Question

Match each of the following volcanic landforms with the principle zone of volcanism (convergent plate boundaries, divergent plate boundaries, or intraplate volcanism) with which it is associated: a. Crater Lake e. Yellowstone b. Hawaii's Kilauea f. Mount Pelée c. Mount St. Helens g. Deccan Plateau d. East African Rift h. Fujiyama

Short answer

Crater Lake, Mount Pelée, Mount St. Helens, and Fujiyama are at convergent boundaries. Yellowstone, Hawaii's Kilauea, and Deccan Plateau are from intraplate volcanism. East African Rift is at a divergent boundary.

Step-by-step solution

Understanding Volcanic Landforms

To match volcanic landforms with the principle zones of volcanism, we need to understand the types: - Convergent plate boundaries occur where two plates move towards each other, causing subduction and often creating explosive volcanoes. - Divergent plate boundaries happen where two plates move apart, allowing magma to rise and often creating ridges or rift valleys. - Intraplate volcanism occurs away from plate boundaries, often due to mantle plumes or 'hotspots'.

Analyzing Each Landform

- Crater Lake: Formed from a collapsed volcano at a convergent boundary. - Yellowstone: A result of a hotspot, indicating intraplate volcanism. - Hawaii’s Kilauea: A hotspot volcano, which is typical of intraplate volcanism. - Mount Pelée: Located on a convergent boundary with subduction zones. - Mount St. Helens: Part of the Cascade Range, formed at a convergent boundary. - Deccan Plateau: Formed by flood basalts from a hotspot, indicating intraplate volcanism. - East African Rift: A divergent plate boundary formation. - Fujiyama (Mount Fuji): Located at a convergent plate boundary.

Matching the Landforms with Zones

Now, we will match each landform with its respective zone of volcanism: - Crater Lake: Convergent plate boundary - Yellowstone: Intraplate volcanism - Hawaii's Kilauea: Intraplate volcanism - Mount Pelée: Convergent plate boundary - Mount St. Helens: Convergent plate boundary - Deccan Plateau: Intraplate volcanism - East African Rift: Divergent plate boundary - Fujiyama: Convergent plate boundary

Key concepts

Convergent Plate Boundaries

When talking about convergent plate boundaries, it's all about how Earth's tectonic plates collide. These zones are home to some of the most explosive and powerful volcanic eruptions seen worldwide. Let's explore why that happens.
When two tectonic plates move toward each other, one of them usually slides underneath the other in a process called subduction. This sliding action occurs because plates are dense, and some are heavier than others.
As the heavier plate subducts, it melts due to pressure and heat. This melting forms magma, which is less dense than the surrounding rock, so it rises to the surface, causing volcanic activity.
Volcanoes formed at convergent boundaries can be quite explosive because the rising magma is often thick and sticky (andesitic or rhyolitic), trapping gases that lead to explosive releases.

• Examples: Mount St. Helens and Fujiyama are both classic volcanoes situated at convergent boundaries.
• Formation: Subduction zones lead to the melting of mantle material, creating magma that rises to form volcanoes.
• Characteristics: Eruptions at these boundaries tend to be violent, producing massive ash clouds and pyroclastic flows.

Divergent Plate Boundaries

Divergent plate boundaries are fascinating locations where new crust is continuously being formed. This process results in some unique volcanic features and activities.
At divergent boundaries, tectonic plates are pulling away from each other. This separation creates gaps that allow magma from the mantle to rise and fill the space, forming new crust as it cools and solidifies.
This geologic activity leads to the formation of mid-ocean ridges or continental rifts, depending on their location. Volcanism at these boundaries is generally less violent, with lava flows being more common than explosive eruptions.

• Examples: The East African Rift is an excellent example of a divergent plate boundary on land.
• Formation: As the plates diverge, underlying magma rises to fill the created space, forming new crust.
• Characteristics: Volcanic features here include rift valleys and oceanic ridges, with basaltic lava flows being frequent.

Intraplate Volcanism

Intraplate volcanism happens in places that aren't located at plate boundaries, which might sound surprising at first. These volcanic activities are primarily driven by hotspots.
A hotspot is an area in the mantle from which heat rises in the form of a thermal plume. Such plumes can generate intense volcanic activity when they reach the Earth's crust, even though they aren’t near any plate boundary.
Hotspots are stationary relative to the moving tectonic plates above them, creating volcanic island chains as the plates move over the plume.
The lava associated with intraplate volcanism is typically fluid and basaltic, resulting in less explosive and more flowing eruptions.

• Examples: Yellowstone and Hawaii's Kilauea are well-known hotspots.
• Formation: Rising plumes of hot mantle material create magma that pierces through the crust to form volcanoes.
• Characteristics: Volcanic islands and expansive plateaus are common, with eruptions producing vast lava flows.