Question

Plate Tectonics: Our Restless Planet

Video Questions
1. How do scientists indentify tectonically active regions?
2. How many major plates compose Earth's surface?
3. Why is the crust of Earth barely visible on scaled drawings? How does it's
thickness compare with Earth's other layers?
4. How do rifts form? Where do rifts usually occur?
5. What is the Mid-Atlantic Ocean Ridge? How does it affect the Atlantic Ocean?
How does it affect America and Africa?
6. What is subduction? Why is it important?
7. What causes oceanic trenches?
8. How do mountains form?

Answer 1

Plate tectonics are identified using seismic activity, there are 7 major plates, the crust is thin compared to other layers, rifts occur due to plate movement, the Mid-Atlantic Ocean Ridge affects the ocean and the continents, subduction leads to recycling of old crust and mountain formation, oceanic trenches are caused by subduction, and mountains can form through folding, faulting, vulcanism, and erosion.

Step-by-step explanation:

Plate Tectonics: Our Restless Planet

1. Scientists identify tectonically active regions by monitoring seismic activity, such as earthquakes and volcanic eruptions. These events indicate that the Earth's tectonic plates are moving and interacting.
2. There are 7 major plates that compose Earth's surface: the African Plate, Antarctic Plate, Eurasian Plate, Indo-Australian Plate, North American Plate, Pacific Plate, and South American Plate.
3. The crust of the Earth is barely visible on scaled drawings because it is very thin compared to the other layers. The crust has an average thickness of about 35 kilometers, while the Earth's other layers, such as the mantle and core, have much greater thicknesses.
4. Rifts form when tectonic plates pull apart, creating a gap or fissure. Rifts usually occur in areas where there is a divergent boundary, such as the Mid-Atlantic Ocean Ridge.
5. The Mid-Atlantic Ocean Ridge is a mountain range that runs through the Atlantic Ocean, dividing it into two halves. It affects the Atlantic Ocean by creating a boundary between the plates, where new crust is continuously being formed. It also affects America and Africa by slowly pushing them apart as the plates diverge.
6. Subduction is the process where one tectonic plate moves under another plate at a convergent boundary. It is important because it leads to the recycling of old crust back into the Earth's interior, and it can cause volcanic activity and the formation of mountain ranges.
7. Oceanic trenches are caused by the process of subduction. When one plate moves under another plate, it creates a deep trench in the ocean floor.
8. Mountains can form through several processes, including:
   • Folding: when rocks are compressed and bent, creating folds and anticlines/synclines.
   • Faulting: when rocks are fractured and displaced along a fault line, creating uplifted blocks and valleys.
   • Vulcanism: when molten rock or magma rises to the surface, creating volcanic mountains.
   • Erosion: when forces like wind, water, and ice wear away the Earth's surface, exposing underlying rock layers and creating mountains.

Learn more about Plate tectonics