Plate Tectonics Theory Quiz

Tectonic plates in the earth's crust move because _________.

• of the formation of plate boundaries

• they are being pulled by earth's gravity

• they lie on top of the asthenosphere where they moved by the convection current

• of faults, volcanoes and trenches that are affected by earthquakes and plate movements

When a continental and an oceanic crust collide, the oceanic crust dives down under the continental crust as shown by the figure. Which statement best explains this observation?

• the oceanic crust is denser than the continental crust

• the continental crust exerts pressure on the oceanic crust

• the weight of the continental crust pushes down the oceanic crust

• the top portion of the oceanic crust is wet so it tends to slide down the continental crust

If the Atlantic Ocean is widening at a rate of 3 cm per year, how far (in kilometers) will it spread in a million years?

• 3 km

• 30 km

• 300 km

• 3000 km

Which of the following can you infer from the continuous movement of the lithospheric plates over the asthenosphere?

• All the continents will cease to exist.

• All the volcanoes in the Philippines will become inactive

• The continents will not be located in the same place as they are now.

• The islands of the Philippines will be scattered all over the world.

As a new seafloor is formed at the mid-ocean ridge, the old seafloor farthest from the ridge is destroyed. Which of the stated processes describes how the oceanic crust plunges into the Earth and destroyed at the mantle?

• convection

• construction

• diversion

• subduction