Volcanoes are sleeping giants

The world’s “sleeping giants” can wake up much quicker than thought, according to a new volcano model. Scientists believe the magma chambers—or reservoirs of molten rock—under dormant volcanoes are filled with sticky, viscous mush.

For a volcano to “wake up,” this mush needs to be thoroughly heated by fresh, hot magma rising up from the deep Earth.
According to current theory, it would take several hundred or perhaps a thousand years for the heat to distribute through the chamber and make the magma fluid enough to erupt.