In the case of Hi-iaka, the northern and southern margins of the pateras have very similar shapes which appear to fit together. This may indicate that the crust has been pulled apart here and the resulting depression has subsequently been covered by dark lava flows. Furthermore, the two mountains bordering Hi-iaka Patera also appear to fit together. However, the similar shapes and heights of the pateras margins and mountains could be coincidental. Galileo scientists are currently investigating whether mountains and pateras are related to each other and what could cause the surface of Io to rift apart in such a manner.
North is to the top of the mosaic and the sun is illuminating the surface from the left.
The ASU Planetary Geology Group is under the direction of Dr. Ronald Greeley.