Tharsis Tholis towers 8 km above the surrounding terrain. Its base stretches 155 x 125 km and its caldera is about 32 x 34 km. The caldera floor has subsided by as much as 2.7 km. The image has a ground resolution of approximately 14 m per pixel and was derived from the nadir channel of the High Resolution Stereo Camera on Mars Express, which provides the highest detail of all the channels.