The earths crust 1
Broken into slabs of rock: Tectonic plates
Seven major plates several smaller
The 'float' on mantle rock
Two types of plates Oceanic and Continental
Fold mountains are formed when two plates collide
Exampes of these: Alps, Andes, Rockies and Himalayas
Used by people: settlement, tourism, forestry and farming
Plate boundaries are where tectontic plates meet
Constructive boudary new crust is formed minor earthquakes occur when plates move and volcanis activity.
The earths crust 2
Collision boundary plates buckle and form fold mountains powerful earthquakes no volaconos
Destructive boundary ocenaic crust dense forced down and melts explosive volcanoes and powerful earthquakes.
Conservative boundary plates become locked, plates move suddenly causing powerful earthquakes
Caused by movements of the earths crust.
Earthquakes may occur along fault lines in the crust.
The earhquake focus is called the epicentre.
Primary effects: Buildings collapse, bridges and roads collapse, signs and glass brake/fall.
Secondary effects: Fires, Water cut off, Access difficult, Diseases spread, Tsunami waves.
Long-term effects: Unemployment, Homelessness, Economic damage, Emotional damage
Not possible to predict
Earthquake resistand buildings
pakistan, 8th october 2005, 7.6 on the rictor scale, 73000 deaths, 3million homeless, 3billion for repairs ect. pakistan is on a collision boundary between the eurasian and indo-australian plates
Case study 2..
Japan, 17th january 1995, 7.2 on the rictor scale, 5000 deaths, 300000 homeless, 80 billion for repairs ect. Japan is on a destructive plate boundary between the philippine plate and the eurasian plate.
Two types Sheild and Composite
sheild:constructive plate boundaries, magma rises to fill the gap gentle eruptions e.g. iceland
Composite: Destructive plate boundaries, oceanic crust melted, magma forces way up very explosive e.g. mount st helen USA.
can predict volcanoes
hazard maps drawn
lava flows can be diverted by spraying them with water.
Benefits of living on tectonic plate boundaries: fertile soils, Geothermal energy, tourism, Minerals
Effects of eruption: Pyroclastic flow, Mudflow, Lava flow, Ash fall, Global climate