flows. Basaltic (mafic) lava, with a lower silica content (~50%), is more fluid and may travel a long distance before congealing. Dissolved gases tend to make magma more fluid, and as they expand, provide the force that propels molten rock from the volcano. 2. The materials associated with a volcanic eruption include (1) lava flows (pahoehoe flows, which resemble twisted braids; and aa flows, consisting of rough, jagged blocks; both form from basaltic lavas); (2) gases (primarily water vapor);…
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