Alba Mons Graben

Today's VIS image shows a single long depression north of Alba Mons. This feature is a graben and was formed by extension of the crust and faulting. When large amounts of pressure or tension are applied to rocks on timescales that are fast enough that the rock cannot respond by deforming, the rock breaks along faults. In the case of a graben, two parallel faults are formed by extension of the crust and the rock in between the faults drops downward into the space created by the extension. Alba Mons is surrounded by graben believed to be the result of extensional forces associated with the uplift of Alba Mons. The graben around Alba Mons can reach lengths of over 2072km (1287 miles) long.