1.9 - Chile Flashcards
Features of shield volcanoes
- constructive plate boundary
- divergence
- lower silicates and gas content in magma
- continuous eruption, pressure release
- calmer eruption - gas and lava
- runny basaltic lava, gentle slope, shorter volcano
Features of composite volcanoes
- destructive plate boundary
- subduction
- higher silicates and gas content in magma
- longer dormancy, pressure build-up
- explosive eruption, gas and material
- viscous andesitic lava, steep sided, tall volcano
What type of plate boundary does Chile (the Andes) lie on?
Convergent plate boundary
Chile lies in the Pacific Ring of Fire - What is it?
The Ring of Fire is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur.
What plate is below the South American Plate?
Nazca Plate / Antarctic Plate
What can EQ’s trigger?
Avalanches, rock avalanches and landslides
Name some stresses
- angle of slope
- rainwater / saturation
- vibration, e.g. car
- earthquakes
- sea, cliff erosion
Name some strengths
- lubricant layers
- tree / vegetation roots
- consolidation of material
- porosity of soil
What are The Benioff Zones?
- an area of seismicity / slab moving downwards
- speed and movement of rock produces earthquakes
- locked faults are the most significant concern - frictional resistance is greater than stress - i.e stuck
- eventually releases in ‘Andean’ earthquakes / huge tsunamis
Stress or strength - Change the focal depth - creates higher moment magnitude
Stress
Stress or strength - Change moment magnitude - stress will exceed strength
Stress
Stress or strength - Change the amount of folding - make the slop steeper
Strength
Stress or strength - make the slope higher - avalanches / freeze-thaw rock breakdown will be higher
Stress
Stress or strength - Higher mountain uplift - more likely to have precipitation
Stress
Stress or strength - make EQ further apart - more energy built up
Stress
