Since the advent of affordable consumer-grade cameras over a century ago, photographic images
have been the standard medium for capturing and visualizing outcrop-scale geological features.
Despite the ubiquity of raster image data capture in routine fieldwork, the development of
close-range 3D remote-sensing techniques has led to a paradigm shift in the representation and
analysis of rock exposures from two- to three-dimensional forms. The use of geological 3D
surface reconstructions in routine fieldwork has, however, been limited by the portability,
associated learning curve, and/or expense of tools required for data capture, visualization, and
analysis. Smartphones are rapidly becoming a viable alternative to conventional 3D close-range
remote-sensing data capture and visualization platforms, providing a catalyst for the general
uptake of 3D outcrop technologies by the geological community, which were up until relatively
recently the purview of a relatively small number of geospatial specialists. Indeed, the
continuous improvement of smartphone cameras, coupled with their integration with global
navigation satellite system (GNSS) and inertial sensors provides 3D reconstructions with
comparable accuracy to survey-grade systems. These developments have already led many field
geologists to replace reflex cameras, as well as dedicated handheld GNSS receivers and compass
clinometers, with smartphones, which offer the equivalent functionality within a single compact
platform. Here we demonstrate that through the use of a smartphone and a portable gimbal
stabilizer, we can readily generate and register high-quality 3D scans of outcropping geological
structures, with the workflow exemplified using a mirror of a seismically active fault. The scan
is conducted with minimal effort over the course of a few minutes with limited equipment, thus
being representative of a routine situation for a field geologist.
Manuscript received 5 Mar. 2021. Revised manuscript received 19 May 2021.
Manuscript accepted 25 May 2021. Posted 1 July 2021.
© The Geological Society of America, 2021. CC-BY-NC.