Physical Geography

1. 1. The core heats the molton rock in the mantle which creates a convection current.
   1. 2. The heated rock rises to the surface.
      1. 3. At the surface convection currents move the tectonic plates in the crust.
         1. 4.Molton rock cools and flows back to the core.

Nota:

• Collison Plate boundries - E.g: Indo Australian and Eurasion plates  - two continental plates collide and the two plates buckle - Many Earthquakes

1. Destructive
   1. when 2 plates colilde one flows under the other (subduction)
   2. e.g. Nazca Plate and South American Plate
   3. Earthquakes and volcanoes occour
2. constructive
   1. Rising convection currents pull apart
   2. e.g. Eurasion and North American Plate
   3. forming volcanic ridges e.g. Mid-Atlantic RIdge
3. conservative
   1. Two plates slide past one another
   2. e.g San Andreas Fault California
   3. Earthquakes

1. Earthquake in Kashimer 2005
   1. 75 000 dead
   2. 2.8 million homeless
   3. 75 000 injured
   4. property damage $440 million
2. Earthquake in California, 1989
   1. up too 12 000 homeless
   2. 3757 injured
   3. property damage $10 million
   4. 63 dead

1. shield volcanoes
   1. found on constructive plate boundaries
   2. formed by long thin,runny lava which flows a long way before it solidifies
   3. gentle sloping sides and a wide base
   4. contains baslaltic magma which is very hot with low silica and gas content
   5. Erupts frequently but not violently
2. composite volcanoes
   1. found on destructive plate boundraies
   2. formed by eruptions of viscous sticky lava and ash that don't flow far
   3. have steep slopping sides and narrow base
   4. made up layers of thick lava and ash
   5. contains andesitic magma which is less hot but contains lots of silica and gas
   6. erupts frequently but not violently includes pyroclastic flow

1. they are very difficult to predict

   Nota:

   • - when will they be  - where will it be exactly - how big? - What other impacts will there be - how many people live there - can we evacuate the people
2. what can help predict earthquakes

   Nota:

   • - animals and birds fly away - increase in gas emmisions - increase in soil temperature - volcano swelling - increase in small earthquakes - water ponds getting warmer
3. lots needed after an earthquake e.g. volunteers, clean water

   Nota:

   • - trained volunteers to help clear up debris, injured and dead people - clean water to prevent spread of disease - food as often roads, farms, shops and towns have been effected - radio communication because phones will often not work - medical people to care for the injured - a plan to evacuate the area if needed

1. Social Effects
   1. 58 000 people were evacuate from a 30km radius of the volcano
   2. 874 deaths in total
   3. 300 killed from collapsing roofs
   4. 100 killed by layhars
   5. 1.2 million lost their homes
   6. people round the volcano had to migrate to shanty towns in manila
2. Economic Effects
   1. houses & bridges destroyed and needed replacing
   2. Manila airport had to be closed
   3. 1991 harvest destroyed and 650 000 people lost their jobs
   4. farmland destroyed by falling ash & pumice unusable for years
   5. Heavy rainfalll from Typhoon Yunga causes buildings to collapse
3. Enviromental Effects
   1. Fast flowing volcanic mudflow (Lahars) cause servere river bank erosion undercut bridges etc.
   2. Volcanic ash blown in all directions over hundreds of kms, smothering fields and buildings
   3. Global cooling caused by ash in the atmosphere of 0.5c
4. Where?
   1. Island of Luzon in the Phillipines
   2. SE Asia at the destructive plate boundry between the Eurasion & Philippine Plates
5. Why?
   1. Result of Oceanic Philipine plate being subducted under the lighter continental Eurasion plate
6. What?
   1. Composite Volcano exploded in June 1991 creating Lahars & massive ash & gas cloud
7. Managing the hazard
   1. Prevention
      1. 75 000 people evacuated up to a 30km radius
      2. US Air Force helicopters helped evacuation
      3. Alert Systems put in place to warn of eruption
      4. Government Shelters
      5. Strategies for long term aid and disease control during evacutions
   2. Prediction
      1. 75 000 people were evacuated due to accurate predictions
      2. Set up a permanent monitoring points or use satellite images to look at volcano site for changes in land surfaces
      3. The US Geological Service helped to predict the disaster
      4. No monitoring till April when seisometers were put into place
   3. Prepatation
      1. Evacuation camps built for refugees
      2. Warning sign like gas and steam looked for
      3. Long & short term aid organised especially from the Red Cross and the US
      4. Storage of medical supplies of food and water in preparation for disaster