Answer
Picture A shows a volcanic eruption that is explosive and violent, while Picture B shows a less violent eruption.
If the volcano erupted violently, it has a high viscosity magma, such as rhyolitic magma.
If the volcano erupted less violently, it has a low viscosity magma, such as basaltic magma.
A magma with high viscosity is thick and sticky, while a magma with low viscosity is runny and fluid.
The viscosity of magma affects the type of volcanic eruption because high viscosity magma traps gas bubbles, causing pressure to build up until it explodes violently. Low viscosity magma allows gas bubbles to escape more easily, resulting in a less explosive eruption.