Tectonic Hazards

Tectonic Hazards...

• Oceanic crust: 
• 60% of Earth's crust.
• Thin and young, no more than 20k thick.
• Born at mid - ocean ridges where plates are pulled apart. 
• More dense

• Continental crust: 
• Thick and old - 50k thick, 2 billion years old. 
• Granitic rocks
• When continents collide, it can thicken to 100k. 
• Less dense

1) A tectonic plate is moving faster than the other

2) They collide

3) It subducts into the mantle

4) Driving force will pull plate under

(Not a fast procces)

1) Magma near outer core is heated

2) As the magma warms it expands and becomes less dense

3) The less dense magama begins to rise towwards the crust

4) As it nears the crust it cools

5) The cooling magama becomes more dense and begins to sink

6) The rising and falling magma creates circular currents with the mantle

7) The currents create friction with the above crust and causes it to move

A gap is formed, A volcano development is constructed!

The Oceanic plate subducts as it's more dense. It then melts due to friction

Friction when sliding causes earthquakes, no volcanoes made as no magma involved.

Worst ones occour at conservative and destructive!!

• Focus - Point underground where quake occours. Burst of energy is released, the closer to earths surface the bigger the impact. 
• Epicentre - location on surface, directly above focous.
• Seismic waves - waves of energy from quake, through the rock to surface
• Afterschocks - smaller tremours days after quake.
• Rhichter scale - measures magnitude on a scale of 0 to 10.

HAITI EARTHQUAKE, 2010 - LIC

• Jnauary 12, 2010
• 4:53pm - rush hour!
• North American and Carribean plate moved (Conservative)
• Magnitude 7 
• 1 million died
• Main prison collapsed - 4,000 in mates escaped!
• Govournmnet building destroyed
• Aftershocks - magnitude 5.5 and 5.9
• Epicentre was 15km from Paut - Au - Prince.

• Buidings destroyed
• Gas pipes burst
• transport blocked
• 86% living in slums made homeless immidiatley. 
• people trapped
• airport runway damaged
• control tower fell down...
• comms lines destoryed
• homelessness :(

• Cholerea
• 1.5 million homeless
• camps set up - 810, 000 people moved into them.
• looting and violence
• children without parents :(
• 1 in 5 unemployed
• residents living off $2 per day!! 
• aid was EVENTUALLY given.
• Airport closure
• 600,000 people left their homes. 
• free medical care to 39,000 people.
• Poor sanitation, no clean water, waste disposal. 
• Unicef helped build hospitals, schools, airport, housing.
• $100 million given by U.S
• $330 million given by European Union.

JAPAN EARTHQUAKE, 2011 - HIC

80 miles off Monshu on the N.E coast.

• Magnitude 8.9 
• Most powerful in Japan
• 4th most powerful in world
• Struck at 2:45pm - normal working day!
• Triggered a Tsunami - 20ft and 500mph!!! 
• Children at 4 or 5 years old had been taught - Duck, Cover, Hold
• 4 nuclear power stations closed
• Sendai runway flooded
• Buses and trains suspended
• After schock in North
• Pacific and Phillipean sea involved, and continental plate. 

Date - 11 March

Plates - Pacific plate forced under N.American plate, destructive. 

Aftershocks - 900 aftershocks, 7.6 magnitude, 1 week after earthquake. 

Primary affects - 5.6 million buildings destroyed, Sendai airport runway flooded, 4 trains dissapeared, fires broke out, Air force base flooded, 1 million homes without water, ships dumped on shore, thousands dead, Tokyo's 2 major airports closed. 

Secondarry affects - Gas flow stopped, Chaos at Tokyo airport, thousands of people evacuated around Fukishima nuclear reactor, Trains stopped, manu made homeless for weeks, Supermarkets ran out of food, Toyata and other major companies stopped production. 

• Most Earthquake aware country. 
• Strong steel and concrete structures.
• Gas flow stopped. 
• Trains stopped automatically. 

Was it predicted?

Yes! The atmosphere above experienced unusual changes. 

• How well did they protect population? 
• Sirens for tsunami
• fire station doors open automatically when tremours felt
• Emergency kits in Houses and schools!

• Predict - 
• Water levels in wells and lakes can rise as rocks crack
• tiltmeter detecting movement in rocks
• Animals can act strange beforehand
• foreshocks before main quake - measured using a seismometer

• Plan and Protect - 
• Provide open areas
• Kids get taugh, drop, cover, hold.
• schools have quake drill every year (H.I.C)
• Earthquake proof buildings - deep foundations, shock absorbers, flexible gas and water mains.
• emergency supplies in a city (water tanks) 
• households to plan and have emergency equipment - radio, phone, lots of food, water, disposal system (toilet paper, bins), torch, batteries, watch, first aid equipment

Rolling weights - conteract shcok waves

Walls - steel and concrete

Dampers - absorb shaking

Overlapping bricks, stronger.

e.g - Tokyo sky tower - Built to shake with staircase as central coloumn

San Andreas Fualt (San Fransisco) - Triangulr bases, deep foundations, base isolation (keeps buildings off ground and buildings can sway), concrete. 

Tsunami walls - protect towns and cities, not so effective when a 500mph wave comes flying at them!! Best thing to do is go to highland.

• not enough money (L.I.C)
• Feel protected enough to withstand a hazard
• Family and friends
• Tourism (Volcanoes)
• Elderly
• Fertile soil (Volcanoes), good for farming!

Advanteges of living in a hazardous area can sometimes outweigh negatives!!

(The End, phew now u may take a breather!! AHhh)