Tectonics 1.8 - Destructive plate boundaries (Chile con Carnage)

What happens in subduction zones that leads to explosive eruptions?

• The oceanic crust simply cools and solidifies

• Pressure builds before an explosive eruption due to higher silicates and gas content in magma

• Lava flows build up into steep-sided volcanoes

• Moisture-rich air cools and condenses

What is a characteristic of the lava in destructive plate lava flows?

• It is less viscous and travels far before cooling

• It cools quickly and forms flat landscapes

• It is viscous and does not travel far before cooling

• It is associated with the formation of wide, shield volcanoes

How do earthquakes contribute to the formation of landslides?

• They cause the Pacific Ocean to rise up over the Andes

• They create moisture-rich air that condenses into clouds

• They result in high stress in the Earth's crust, leading to landslides

• They reduce the pressure between tectonic plates, preventing landslides

What geological feature is formed by the uplift and folding of continental crust at destructive plate boundaries?

• Deep ocean trenches

• Fold mountains

• Wide river valleys

• Large desert basins

What effect does the moisture-rich air from the Pacific Ocean have when it rises over the Andes?

• It causes explosive volcanic eruptions

• It leads to the formation of deep ocean trenches

• It cools, condenses, and forms precipitation at the peaks

• It increases the viscosity of lava flows

Why are shallower earthquakes considered more dangerous in terms of energy reaching the surface?

• They release less energy than deeper earthquakes

• They occur more frequently than deeper earthquakes

• They allow more energy to reach the surface

• They are less detectable than deeper earthquakes

What is the thickness of the Nazca Plate at the destructive (convergent) plate boundary?

• 50 km

• 7 km

• 30 mm

• 700 km

What is the subduction rate of the oceanic plate at the destructive (convergent) plate boundary?

• 50 mm/yr

• 30 mm/yr

• 100 km

• 700 km

What geological feature is formed due to the uplift and orogeny at the convergent plate boundary?

• Volcanoes

• Batholith

• Fold mountains (Andes)

• Accretion wedge

What causes the melting of crustal rocks in the Benioff zone?

• Slab pull

• Convection

• Hydration melting (water involved lowers melting temperature)

• Accretion wedge