Volcanic eruptions that look like single events are often the visible outcome of slow, complicated activity taking place deep underground. Beneath the surface, magma shifts position, changes chemically, and can sit for long stretches before finally erupting. To piece together what is happening below, scientists examine lava flows, rock textures, and minerals left behind at the surface. These clues help reveal the hidden magma systems that drive volcanic activity.

A recent study published in Geology shows that this same complexity exists on Mars. High resolution images of the landscape and mineral measurements collected from orbit indicate that some of the planet's youngest volcanic regions have a much more detailed history than previously assumed.…