When it falls back to the ground, this material makes circular white and yellow deposits around the vent. The white deposits are thought to be composed mostly of sulfur dioxide that left the volcanic vent as a vapor and condensed into a frost as the gases expanded into the near-vacuum of Io's atmosphere. Interestingly, red plume material has only been deposited to the northwest. This might be the result of small pockets of boiling sulfur that produce droplets of red sulfur blown outward by the main plume. Most of the other, more subtle color variations around Zamama are likely to be the result of different lighting conditions that existed when the two images were taken.
North is to the top of the pictures.
The images are centered at 17.4 degrees north latitude and 173 degrees west longitude. The Sun illuminates the surface from the right. The Sun illuminates the surface from almost directly behind the spacecraft. The ASU Planetary Geology Group is under the direction of Dr. Ronald Greeley.