Polar Cliffs and Falling Blocks
Polar Cliffs and Falling Blocks
ESP_027451_2635  Science Theme: Polar Geology
There is an ice sheet at the North Pole of Mars that is a few miles thick at its center. At some places (like in this image) it ends in steep cliffs that can be about 800 meters (2,600 feet) high.

The slopes of these cliffs are almost vertical which causes slab-like blocks of ice to break off and crash down to the surrounding plains. Dense networks of cracks cover these icy cliff faces making it easier for these blocks to break free. We've seen new debris at the base of many of these cliffs appearing between successive HiRISE images, so we regularly monitor sites like this to check for new blocks that have fallen. Understanding how these cliffs are formed helps us understand the climatic record stored in the ice sheet itself.

Have any new blockfalls occurred here? Try and compare this image with another taken almost exactly one Martian year ago and check for yourself!

Written by: Shane Byrne  (11 July 2012)
Acquisition date
04 June 2012

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
320.5 km (199.2 miles)

Original image scale range
32.1 cm/pixel (with 1 x 1 binning) so objects ~96 cm across are resolved

Map projected scale
25 cm/pixel

Map projection

Emission angle

Phase angle

Solar incidence angle
63°, with the Sun about 27° above the horizon

Solar longitude
120.0°, Northern Summer

For non-map projected images
North azimuth:  115°
Sub-solar azimuth:  320.8°
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   (550MB)

IRB color
map-projected   (312MB)

Black and white
map-projected  (269MB)
non-map           (209MB)

IRB color
map projected  (87MB)
non-map           (192MB)

Merged IRB
map projected  (139MB)

Merged RGB
map-projected  (134MB)

RGB color
non map           (194MB)
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.