Main Page1. Viscosity - resistance to flow determines how explosively volcanoes erupt
fluid = flows easily like water
viscous = thick and pasty like honey
a. Temperature - hotter magmas are more fluid
b. Composition - mafic magmas are more fluid; therefore, mafic basalt lava flows more easily than felsic rhyolite lava
c. Gases - escaping gases provide force to propel lava from vent; rhyolite magmas contain more dissolved gases than do basalt magmas
2. Explosivity
|
Composition |
Temperature |
Viscosity |
Gases |
Explosivity |
|
mafic basalt |
hotter |
lower |
less |
LESS |
|
felsic rhyolite |
cooler |
higher |
more |
MORE |
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