This image was suggested by Ehsan Sanaei's high school astronomy club in Yazd, Iran.

They noticed a set of craters around the rim of Tyrrhena Patera. Tyrrhena Patera is a volcano in the southern highlands with shallow slopes, and only 2 kilometers (1.2 miles) of vertical relief. The craters are aligned and are known as pit crater chains. These are common in volcanic regions on Mars.

They are not formed by a meteorite impact, but by collapse into some void space underground. Because the pit crater chains and concentric fractures are generally aligned, these are most likely due to extension in the region, where parts of the Martian crust pull apart during growth of the volcano or emplacement of dikes.

Another way pit crater chains can occur is when lava tubes partially collapse forming chains of holes along the roof of the lava tube. A third possibility is that these may be associated with collapse of the magma chamber.

For information about NASA and agency programs on the Web, visit: http://www.nasa.gov. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona. The image data were processed using the U.S. Geological Survey’s ISIS3 software.