This image shows an impact crater about 3-kilometer (1.8 miles) wide in a region that has been flooded by lava.
The lava has overtopped the rim in at least two areas, to the southwest and northwest, and created a pond of lava on the crater floor. Where it flowed down the steep crater slope it carved gullies . There are similar gullies on steep crater slopes on the Moon, but probably carved by impact melt rather than lava. Dark streaks seen elsewhere on the crater slopes are from dust avalanches.
On the plains outside the crater there are distinctive landforms that form from lava inflation, where molten lava is injected under a solid crust to raise the surface. Only lava behaves in this manner, not mud or other fluids that might have been present on Mars.
Written by: Alfred McEwen (audio by Tre Gibbs) (14 November 2012)
This is a stereo pair with ESP_037749_1785 .
More info and image formats at http://hirise.lpl.arizona.edu/ESP_028321_1785
Image: NASA/JPL/University of Arizona