Tharsis - Location and Size

Location and Size

The Tharsis region can have several meanings depending on historical and scientific context. The name is commonly used in a broad sense to represent a continent-sized region of anomalously elevated terrain centered just south of the equator around longitude 265°E. Called the Tharsis bulge or Tharsis rise, this broad, elevated region dominates the western hemisphere of Mars and is the largest topographic feature on the planet, after the global dichotomy.

Tharsis has no formally defined boundaries, so precise dimensions for the region are difficult to give. In general, the bulge is about 5,000 km across and up to 7 km high (excluding the volcanoes, which have much higher elevations). It roughly extends from Amazonis Planitia (215°E) in the west to Chryse Planitia (300°E) in the east. The bulge is slightly elongated in the north-south direction, running from the northern flanks of Alba Patera (about 55°N) to the southern base of the Thaumasia highlands (about 43°S). Depending on how the region is defined, Tharsis covers 10–30 million km2, or up to 25% of Mars’ surface area.