Some of these probably formed by meteor impact, but many show no ejecta pattern characteristic of meteor impact. Other craters may have formed by explosive volcanism. Evidence for explosive volcanism on Mars has been very difficult to identify from previous Mars spacecraft images. This and other MOC data are being examined closely to better understand the nature and origin of volcanic features on Mars. Red channel is MOC red wide angle image 40301, the blue channel is MOC blue wide angle image 40302, and the green channel is synthesized by averaging the red and blue bands.
North is up, illumination is from the lower right.
Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission.