Mars Express Image: Olympus Mons caldera in perspective

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This perspective view, taken by the High Resolution Stereo Camera (HRSC)
on board ESA’s Mars Express spacecraft, shows the complex caldera of
Olympus Mons on Mars, the highest volcano in our Solar System.

Olympus Mons has an average elevation of 22 kilometres and the caldera,
or summit crater, has a depth of about 3 kilometres. The data was
retrieved during orbit 143 of Mars Express on 24 February 2004. The view
is looking north.

The curved striations on the left and foreground, in the southern part
of the caldera, are tectonic faults. After lava production has ceased
the caldera collapsed over the emptied magma chamber. Through the
collapse the surface suffers from extension and so extensional fractures
are formed.

The level plain inside the crater on which these fractures can be
observed represents the oldest caldera collapse. Later lava production
caused new caldera collapses at different locations (the other circular
depressions). They have partly destroyed the circular fracture pattern
of the oldest one.

This perspective view of the caldera was calculated from the digital
elevation model derived from the stereo channels and combined with the
nadir and colour channels of the HRSC.