MESSENGER confirmed that the contraction of Mercury resulted in a global array of lobate scarps, tectonic landforms that are the surface expression of thrust faults. Enterprise Rupes is the Goliath of lobate scarps on Mercury (top, white arrows). At about 1000 km long, comparable in length to Earth’s San Andreas fault, and with over 3 km of relief it is the largest lobate scarp on Mercury. Images obtained after MESSENGER’s altitude was lowered during the last phase of its mission have revealed a population of small fault scarps (bottom, white arrows) that can be more than an order of magnitude smaller in size than their larger counterparts. These small scarps are less than 10 km in length and have only tens of meters of relief. They are comparable in size and morphology to small fault scarps imaged on the Moon by the Lunar Reconnaissance Orbiter.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/Smithsonian Institution