Composite volcanoes, also known as stratovolcanoes, are known for their unique features that distinguish them from other types of volcanoes. Here are five key characteristics:
- Steep Slopes: Composite volcanoes typically have steep, conical shapes due to the layering of lava flows, ash, and other volcanic debris. This steep slope is a result of the highly viscous lava that solidifies and builds up near the vent.
- Explosive Eruptions: These volcanoes are known for their explosive eruptions. The thick lava does not flow freely, leading to pressure build-up in the magma chamber. When the pressure is released, it can result in violent eruptions, often ejecting ash and pyroclastic flows.
- Layered Structure: Composite volcanoes are characterized by their layered structure. Over time, they build up in alternating layers of lava flows and tephra (volcanic ash and rock fragments), which creates a stratified appearance. This layering is a direct result of alternating explosive and effusive eruptions.
- Presence of Craters: At the summit of composite volcanoes, you will often find craters formed by previous eruptions. These craters can vary in size and can be filled with lava lakes or other volcanic materials.
- Gas Emissions: Composite volcanoes often emit gases, including steam, carbon dioxide, and sulfur dioxide. These gases can indicate volcanic activity and contribute to the formation of acidic rain, which can impact the surrounding environment.
Understanding these characteristics is essential for monitoring these volcanoes, which pose risks to nearby communities during eruptive events.