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Listen to an Academic Talk Test #029
Listen to an Academic Talk
1. What is the lecturer's main purpose?
A) To compare different types of volcanoes
B) To explain the formation of volcanoes far from plate boundaries
C) To describe the movement of tectonic plates
D) To discuss the geology of the Hawaiian Islands
2. According to the lecturer, what causes a hotspot volcano to become extinct?
A) The hotspot itself cools down and disappears.
B) It runs out of magma from the Earth's core.
C) The volcano's own eruption destroys it.
D) The movement of a tectonic plate carries it away.
3. What can be inferred about the oldest island in the Hawaiian chain?
A) It is currently the most volcanically active.
B) It is located farthest from the hotspot.
C) It is the largest island in the chain.
D) It is still located directly over the hotspot.
4. Why does the lecturer mention the Hawaiian Islands?
A) To show that most volcanoes are at plate boundaries
B) To challenge a common theory about hotspots
C) To provide a clear example of a hotspot volcano chain
D) To discuss the environmental impact of volcanoes
Lecturer: Most volcanoes are found at the boundaries of tectonic plates, where plates are either colliding or pulling apart. But some volcanoes, like the ones that formed the Hawaiian Islands, are located thousands of kilometers away from any plate boundary. These are called hotspot volcanoes.
A hotspot is a fixed area in the Earth's mantle that is unusually hot. This intense heat causes mantle rock to melt, forming magma, which then rises to the surface and erupts, creating a volcano. Because the tectonic plate above the hotspot is constantly moving, the volcano is eventually carried away from the hotspot's magma source and becomes extinct.
Meanwhile, a new volcano begins to form on the part of the plate that is now over the hotspot. This process, repeated over millions of years, creates a chain of islands, like the Hawaiian chain. So studying these chains gives us a direct record of how tectonic plates have moved over time.
A hotspot is a fixed area in the Earth's mantle that is unusually hot. This intense heat causes mantle rock to melt, forming magma, which then rises to the surface and erupts, creating a volcano. Because the tectonic plate above the hotspot is constantly moving, the volcano is eventually carried away from the hotspot's magma source and becomes extinct.
Meanwhile, a new volcano begins to form on the part of the plate that is now over the hotspot. This process, repeated over millions of years, creates a chain of islands, like the Hawaiian chain. So studying these chains gives us a direct record of how tectonic plates have moved over time.
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