Sticky magma traps gas to make volcanoes explode
While Hawaiian volcanoes leak fluid lava like honey, Guatemala's Fuego holds its breath until it bursts, launching ash clouds fifteen kilometers into the sky.
The difference between a gentle lava flow and a catastrophic explosion comes down to the amount of silica in the plumbing. At Guatemala's Fuego volcano, the magma contains up to sixty-five percent silica, creating a thick, pasty consistency about as viscous as cold peanut butter. This sticky sludge prevents gas bubbles from escaping to the surface, forcing them to remain trapped and pressurized as the magma rises. When the pressure finally overcomes the weight of the rock above, the gases expand with such violence that they shatter the magma into microscopic shards of volcanic ash.
There's more to this story — open the app to keep reading.