Context image

The linear features in this VIS image are tectonic graben. These graben are called Sirenum Fossae. 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. Several graben are visible in this THEMIS VIS image, trending from east to west. Because the faults defining the graben are formed parallel to the direction of the applied stress, we know that extensional forces were pulling the crust apart in the north/south direction. The majority of the stresses that created Sirenum Fossae are aligned in the in a north-northwest to south-southeast direction. The Sirenum Fossae graben are 2735km (1700 miles) long.

Orbit Number: 91772 Latitude: -27.9695 Longitude: 216.058 Instrument: VIS Captured: 2022-08-22 19:21

Please see the THEMIS Data Citation Note for details on crediting THEMIS images.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Science Mission Directorate, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.