Image 4 of 6. These images, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express, are of the Acheron Fossae region, an area of intensive tectonic (continental ‘plate’) activity in the past.

The images show traces of enormous stress and corresponding strain in the crust of the Red Planet. The HRSC was pointed twice at this interesting geological feature in the Acheron Fossae mountain range, during orbits 37 and 143.

The feature is situated at approximately 35º-40º North and 220º-230º East, about 1000 kilometres north of the large Olympus Mons volcano.

For practical use on the internet, the images have been reduced in their resolution – the data originally obtained from orbit at an altitude of 765 kilometres (orbit 37) and 1240 kilometres (orbit 143) have a resolution of 30 metres and 50 metres per pixel respectively.

Images 4-6, with the large crater, 55 kilometres in diameter, were taken about 250 kilometres west of images 1-3.

They show how the rifting crosses the older impact crater with at least three alternating horsts and grabens.