Calderas

A caldera is a large volcanic crater formed by the collapse of a volcano following an eruption. The collapse occurs when the magma chamber underlying the volcano is emptied during an eruption, causing the unsupported rock above to fall into the emptied space, creating a large depression.

Formation of Calderas

Calderas can form through various processes, including:

• Explosive Eruptions: These eruptions release large amounts of volcanic material, causing the overlying rock to collapse into the emptied magma chamber.
• Subsidence: Gradual sinking of the ground due to the withdrawal of magma from the chamber.
• Collapse of lava dome: When the lava dome on the top of a volcano collapses into the emptied chamber, it can create a caldera.

Types of Calderas

There are several types of calderas based on their formation and characteristics:

• Resurgent Calderas: These are large, steep-walled calderas that experience renewed uplift of the caldera floor after the initial collapse.
• Subsidence Calderas: These calderas form through gradual subsidence of the ground following the withdrawal of magma from the chamber.
• Volcanic Calderas: Formed by the collapse of the summit of a volcano following a large explosive eruption.

Impact and Hazards

Calderas can have significant impacts on the surrounding environment, including the formation of geothermal features such as hot springs and geysers. However, they also pose hazards such as the potential for future eruptions, landslides, and lahars (mudflows).

Study Guide

To study calderas, it's important to understand the following key points:

1. Formation processes of calderas, including explosive eruptions and subsidence.
2. Characteristics and types of calderas, such as resurgent, subsidence, and volcanic calderas.
3. Understanding the hazards and impacts associated with calderas, including potential future eruptions and related geological phenomena.