Cluster of Secondary Impact Craters
Cluster of Secondary Impact Craters
ESP_017244_2050  Science Theme: Volcanic Processes
This observation was taken to see if the cluster of pits were formed by the interaction of hot lava with water. Such pits and cones have been found in this region, most likely because there was significant ice in the ground when a large lava flow inundated the area.

However, in this case, HiRISE reveals that the circular features are a mass of impact craters (note that the word “crater” is used by geologists for holes formed by volcanic, impact, and other geologic processes). The tight clustering of these craters is unusual. The most likely explanation is that they were formed by a clump of material thrown out from a larger impact crater nearby. As such, they are called “secondary” craters with the larger source crater called a “primary”. This HiRISE image covers too small an area to identify the primary.

Written by: Lazlo Kestay  (21 April 2010)
Acquisition date
01 April 2010

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
288.6 km (179.4 miles)

Original image scale range
58.3 cm/pixel (with 2 x 2 binning) so objects ~175 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
41°, with the Sun about 49° above the horizon

Solar longitude
71.6°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  14.8°
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

Black and white
map-projected   (565MB)

IRB color
map-projected   (261MB)

Black and white
map-projected  (291MB)
non-map           (292MB)

IRB color
map projected  (145MB)
non-map           (246MB)

Merged IRB
map projected  (588MB)

Merged RGB
map-projected  (545MB)

RGB color
non map           (231MB)
B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

IRB: infrared-red-blue
RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

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.