The volcano consists of two, roughly concentric components: 1) an oval-shaped central body with approximate dimensions of by across surrounded by 2) a vast, nearly level apron of lava flows that extends an additional or so outward. The central body is the main topographic edifice of the volcano, marked by pronounced break in slope at the inner boundary of the apron. Extending east and west from the central edifice are two broad fan-shaped lobes (or shoulders), which give the volcano its elongation in the east-west direction. The central edifice has the steepest slopes on the volcano, although they are still only 1°. The crest and upper flanks of the edifice are cut by a partial ring of graben that are part of the Alba and Tantalus Fossae fracture system. Inside the ring of graben is an annulus of very low and in places reversed slopes that forms a plateau on top of which lies a central dome across capped by a nested caldera complex. Thus, the central edifice of Alba Mons resembles a partially collapsed shield volcano with a smaller, summit dome sitting on top (pictured right). The summit dome has a distinct tilt to the east.