Eastern Scarp of Olympus Mons
This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express spacecraft, shows the eastern scarp of the Olympus Mons volcano on Mars.
The scarp is up to six kilometres high in places. The surface of the summit plateau's eastern flank shows lava flows that are several kilometres long and a few hundred metres wide. Age determinations show that they are up to 200 million years old, in some places even older, indicating episodic geological activity.
The lowland plains, seen here in the eastern part of the image (bottom), typically have a smooth surface. Several channel-like features are visible which form a broad network composed of intersecting and 'anastomosing'* channels that are several kilometres long and up to 40 metres deep. (*Anastomising means branching extensively and crossing over one another.)
Several incisions suggest a tectonic control, others show streamlined islands and terraced walls suggesting outflow activity.
Age determinations show that the network-bearing area was geologically active as recent as 30 million years ago.
Between the edge of the lowland plains and the bottom of the volcano slope, there are 'wrinkle ridges' which are interpreted as the result of compressional deformation. In some places, wrinkle ridges border the arch-like terraces at the foot of the volcano slope.
This colour image has been derived from the three HRSC-colour channels and the nadir channel.