lesson 3: volcanic eruptions

• Active volcanoes have a recent history of eruptions; they are likely to erupt again
• dormant volcanoes have not erupted for a very long time but may erupt at a future time.
• extinct volcanoes are not expected to erupt in the future.
• lava flows typically move slowly enough to outrun them, but they will destroy everything in their path
• pyroclastic flows are volcanic phenomena that involve high-density mixtures of hot, fragmented solids and expanding gases
• ballistic projectiles - fragments of solids (blocks) or fluid (bombs) material ejected during the range of magmatic or phreatic (steam) explosive eruptions.
• lahar are mudflows created when water and volcanic ash mix
• Volcanic gases are composed mainly of water, carbon dioxide, and sulfur dioxide. emitted by active volcanoes