MOUNT OLYMPUS (MARS): CHARACTERISTICS, WHAT WOULD HAPPEN IF YOU WERE ON EARTH? - ARTE - 2025

The Mount Olympus, officially designated by the International Astronomical Union as Olympus Mons is the largest volcano is known so far in the Solar System. It is found on Mars, on the Tharsis volcanic plateau near the equator.

This colossal geological structure is about 600 kilometers wide and 24 kilometers high, dwarfing the largest terrestrial volcano, Mauna Loa in Hawaii. In fact, the Hawaiian island chain fits comfortably on Mount Olympus.

Figure 1. Artist's representation of the sunset over Mount Olympus on Mars. Source: Kevin Gill via Flickr.

Astronomers in the 19th century had already observed a bright spot on the Martian surface, because Mount Olympus sometimes strongly reflects sunlight - albedo -.

The great Italian astronomer Schiaparelli (1835-1910), who for a long time explored the Martian surface with the telescope, called this region Nix Olympica or Snows of Olympus, although he surely did not imagine that it was a huge mountain.

Thanks to space probes like the Mariner, launched in the early 1970s, the true nature of these patches was discovered: they were gigantic volcanoes. Thus, from then on the Nix Olympica became the Olympus Mons, just like the residence of the ancient Greek gods, covered in a brilliant white glow.

Mount Olympus Features

Volcanism is a frequent geological process on rocky planets like Earth and Mars. Mount Olympus, the largest of the volcanoes in Tharsis and in the Solar System, is quite young, formed during the Amazonian period of Mars, an era characterized by intense volcanism.

Other important shaping factors of the Martian surface are meteorites, which have peppered large areas with impact craters. This has made it possible to establish three geological periods according to the abundance of these craters: Noeic, Hesperic and Amazonian.

The Amazonian period is the most recent, spanning from 1800 million years to the present. It is the rarest period in terms of impact craters.

It is followed in antiquity by the Hesperian and finally the Noeic, the oldest and most abundant in craters.

This allows us to estimate the age of Martian volcanoes by the number of craters on their slopes. And since there are few on Mount Olympus, it suggests that it is a very young volcano in geological terms: about 100 million years old or so. By then dinosaurs still populated the Earth and were far from extinct.

Coordinates and extent

Mount Olympus is in the western hemisphere of Mars, near the equator, at the coordinates 18.3 ° N and 227 ° E of the red planet.

It rises to an average height of 22 km, assuming that it is located in a depression of the ground about 2 km deep. This is approximately three times the height of Everest in the Himalayas, the highest mountain on Earth.

It is a shield-type volcano, whose shape is that of a low dome, which differentiates it from volcanoes with steep slopes and a cone shape.

Its extension is about 600 km in diameter at its base. Thus, although much higher than any land structure, the slope is quite gentle. Its volume is estimated to be about 100 times that of Mauna Loa, the largest shield-type volcano on Earth.

The large size of Mount Olympus is explained by the absence of tectonic plates on Mars. For this reason, the volcano remained fixed on an extremely hot place - the hot spot -, which allowed the flow of enormous streams of lava for long periods.

The images show the slopes of the volcano covered in countless layers of overlapping lava, called coladas, which have been solidifying and increasing the size of the structure.

Pressure, temperature and characteristics of the top of Mount Olympus

A hypothetical traveler who manages to reach the top of Mount Olympus would find that the atmospheric pressure of the thin Martian atmosphere is only 7% of the value at the surface, and would also find very low temperatures: less than 100 ° C below zero.

The gravity is quite less than the terrestrial one, and since the slope is very soft, between 2 and 5º, this would make the journey to the top a very long walk.

But it would be rewarded with a wonderful night sky, as the summit towers far above the dust storms that hit the plain and the mists of the lower Martian atmosphere.

At the top is also the volcano's caldera, about 2-3 km deep and 25 km wide, caused by the collapse of the magmatic chamber during eruptions.

Figure 2. South view of the caldera of Mount Olympus. Source: Wikimedia Commons. ESA / DLR / FU Berlin (G. Neukum).

The probes have found evidence of lava flows as recent as about 2 million years, suggesting that the volcano may be dormant and will eventually erupt again.

The landscape around Mount Olympus

The Tharsis plateau or bulge is home to volcanoes other than Mount Olympus. Among them are the Arsia, Pavonis and Ascraeus mountains, also of the shield type and smaller in size, but with a greater slope.

Their peaks also rise above the thin Martian mists and also dwarf the terrestrial volcanoes, since they are at least 10 times greater.

As we said, Mount Olympus is in a depression in the terrain created by the pressure of the mountain on the crust. It is surrounded by an area called aureole, full of deep ravines as evidence of glacial activity that occurred in ancient times.

Beyond Tharsis there is a group of canyons some 5000 km long, called the Mariner Valley. They were discovered by the probe of that name in 1971. There the Martian crust breaks, forming canyons more than 80 km wide and valleys so deep that they reach up to 8 km.

Tharsis is not the only volcanic region on Mars. Elysium Planitia is the second volcanic zone, located on a plain crossed by the Martian equator.

In short, they are landscapes so imposing that they far surpass terrestrial dimensions. Which leads us to ask how it is possible that such structures are generated.

What if you were on Earth?

Despite the fact that Mars is smaller than Earth, it is home to the largest volcanoes in the Solar System. The absence of plate tectonics on the red planet is a decisive factor.

When there is no plate tectonics, the volcano remains fixed over the hot spot, an area of ​​high volcanic activity. This results in layers of lava accumulating.

On the other hand, on Earth, the crust experiences movements that do not allow volcanoes to grow unlimitedly. Rather, they spread out here, forming volcanic island chains, such as the Hawaiian Islands.

Furthermore, scientists agree that the eruption rate on Mars is much higher than on terrestrial volcanoes, due to the lower gravity.

These two factors: absence of tectonism and less gravity, make possible the emergence on Mars of these gigantic and amazing structures.

References

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3. Taylor, N. Olympus Mons: Giant Mountain of Mars. Recovered from: space.com.
4. Martian volcanoes. Recovered from: solarviews.com.
5. Wikipedia. Mount Olympus (Mars). Recovered from: es.wikipedia.org.
6. Wikipedia. Volcanism on Mars. Recovered from: es.wikipedia.org.