Volcanoes

• A crater refers to the depression at the summit of most volcanic cones.
• Pyroclastic flow is a rapid downhill movement of hot, solid, volcanic particles suspended in steam.
• Lahar is a mudslide caused by a volcano.
• Volcanoes are composed of igneous rocks.
• Tephra refers to rock fragments and particles ejected during a volcanic eruption.
• VEI, or Volcanic Explosivity Index, is a scale used by geologists to classify the destructiveness of a volcanic eruption.
• The geothermal gradient indicates the rate at which temperature changes with depth underground.
• Viscous lava has a higher silica content compared to runny lava.
• Pyroclastic flows result in more fatalities than flowing lava during volcanic eruptions.
• Magma that emerges onto the Earth’s surface is called lava.
• Glowing avalanches are a type of gaseous emission
• Lava, pillow lava, pahoehoe, and 'a'a are types of liquid emission
• Fumarole emissions are a type of gaseous emission
• Tephra is a solid emission
• All volcanic emissions are a form of extrusive volcanism.
• A scientist's worldview influences their classification of a volcano by activity.
• Volcanoes are depositional mountain landforms constructed from solidified magma originating deep within the earth.
• Rhyolitic magma contains more than 63% silica, classifying it as felsic, light in color, with high viscosity; an example is granite.
• Basaltic magma contains less than 52% silica, classifying it as mafic, dark in color, with low viscosity; an example is basalt.
• Pompeii worms thrive in hydrothermal vents where scalding water rises through crustal rifts in mid-ocean ridges.
• Hot Springs and Geysers are examples of hydrothermal circuits.
• The ash cloud from the Mount Tambora volcano cooled global temperatures and caused what is known as the “year without summer” in 1816.
• Ice core analysis involves studying ice samples to understand past climate and atmospheric conditions.
• Analyzing ash and soil samples helps determine a volcano's chemical composition and eruption type based on depth.
• Sea life analysis can be done by assessing oxygen levels, temperature changes, and observing the diversity of marine life.

This lesson covers key facts related to volcanoes. It Includes information about volcanic eruptions, lava types, and volcanic emissions. It also includes facts about the Volcanic Explosivity Index.