The first supervolcano on Mars of a size almost similar to the Yellowstone supervolcano in the United States has been discovered by European scientists.
The Martian supervolcano is named Siloe Patera. It now exists only as a massive crater measuring 40 kilometers by 30 kilometers (24 miles x 18 miles) and is thought to be some 1,750 meters (5,270 feet) deep.
Scientists noted Siloe Patera has two large craters, which could mean there could have been two separate massive eruptions of this supervolcano. On Earth, a supervolcano is defined as a volcano that can produce at least 1,000 cubic kilometers of volcanic materials in a single eruption. The Yellowstone supervolcano or caldera falls into this category.
Siloe Patera is found in the Arabia Terra, a large upland region in the north of Mars that is densely cratered and heavily eroded. Arabia Terra covers has an area of 4,500 kilometers (2,800 miles).
A 2013 study suggested a number of craters within Arabia Terra, including Siloe Patera, Eden Patera, Euphrates Patera, Ismenia Patera, Oxus Patera and Oxus Cavus represent calderas formed by massive eruptions of supervolcanoes during the Late Noachian to Early Hesperian age on Mars some three billion years ago.
New pictures of Siloe Patera were taken by the high-resolution stereo camera on the Mars Express probe of the European Space Agency (ESA). Analyses of these photos suggest Siloe Patera was caused not by a meteor but by a collapsing supervolcano.
ESA noted Siloe Patera features two depressions with steep-sided walls. This indicates the area might have collapsed when the magma pressure below the surface was released.
"Scientists believe that Siloe Patera and a number of similar features in the Arabia Terra area of Mars are calderas, the collapsed centers of volcanoes, but not just any volcanoes -- these are thought to be Martian super volcanoes," said ESA.
"A number of irregularly shaped craters have been detected in the Arabia Terra region that could represent a family of ancient supervolcano calderas.
"Siloe Patera is one such example. It is characterized by two depressions with steep-sided walls, collapse features and low topographic relief."