Volcanic eruptions can produce a variety of materials, but three primary types are commonly identified:
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Lava: This molten rock material flows out of a volcano during an eruption. Lava can vary in composition and viscosity, leading to different eruption styles. There are two main types of lava:
- Pahoehoe: This is smooth, ropy lava that flows easily and creates a relatively gentle surface.
- Aa: This type of lava is more viscous and rough, leading to a jagged surface as it cools and solidifies.
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Tephra: This term encompasses all solid fragments that are ejected during an eruption. Tephra can include various sizes of volcanic material, from fine ash to larger volcanic rocks. The main categories of tephra are:
- Volcanic Ash: Tiny particles less than 2mm in diameter that can be carried far from the eruption site by wind.
- Lapilli: Small volcanic stones between 2mm and 64mm in diameter.
- Volcanic Bombs: Larger, molten or solidified fragments that are ejected at larger sizes, typically more than 64mm.
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Volcanic Gases: Eruptions release various gases, which are significant contributors to the eruptive process and have important environmental impacts. Common volcanic gases include:
- Water vapor (H2O): The most abundant gas released during eruptions.
- Carbon dioxide (CO2): Can be quite hazardous if it accumulates in low-lying areas.
- Sulfur dioxide (SO2): Contributes to acid rain and can have climatic effects.
These materials can vary in their physical and chemical properties depending on the type of volcano and the nature of the eruption.
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