ABSTRACTPhysical models have been widely used to study geological structures for more than one hundred years. The greatest benefi t of physical models is that with proper scal-ing of model dimensions and materials, researchers can directly observe structural or tectonic processes that take millions of years to occur naturally. Despite this ben-efi t, however, use of physical models is not widespread because their construction and analysis is commonly labor-intensive work that yields largely qualitative information on structural geometry and limited quantitative information on displacement and strain. This paper describes how close-range photogram-metry can be used to obtain quantitative information on the geometry, displacement, and strain patterns in an evolving physical model. The technique is an inexpensive, high-resolution, noninvasive, and effi cient method that uses standard commercial software and a digital camera to determine the x , y , z posi-tions of high-contrast markers placed on the model surface. The model geometry at any given time is defi ned by the positions of all the markers, whereas strain and displace-ment are obtained by comparing, or track-ing, the positions of the markers at different times during an experiment. We present as an example application of the technique, an analysis of scaled physical models of mono-clines that form above basement-involved reverse faults with differing displacement distributions. Using close-range photogram-metry, we are able to link fault displacement and lateral propagation history to unique, evolving, three-dimensional (3-D) geometries and deformation patterns that are unlikely to be revealed by other analysis techniques.Keywords: physical model, monocline, base-ment uplift, photogrammetry, strain.INTRODUCTION