Question

1. describe the process of seafloor spreading.
2. how does new ocean floor add to tectonic crust?
3. what is a rift?
4. what is a fault?
5. explain how earthquakes are formed.
6. which two plates meet at the san andreas fault?

click plates interactions challenge
case 1: africa

1. what is happening at the plate boundary where the african and the arabian plate meet?
2. what geological event is most likely to occur at this plate boundary in the future?

case 2: new zealand

1. what is happening at the plate boundary where the australian and the pacific plate meet?
2. what geological event is most likely to occur at this plate boundary in the future?

case 3: south america

1. what is happening at the plate boundary where the nazca and the south american plate meet?
2. what geological event is most likely to occur at this plate boundary in the future?

Explanation:

1. Sea - floor spreading occurs at mid - ocean ridges. Magma rises up, cools and solidifies to form new oceanic crust, pushing the existing crust away from the ridge.
2. New ocean floor forms at mid - ocean ridges through sea - floor spreading. Magma wells up, solidifies and adds to the oceanic crust.
3. A rift is a linear zone where the Earth's crust and lithosphere are being pulled apart.
4. A fault is a fracture or zone of fractures between two blocks of rock, which can result in relative movement of the blocks.
5. Earthquakes form when stress on rocks along a fault builds up and is suddenly released, causing the ground to shake.
6. The North American Plate and the Pacific Plate meet at the San Andreas Fault.
7. At the boundary where the African and Arabian Plates meet, it is a divergent boundary. New crust is being formed as the plates move apart.
8. Earthquakes and volcanic activity are likely to occur at this divergent plate boundary in the future.
9. At the boundary where the Australian and Pacific Plates meet, it is a convergent boundary. One plate is subducting beneath the other.
10. Earthquakes and volcanic activity are likely to occur at this convergent plate boundary in the future.
11. At the boundary where the Nazca and South American Plates meet, it is a convergent boundary. The Nazca Plate is subducting beneath the South American Plate.
12. Earthquakes and volcanic activity are likely to occur at this convergent plate boundary in the future.

Answer:

1. Magma rises at mid - ocean ridges, cools and solidifies to form new crust, pushing existing crust away.
2. Magma wells up at mid - ocean ridges during sea - floor spreading to form new ocean floor.
3. A linear zone where the crust and lithosphere are being pulled apart.
4. A fracture or zone of fractures between two rock blocks allowing relative movement.
5. Stress on rocks along a fault builds up and is suddenly released.
6. North American Plate and Pacific Plate.
7. It is a divergent boundary; new crust is forming as plates move apart.
8. Earthquakes and volcanic activity.
9. It is a convergent boundary; one plate is subducting beneath the other.
10. Earthquakes and volcanic activity.
11. It is a convergent boundary; the Nazca Plate is subducting beneath the South American Plate.
12. Earthquakes and volcanic activity.