USGS Frequently Asked Questions
|
Question:
What is a volcano?
|
Answer: Volcanoes are mountains, but they are very different from other mountains;
they are not formed by folding and
crumpling or by uplift and erosion.
Instead, volcanoes are built by the accumulation of their own eruptive products
--
lava,
bombs (crusted over lava blobs),
ashflows,
and
tephra (airborne ash and dust).
A volcano is most
commonly a conical hill or mountain built around a vent that
connects with reservoirs of molten rock below the
surface of the Earth.
The term volcano also refers to the opening or vent through
which the molten rock and
associated gases are expelled.
-- From:
Tilling, 1985, Volcanoes: USGS General Interest Publication.
|
Source of this FAQ:
http://vulcan.wr.usgs.gov/LivingWith/VolcanicFacts/misc_volcanic_facts.html#strato_volcano
Return to list
|
U.S. Department of the Interior |
U.S. Geological Survey