GEOLOGY

Detailed explanation-1: -Different magma types behave differently as lava flows, depending on their temperature, viscosity, and gas content. Pahoehoe Flows-Basaltic lava flows with low viscosity start to cool when exposed to the low temperature of the atmosphere.

Detailed explanation-2: -Differences in a magma’s viscosity will determine the shape a volcano takes. High-silica (basalt) magma has a much lower viscosity. It flows much easier and over longer distances. As low-silica magma cools, it hardens to rock, adding a new thin layer of rock to the volcano.

Detailed explanation-3: -Quiet eruptions produce two different kinds of lava: chunks called aa, or smooth coils called pahoehoe. Mt. Kilauea in Hawaii erupts quietly, producing low-viscosity lava flows. High-silica magma produces explosive eruptions.

Detailed explanation-4: -Because of basalt’s low silica content, it has a low viscosity (resistance to flow). Therefore, basaltic lava can flow quickly and easily move >20 km from a vent. The low viscosity typically allows volcanic gases to escape without generating enormous eruption columns.

Detailed explanation-5: -So, mafic lavas are hot, low in silica and volatiles, and have relatively low viscosity. They flow easily outward from the vent (where it comes out of the ground), and may travel great distances before completely solidifying. Felsic lavas are not as hot, high in silica and volatiles, and have a high viscosity.