Silica content controls viscosity — from gentle lava flows to catastrophic Plinian columns
Low viscosity basaltic magma allows dissolved gases to escape gently. Produces fluid lava flows that travel great distances. Hawaiian eruptions can sustain lava fountains for months.
VEI 0–2. Kilauea (ongoing), Stromboli (Italy). Lava flows at 10–50 km/h. SO₂ and CO₂ released continuously. Lahar risk minimal.