 Dense-rock equivalent calculations can also be used to measure the sizes of volcanic eruptions on other planetary bodies, such as Mars.However, the challenge to making these estimates is accurately estimating the density of the tephra deposit or of the dense rock, measuring the thickness of tephra, determining if the tephra is related to the eruption studied or to a nearby one, and estimating changes resulting from other geological processes that may be less understood than on Earth.Significant studies of the dense-rock equivalent erupted volumes of the Bronze-Age Minoan eruption in Santorini have provided data to archeologists to better understand the effect of the eruption on development of several civilizations including Ancient Greek and Ancient Egyptian cultures.