15 Questions
What is the main reason why pyroclastic density currents associated with volcanic eruptions have a decreased capacity to travel away from the volcano?
There are fewer solid particles, allowing the gas to dissipate more quickly.
Which of the following is a key difference between pyroclastic flows and tephra?
Pyroclastic flows often contain high amounts of solid fragments, while tephra refers to large chunks of rocks and debris.
What was a major consequence of the tephra produced during the 1815 eruption of Tambora volcano in Indonesia?
The tephra destroyed the vegetation on nearby islands, leading to the loss of food supplies for thousands of Indonesians.
What is a key characteristic of tephra that makes them extremely destructive?
Tephra can be larger than cars in size and weigh upwards of 8 to 30 tons.
Which of the following is an example of a pyroclastic surge event that resulted in significant loss of life?
The 1902 eruption of Mount Pelee that destroyed the city of Saint Pierre and killed more than 29,000 people.
What type of tectonic plate boundary is responsible for most of the volcanic activity on Earth?
Convergent plate boundaries
Which type of volcano is characterized by round, dome-like structures with gentle slopes?
Shield volcano
What term is used for molten rock that remains beneath the surface of Earth?
Magma
Which type of volcano is marked by the presence of calderas and multiple vents through which lava can flow?
Stratovolcano
Besides molten rock, what other types of materials can volcanoes eject?
Steam, clouds of molten ash, and super-heated rock fragments
What distinguishes a pyroclastic flow from a lava flow?
Pyroclastic flows contain more solid particles than lava flows.
Why are pyroclastic surges able to travel at faster speeds compared to pyroclastic flows?
Pyroclastic surges have decreased density due to being largely comprised of gases.
What is the speed at which pyroclastic flows can move?
450 miles per hour
How do lava flows compare to pyroclastic flows in terms of composition?
Pyroclastic flows contain more rock fragments than lava flows.
What distinguishes a pyroclastic surge from a pyroclastic flow?
Pyroclastic surges are composed of gases, while pyroclastic flows are solid.
Explore the impressive and destructive geological features of volcanoes and their association with Earth's tectonic plates. Learn how intense heat and pressure at divergent plate boundaries lead to the formation of volcanoes.
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