system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why was Krakatoa's eruption so much louder than other volcanic eruptions?

There have been numerous other volcanic explosions in Earth's history, and some which were hundreds of times more powerful than Krakatoa (Ex: The Toba Super-Eruption). Yet, Krakatoa's Eruption is considered one of the loudest events in Earth's history. Why is this?
gpt
One of the leading theories is because of Krakatoa proximity to water.

Krakatoa has been erupting for a while before it’s massive explosion, leading to the theory that would of the eruptions had actually plugged the caldera down to the magma chamber, allowing pressure to build.

The next step in the theory is that some part of the eruption/building pressure allowed a lot of sea water to rush into the magma chamber. This sea water instantly boiled when hitting the hot magma, creating gas, and a significant amount of pressure.

Like how pouring water into a pot of oil will send the oil everywhere (because the water sinks, hits the bottom of the pan, and instantly turns to gas bubbles sending the oil above it everywhere).

It’s theorized that this is what gave Krakatoa so much extra energy, several times more than say Mt St Helens’ eruption. Because of this flash boiling effect.