Dense-rock equivalent

Dense-rock equivalent (DRE) is a volcanologic calculation used to estimate the volume of a volcanic eruption. When a volcano erupts, it can release a lot of material, such as pumice and volcanic ash, called tephra. Scientists often measure how much tephra is on the ground after an eruption, but this doesn't tell the whole story because the material contains lots of air spaces.

To find the real volume of magma that came out of the volcano, scientists use dense-rock equivalent. They compare how dense the tephra is on the ground to how dense the original rock would be without any air spaces. This helps them figure out the original size of the eruption.

Dense-rock equivalent isn't just for Earth—it can also be used to study eruptions on other planets, like Mars. But it can be tricky 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 from this eruption, researchers have learned more about how it affected ancient civilizations like the Ancient Greek and Ancient Egyptian cultures.