Dense-rock equivalent

Dense-rock equivalent

Dense-rock equivalent (DRE) is a way for scientists to figure out how much material a volcano releases during an eruption.

When a volcano erupts, it throws out things like pumice and volcanic ash, called tephra. This material is full of air spaces, so measuring it on the ground doesn’t tell us the whole story.

Scientists use dense-rock equivalent to find the real amount of magma that came out of the volcano. They compare how dense the tephra is on the ground to how dense the original rock would be without air spaces.

Dense-rock equivalent isn’t just for Earth—it can also help us study eruptions on other planets, like Mars. But it can be hard because we need to know the density of the materials and how thick the deposits are.

One famous example is the Bronze-Age Minoan eruption in Santorini. By studying the pumice and ash, researchers have learned more about how it affected ancient civilizations like the Ancient Greek and Ancient Egyptian cultures.