>In general, volcanoes are classified as silicic or mafic. The silicic ones contain more gas and tend to erupt explosively; the mafic ones, more lava floes.
A few geology papers were part of my engineering study way back when - we were taught 3 types: basalt, andesite, and rhyolite in order of explosiveness. It might have been NZ biased.
I presume basalt is in the mafic group, and the other two are silicic?
Yes, you are correct. The difference between andesitic and rhyolitic classifications is based on silica content.
Andesitic is the midrange member of the continuum from rhyolitic (silicic, explosive) and basaltic (mafic/ultramafic, more lava and oozing) end members.
A few geology papers were part of my engineering study way back when - we were taught 3 types: basalt, andesite, and rhyolite in order of explosiveness. It might have been NZ biased.
I presume basalt is in the mafic group, and the other two are silicic?