This high-resolution image shows the Olympus Mons caldera located 24 kilometers (15 miles) above the surrounding martian plains. The caldera is about 80 kilometers across with walls that are 2.4 to 2.8 kilometers deep. Calderas are produced when the roof of the magma chamber collapses due to removal of magma by voluminous eruptions or subterranean magma withdrawal.
This mosaic is constructed using pictures from the orbits 473S and 474S of Viking 1 near the end of its mission in 1980. As Viking 1 was near the lowest part of its orbit and moving very fast relative to the ground targets these pictures were shuttered using image motion compensation.
This image is Copyright © 1997 by A. Tayfun Oner. Any commercial/for-profit use of this image needs to be addressed to Calvin J. Hamilton.