Arches National Park contains the greatest density of arches in the world. Photogrammetry was used to model arches, including Landscape Arch, considered by the National Park Service to be the largest natural rock span in North America. These models were used to study natural vibration of the structures. This collaborative effort with the University of Utah seeks to better understand how arches vibrate, and whether vibrational characteristics can be used to understand changing internal strength or damage that might precede collapse.