Ackermann et al. (1975) described the subsurface structure of Meteor Crater and identified a fractured rock zone extending to about 1 km deep. The depth of the fractured/damage zone can be used to extract information about the impact cratering process. We impacted rock samples (San Marcos gabbro) in the laboratory and imaged the damage structure using both dicing and tomography methods. We propose a simple model to describe the damage zone depth based on the laboratory measurements. The model agrees well with other methods for the estimation of the projectile size of Meteor Crater and it may be used for estimates of damage around craters of other planets and moons. ¿ 2001 American Geophysical Union