Tectonics Flashcards
What is the structure of the earth?
Crust: hard outer shell
Mantle: soft molten rock
Outer Core: Liquid iron and nickel
Inner Core: Solid Boiling
What’s the differences between oceanic and continental Crust
Oceanic: 5-10km
Dense
Sinks in mantle
Not as old (constantly forms)
Continental: 25-100km
Less dense (Doesn’t sink)
Very old
What happens at Constructive Boundaries?
- Plates move away
- Magma rises and cools
- Constructs new land and volcanos
What happens at Destructive Boundaries?
- Plates move towards eachother
- Oceanic plate sinks under the continental causing friction and magma to rise
- Fold Mountains and Volcanos are made
- Slips cause earthquakes
What happens at collision boundaries?
- Plates move towards eachother
- sediment is compressed into rock
- Rock is forced upwards to form fold mountains
- there is earthquake activity
What happens at Conservative Boundaries?
- Plates move next to eachother
- They move at different speeds so frictions builds up
- When released can create violent earthquake activity
Composite and Shield Volcanos
Composite: Destructive
Steep sides
Pyroclastic flow
Shield: Constructive
Low shallow
Lava is runny
Monitoring and Predicting volcanos
ElectronicTiltMeter: shape
Seismometer: rumbling as magma flow
Sulphur Dioxide emissions
Montserrat Background and Caused
Caribbean UK island
Destructive boundary
first tremors 1992, Eruptions 1995 and 20 yrs later
Pyroclastic flow lasted 2 years
Effects of Montserrat
2/3 covered in ash
5mill m lava
destroyed coral reefs and acid rain
Government breakdown
Houses and Villages destroyed (75% relocated)
4km covered in pyroclastic flow
Responses to Montserrat
Evacuation of 2/3
British government have £41 mill
Volcano observatory
expansion of jobs and tourist resort
Super volcano Background and Causes
last eruption 640000yrs
6.5 km below the surface
64km wide magma chamber
Magma blocked from crust, pressure builds up so much that surface is blown away creating a caldera
SuperVolcano effects
1000km lava
50km high
all life in a 1000km radius would die
Cover the whole of US in 12.5cm thick lava
ash would reduce radiation from sun
ice age
What causes Earthquakes?
When plates try to move they often get stuck and frictions begins to build up
When this pressure is released suddenly it can cause massive shockwaves to be sent out
Kobe (MEDC) Background and Causes
Japan 16th Jan 1995
- 2 on the Richter scale
- 5 million people
$71 billion worth of cargo a year
Effects of Kobe
200,000 buildings destroyed
1km expressway collapsed
120-150 quays destroyed
230,000 left homeless
5500 dead, 40000 injured
Kobe responses
80% facilities working in a year
£56 billion damage
regular earthquake drills
buildings made earthquake proof
Haiti (LEDC) Background and causes
Caribbean Island
Destructive plate
7.0richter scale, 12th Jan 2010
Epicentre 25km away from port au prince
There had been no earthquakes in living memory
had a weak government
overcrowded and homes built badly
Haiti Effects
220,000 killed
300,000 injured
Port, streets, roads, buildings damaged
100,000homes destroyed(1.3homeless)
2mill without food or water
shanty towns created and disease spread
Haiti responses
Immediate:
- team of engineers
- us sent $100 mill
- us and un sent troops
- UN sent food for 2 million
- 235000 moved from port-au-prince
Long term:
- dependent on overseas aid
- new homes cost billions
- large scale investment needed
What causes a Tsunami?
displacement of sea beds due to underwater earthquake
a large wave moved through ocean
high speeds in deep water
slow in shallow water but increase in size
Boxing Day Tsunami Causes
epicentre of the coast of Sumatra
26th December 2004
9.0 and 9.3 on the Richter scale
Boxing Day effects
12 countries effected
236,169 declared dead in Indonesia
70% of the coastal population dead
SE India effected worst
Responses Boxing Day Tsunami
Clean water, food and tents arrived as aid
$7 billion donated worldwide
£330 million by UK public
1.3 received food from UN
Tsunami system set up, formal warnings sent out
Bells, megaphones and all media devices
restore the mangroves
Economics in tectonic areas (Iceland)
Geothermal Energy
Tourism
Agriculture
Industry
