The flanks of Ascraeus Mons have a rumpled appearance caused by numerous low, rounded terrace-like structures arranged concentrically around the summit of the volcano. The terraces are spaced 30 to 50 km apart, have lengths up to 100 km, radial widths of 30 km, and heights of about 3 km. Individual terraces are not continuous around the volcano, but instead consist of arcuate segments that overlap with each other, forming an imbricate pattern. They are interpreted to be the surface expression of thrust faults that formed due to compression along the volcano's flanks. Flank terraces are also common on Olympus Mons and the other Tharsis shield volcanoes. The source of the compressive stresses is still debated. The flank terraces may be due to compressional failure of the volcano, flexing of the underlying lithosphere due to the volcano's massive weight, cycles of magma chamber inflation and deflation, or shallow gravitational slumping.