What is a volcano?
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A volcano is an opening in a planet's surface or crust that allows hot, molten rock, ash, and gases to escape from below the surface, often forming mountains over time.
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What is a volcano?
A volcano is an opening in a planet's surface or crust that allows hot, molten rock, ash, and gases to escape from below the surface, often forming mountains over time.
Where are volcanoes commonly found?
Volcanoes are commonly found where tectonic plates pull apart (divergent boundaries) or come together (convergent boundaries), and also where the Earth's crust is stretching and thinning.
What is the difference between extrusive and intrusive volcanic activity?
Extrusive activity involves magma flowing out onto the surface as lava or exploding into the atmosphere, while intrusive activity involves magma solidifying below the surface.
What is the vent of a volcano?
The vent is the narrow opening of a volcano through which material is ejected.
What is a crater in a volcano?
The crater is a cup or saucer-shaped depression at the top of the vent.
What is a fissure volcano?
A fissure volcano is formed when material is ejected through a long crack-like opening in the Earth's surface.
Describe the internal structure of a volcano.
The internal structure includes a magma chamber, main vent, branch pipes, and a cone built up by successive layers of lava and ash.
Why does volcanic material become molten and rise to the surface?
When the pressure of overlying rocks is released (due to faulting, fissures, or gas pressure), the solid-like material turns molten and rises to the surface, causing an eruption.
How long do typical volcanic eruptions last?
Typical volcanic eruptions last only a few days and are intermittent in nature.
What are the three main types of volcanoes based on eruption frequency?
Active, Dormant, and Extinct volcanoes.
What is an active volcano? Give examples.
An active volcano has erupted in recorded history or is currently erupting and expected to erupt again (e.g., Mt. Vesuvius, Mauna Loa, Barren Island).
What is a dormant volcano? Give an example.
A dormant volcano is 'sleeping' but may erupt again in the future (e.g., Mauna Kea).
What is an extinct volcano? Give an example.
An extinct volcano has not erupted since remote geological times and is unlikely to erupt again (e.g., Mt. Kilimanjaro).
What are the main products of volcanic eruptions?
The main products are magma (lava), gases (steam, sulphur dioxide, etc.), and rock material (ash, pebbles, boulders).
What is the difference between magma and lava?
Magma is molten rock below the surface; when it reaches the surface, it is called lava.
Name some gases released during volcanic eruptions.
Steam, sulphur dioxide, hydrogen sulphide, hydrogen, and carbon dioxide.
What are igneous intrusions?
Igneous intrusions are bodies of igneous rock formed when magma solidifies below the Earth's surface, such as sills, dikes, batholiths, and laccoliths.
What is a sill?
A sill is a horizontal igneous intrusion formed when magma spreads between layers of rock.
What is a dike?
A dike is a vertical or steeply inclined igneous intrusion that cuts across rock layers.
What is a batholith?
A batholith is a large, deep-seated igneous intrusion formed from solidified magma.
