Welcome to Olympus Mons!
Some day people are going to land on the planet Mars and begin the “up close and personal” exploration of its dry, dusty, frozen surface. They’ll have the benefit of years of Earth-based Mars exploration to help them to decide what to study first, as well as images and data from the fleet of spacecraft we’ve sent there since the mid-20th century.
One of the most fascinating places they visit will be Olympus Mons the tallest known volcano in the solar system. At a height of 27 kilometers above the average surface elevation on Mars, Olympus Mons is three times higher than Mount Everest here on Earth. If you placed it on Earth, it would cover an area roughly equivalent to all the islands in the state of Hawai’i. Or, if you are a skier, think of it this way: it would be a heck of a LONG run down from the top to the base! This volcano is so big that if you were standing at the edge of its caldera (the collapsed area at the very top of the volcano) the opposite edge would be 80 kilometers away!
What’s so interesting about this ancient shield volcano? For one thing, it is one of the most obvious features on the planet. Its rocks and structures will give explorers an unprecedented close-up look at the history of volcanic activity on the Red Planet. Some of the oldest lava flows on Olympus Mons date back 115 million years! On the other hand, some rocks on the mountain’s flanks are only 2 million years old, which means that volcanism was occurring relatively recently (in geologic terms).
We can also compare it to shield volcanoes that we know about here on Earth such as Mauna Kea or Mauna Loa in Hawai’i. We know how they formed over millions of years by continuous flows of very fluid lavas, each flow overlying the previous one. Seeing a similar structure on another planet tells us that it formed in a very similar manner to Earth’s shield volcanoes.
We don’t see a lot of evidence for changes on the Mars surface such as glowing lava flows or steaming vents that would be considered “tell-tales” of geologic activity going on today. It’s not completely clear that Mars will have volcanic eruptions in the future, although it’s still possible that unknown hotspots deep inside the planet could still send lava flows out to the surface.
Scientists continue to study the ancient lava flows of Mars’s past to find clues to its evolution and future. Those places on Mars affected by volcanism are snapshots of a time when things were very different from what they are today. Olympus Mons and its sister volcanoes Ascraeus Mons, Pavonis Mons and Alba Patera formed when Mars was very geologically active. The next big questions to answer are “What caused the Martian volcanoes to stop flowing and will they ever flow again?” Only time and continued exploration of Mars will tell.
Want more information about Mars and its volcanoes? Go to the Geology of Mars page, NASA’s Major Martian Volcanoes page or the Wikipedia page for Olympus Mons to visit Olympus Mons and read more about this fascinating place.