Fig. 4

Ridge topographic profiles and cross-sectional areas measured from the CTX stereo DEM shown in Fig. 2. a This section of the FSD consists of outer ridge, smooth, and inner ridge units which rest on a regional slope of 0.1^°. We, in agreement with prior work, interpret the outer ridges as terminal moraines (b) which are much larger than the interior ridges (c). The red lines in (b) and (c) indicate that ridges at Arsia are smaller and more closely spaced than at Pavonis (black, magenta, and blue lines). d The increase in cross-sectional area (y-axis) with ridge width (x-axis) generally follows the trend given by an isosceles triangle with flank slopes of 3^° (dashed line) although the smaller, inner ridges tend to have steeper slopes, but well below the angle of repose