How does the viscosity (thickness) of lava affect the shape of a volcano?
2007-03-07 10:06:03 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Geography
The viscosity of the magma determines both the type of volcano which forms and the activity associated with that type of volcano. Magma viscosity is directly related to silica (SiO2) content (approximately 50-70 %) and temperature.
Viscosity is the principal property which determines the form of erupted lava. It is mainly dependent on chemical composition, temperature, gas content, and the amount of crystals in the magma. Liquid lava with basaltic composition (such as in Hawaii)—relatively low in silicon and aluminum and high in iron, magnesium, and calcium—has higher fluidity (lower viscosity) compared with lava of rhyolitic or dacitic composition (such as at Mount St. Helens, Washington), with higher abundance of silicon and aluminum but lower amounts of iron, magnesium, and calcium. High temperature and gas content of the liquid lava, combined with low crystal abundance, also contribute to increased lava fluidity. Measured maximum temperatures of basaltic lava (1150–1200°C; 2100–2190°F) are higher than those for andesitic and more silicic lavas (720–850°C; 1330–1560°F). Very fluid basaltic lavas can flow great distances, tens to hundreds of kilometers, from the eruptive vents; in contrast, more silicic lavas travel much shorter distances, forming stubby flows or piling up around the vent to form lava domes.
2007-03-11 08:44:20 · answer #1 · answered by Anonymous · 3⤊ 2⤋
Viscosity Of Lava
2016-11-12 06:32:39 · answer #2 · answered by Anonymous · 0⤊ 0⤋
The thicker lava like the volcanoes in Hawaii produce a rounder or domed shape top. I know that for sure.
By reasoning it out, thinner faster flowing lavs would run done the slope faster creating a volcano steep sides.
2007-03-07 12:38:15 · answer #3 · answered by Lost in PA 2 · 0⤊ 0⤋
high viscosity =low velosity =thick
low viscosity=high velosity =thin
shield volcano is flatter and more spread out because it has lower viscosity
Sinder Cone volcano has high velosity lava because it is pointer and taller because it does not spread out as much
2007-03-07 13:42:48 · answer #4 · answered by Jen palla【ツ】 3 · 0⤊ 0⤋
the thicker the lava the slower it moves and this is the simple answer the thiner the lava so it flows more before it turns back to rock(cools down)
2007-03-07 10:18:14 · answer #5 · answered by travis p 2 · 0⤊ 0⤋