Tempe Fossae

Today's VIS image is shows a small portion of Tempe Fossae. The linear features are tectonic graben. Graben are 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. This image is located in a region of Tempe Terra that is complexly fractured, with multiple crossing directions. The variety in trends indicates several different periods of tectonic activity. The complete fossae system in almost 2000 km (1242 miles) long.