A Strange Squishy Impact Crater
A Strange Squishy Impact Crater
ESP_018023_2145  Science Theme: Impact Processes
This crater is one of a small group of highly unusual craters found in the Northern lowlands near the Elysium Mons volcano. The ground seems to have been soft and “squishy” when it was hit by the meteorite. This in itself is not that unusual for Mars.

In many locations the material thrown out from impact craters appears to have flowed like mud. It is generally agreed that this is because there was a lot of ice in the ground and this ice was melted by the energy of the impact, producing a large amount of mud.

However, in this area, the ejecta seems to have largely vaporized. More puzzling is the way that the crater appears to have collapsed into itself. It appears that there are some hard layers near the surface and then soft material that melts or vaporizes underneath. Indeed, HiRISE reveals a lot of rocky boulders associated with the hard layers.

One possibility is that this region had a thick layer of relatively pure water ice protected by a thin, hard, layer of boulders. So the impact punched through the hard coating, and both the ejecta and the center of the crater essentially evaporated into the atmosphere. This is plausible since this region is thought to be covered by mudflows running off of the Elysium Mons volcano.

Written by: Lazlo Kestay  (30 June 2010)

This is a stereo pair with ESP_017601_2145.
Acquisition date
31 May 2010

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
295.9 km (183.9 miles)

Original image scale range
59.6 cm/pixel (with 2 x 2 binning) so objects ~179 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
43°, with the Sun about 47° above the horizon

Solar longitude
98.3°, Northern Summer

For non-map projected images
North azimuth:  96°
Sub-solar azimuth:  6.7°
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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.