Magma chamber pressurization, volatile exsolution, and eruption style
Volatile Content (H₂O %)3.5%
Magma Supply Rate1.5
Conduit Radius (m)20 m
Magma Viscosity10⁵ Pa·s
Eruption Style
Chamber Pressure
—
Volatile Saturation
—
Eruption Flux (m³/s)
—
VEI: 4 — Large Plinian
Plume height: —
Eruption rate: —
Eruption style is controlled by magma composition (silica content → viscosity) and volatile content. Low-viscosity basaltic magmas (Hawaii) allow gases to escape gently. High-viscosity rhyolitic magmas trap volatiles until catastrophic pressure release (Plinian). The Volcanic Explosivity Index (VEI) is logarithmic — VEI 8 events (supervolcanoes like Toba, 74 kya) eject >1000 km³.