1. What is the lecture mainly about?
- A. The recent discovery of an unusual tectonic plate
- B. The effects of underwater riffs on plate boundaries located on land
- C. The development of a new technology for studying rifts located on land
- D. The process by which tectonic plates are separated
2. Why does the professor mention Iceland?
- A. To support the claim that rifts occur wherever volcanoes occur
- B. To point out that Iceland is located on a plate boundary
- C. To give an example of a rift area that is located on land
- D. To give an example of an extraordinary active rift system
3. What unexpected discovery did scientists make while studying the rift event in East Africa?
- A. Rifts can widen more quickly than previously thought.
- B. Some magma deposits lie closer to Earth surface than geologists realized.
- C. Volcanic activity is not necessary for rift formation.
- D. Volcanic activity along land rifts is different from activity along underwater rifts.
4. In the lecture the professor discusses an event that occurred along a rift in East Africa. Place the stages of this event in order.
- A. Molten rock flowed into the rift and widened it.
- B. There was a brief period of inactivity.
- C. Seismic activity began 30 kilometers south of the northern volcanoes.
- D. There was a series of earthquakes near the northern volcanoes.
5. According to the professor, what may eventually occur at the location of the recent rift event in East Africa?
- A. Two tectonic plates will merge.
- B. A deep basin will form.
- C. A new fissure will open.
- D. Underground earthquakes will become more frequent.
6. What does the professor imply when he says this: 🎧
“But then, in the eastern part of Africa is a complex system of rifts called, shockingly enough, the East Africa rift system.”
- A. The East Africa Rift System is much larger than previously thought.
- B. “East Africa Rift System” is an obvious name for the system.
- C. The East Africa Rift System is not actually a system.
- D. Not all of the East Africa Rift System is located in Africa.