Located northeast of Elysium Mons (slide #14), Hecates Tholus is comparable in size to Elysium Mons and is close to the crest of the regional crustal uplift. Several collapse events are recorded within the caldera complex and the caldera rim has been breached by at least two sinuous channels. The flanks of the volcano have a rather dense cover of craters, indicative of a considerable age for the volcano, except in a region to the west of the summit caldera (see arrow). The sparsity of craters in this region has been interpreted to be the result of burial by pyroclastic materials (ash) erupted explosively from the summit area.
33 N, 210 W;
Viking Orbiter frame 651A19, shading corrected version.