I'd like to know about the construction of volcanoes???
Casey
Hi Casey,
Volcanoes are constructed mainly of two materials: lava and ash. Both of
these volcanic products come in many different variations and different
volcanoes have different proportions of them. For example, shield
volcanoes (such as those in Hawai'i and the Galapagos) are probably >95%
lava and only ~5% ash (in the form of cinder). Furthermore, the basaltic
lava that makes up shield volcanoes is very fluid and cannot be piled up
into steep mounds. This is why shield volcanoes have very gradual slopes.
Another kind of volcano is called either a strato-volcano or
composite-volcano. Mt. St. Helens, Pinatubo, and Fuji are all strato
volcanoes. Strato-volcanoes have a higher proportion of ash, and perhaps
are up to 50-50 lava and ash. Ash is loose and can be piled up to slopes
up to 30 degrees. Additionally, these strate-volcanoes erupt much more
viscous lava than basalt, and this highly viscous lava doesn't flow very
well (the Mt. St. Helens lava dome is an example of this lava). Because
of theis combination of viscous lava and ash, strato volcanoes are much
steeper than shield volcanoes.
Hopefully this starts to answer your questions. I apologize for the delay
in answering.
Sincerely,
Scott Rowland
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