Abstract: Systems and methods for calculating gravity and gravity gradient terrain effects. The method includes a step of receiving a digital relief model (DRM) and gravity and/or gravity gradient data recorded at observation stations; a step of calculating with a computing device gravity and/or gravity gradient terrain effects at observation stations based on (i) a triangulated surface of the DRM and (ii) an adaptive triangulation method; a step of removing the gravity and/or gravity gradient terrain effects from the gravity and/or gravity gradient data to obtain gravity and/or gravity gradient terrain corrected data; and a step of generating gravity and/or gravity gradient anomalies of a surveyed subsurface based on the gravity and/or gravity gradient terrain corrected data.