A quiet magma chamber can be a better bomb factory than a roaring lava fountain. Thick, silica rich melt creeps upward, yet that slow ascent hides an efficient pressure machine driven by gas and water. As magma rises, confining lithostatic pressure drops while dissolved volatiles obey Henry’s law and exsolve into bubbles. The melt stiffens into viscous, plug like rock that blocks vents, turning th...More