Lava with a higher content of _______ has higher viscosity. If a large explosion causes the magma chamber below a volcano to empty, the volcano can collapse and form a/an _______. Shield volcanoes can form when less _______ lava flows quickly away from a vent. Respond to the following based on your reading. Briefly describe what causes a volcanic eruption to be explosive.
4. Explosions from composite volcanoes occur as a result of gas buildup within them. Shield volcanoes also may erupt explosively if water accumulates inside their vents.
