These resources describe the 3D geophysical inversion modeling of gravity data at the FORGE site near Milford, Utah. FORGE is the Frontier Observatory for Research in Geothermal Energy and the site in Utah has been selected by the U.S. Dept. of Energy for a 5-year R&D program to test technologies for the development of Engineered Geothermal Systems (EGS). 3D modelling of gravity data at the FORGE site is to help characterize the subsurface geologic framework. Specifically, modelling of gravity data in 3D, used in conjunction with rock density measurements and other subsurface geologic information can provide an independent test of an existing 3D geologic model (e.g. Witter et al., 2018). Such an exercise can be useful for reducing uncertainty in 3D geologic models (Witter et al, 2019).

This is the topical report that wraps up the work and results achieved during Utah FORGE Phase 2C. The zip file includes several folders containing (1) an overview; (2) the results; (3) the lessons learned; and (4) the conclusions. It also contains a folder containing appendices including (1) the updated permitting inventory; (2) the updated site characterization data inventory; (3) the updated conceptual geological model; and (4) the stakeholders engagement and outreach status.

This package contains principal facts for new gravity data collected September - November 2017 in support of the Fallon FORGE project. Also included are rock core density and magnetic susceptibility data for key core intervals, used in modeling 2D and 3D gravity inversions. Individual metadata summaries are provided as .pdf within each attached archive.