Underground short cut supplies the fuel

Most volcanoes get their magma directly from subduction zones, where crust plates disappear underneath each other and melt. Mount Paektu is located far away from the closest subduction zone, receiving its magma via an underground short cut.

CRUST PLATE SINKS

Under Japan, the oceananic crust is heading down into Earth’s mantle, where it melts, producing magma, which turns into Japan’s volcanoes, etc.

SINKING IS SLOWED DOWN

The crust “strands” at depths of 410660 km, as the density of the lower mantle is too high for the crust to sink any deeper. So, the crust plate levels out.

MAGMA FINDS SHORT CUT

About 600 km under Mount Paektu, the crust plate cracks. Moulten material underneath the crust plate is now able to escape, flowing up through the crack.

MAGMA CHAMBER FILLS UP

The material is light and warm enough to rise like a bubble towards the surface, supplying new fuel to the large magma chamber under Mount Paektu.