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Volcanism - Olympus Mons
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Volcanism - Olympus Mons

December 26, 2011
The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) obtained this spectacular wide-angle view of Olympus Mons on April 25, 1998. This volcano is three times taller than Mount Everest (26 km or 16 mi) and as wide as the entire Hawaiian Island chain. Despite its large size, the slopes are only a few degrees, making this a broad shield volcano. As such, it has long been inferred that this volcano consists mainly of basalt--the iron- and magnesium-rich volcanic rock common in places like Hawaii, Iceland, and the Earth's ocean floors.

When the picture was taken, Mars Global Surveyor was travelling from left to right. Although the camera looks straight down (towards the nadir) and cannot be pointed to the side, the wide angle camera has such a large field of view (it sees from horizon to horizon) that, in effect, it provides side-looking views. With this picture, it is easy to imagine that you are looking out a window at the surface of Mars from about 900 km (560 miles) up. The scene in the top half of the image is cloudy.

This color picture was made using MOC red wide angle image 26301 and blue wide angle image 26302. The green channel was synthesized by averaging the red and blue bands. The color is not the true color of Mars as it would appear to the human eye (the actual colors would be more pale and contrast more subdued). North is to the left, east is up.

Credits: Malin Space Science Systems/NASA