucking in all the water they can and the crash down on the land.
What are some of the effects a tsunami can have?
Very high death tolls
thousands of towns and citys just being washed away
billions and billions of £'s worth of money needed to clear up the ruble, mess and to bring in medical supplies, food, water and to rebuild everything back up.
What are the climate characteristics of the Tundra?
Extremly cold climate
simple vegetation
not much rain
What are the climate characteristics of the Desert?
Very very hot!
<500ml rainfall per a year
cold at night
not ggod for vegetation
What are the climate characteristics of the TRF?
rains alot >2500ml per a year
quite a warm temperature- around 30 degrees
very good for vegetation
Decribe the process of shifting cultivation.
The TRFs tribes can't live on the same land forever beacuse all the nutrients in the soil get used up quickly so every 6-7 years the "shift cultivation". This is when the pack themselves up and abondon then place they have been living in and move away from there but still in their territory so that there is no competition with other tribes for things like food supplies etc. then after they have finished there they move again so that they still have fertil soils and plenty of animals to eat. They do sometimes move back to somwhere they have been settled before but they leave it long enough so that it can completely grow back.
What is "slash and burn"
its when people burn down the rest of the vegetation in the rainforest to get a large part of the rainforest cleared.
How has the TRF changed in recent years?
In recent years the rainforest has become a lot smaller beacuse of there being so much deforestation and "slash and burn".
How is the TRF being destroyed? Describe the main threats.
The TRF is being mainly destroyed by humans. The main threats are deforestation, farnibg, logging,cattle ranching, slash and burn and also gold/coal mining.
Should the TRF destrcution be stopped? Why?
Yes because with all of the deforestation happening the air is just being even more polluted by green house ommisions because the rainforest isnt there to turn the Co2 into oxygen.
What is sustainble devlopment? Give examples.
Its when we use the rainforest sustainbly(still preserving) but still meeting the human needs.
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