Chain of Pits on Arsia Mons
Chain of Pits on Arsia Mons
PSP_005414_1735  Science Theme: Tectonic Processes


The chain of pits visible in this image formed by collapse as the giant shield volcano, Arsia Mons, was pulled apart. While magma intruding into the volcano might have pushed the rocks aside, it is also possible that the collapse is caused by the volcano falling apart underneath its own weight.

The small pit in the middle of the chain was discovered by a team of scientists from the U.S. Geological Survey and Arizona State University using data from the THEMIS camera onboard the Mars Odyssey spacecraft during a search for possible cave entrances. They informally named this pit "Annie." (The subimage is 1500 x 1500; 2 MB).

A section of the HiRISE image over "Annie" has been specially processed to enhance the contrast in the shadowed areas. This shows that the pit is is largely filled with wind blown materials. Shadow measurements indicate that the floor is about 112 meters (367 feet) below the rim. This is an example of how the different NASA missions are working together to shed light on the darkest mysteries on Mars.

Written by: Laszlo P. Keszthelyi  (3 October 2007)

This is a stereo pair with ESP_011756_1735.
Acquisition date
22 September 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
252.2 km (156.7 miles)

Original image scale range
25.3 cm/pixel (with 1 x 1 binning) so objects ~76 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
34°, with the Sun about 56° above the horizon

Solar longitude
318.2°, Northern Winter

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  345.5°
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Black & white is 5 km across; enhanced color about 1 km
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All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:

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. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.