This work was designed to present a case study of an erosion process on land located in Mairiporã. This process focuses directly on environmental assessments and geological structures, based on geophysical surveys. Two geophysical processes were used, Georadar and Electroresistivity. These surveys were combined in order to get an idea of what was happening on the ground as a result of the erosion process.However, the area investigated provides a guide for this adjustment to be carried out before any construction process, as it avoids any damage to the post-built structure.Preliminary assessment is the main way to avoid future problems with erosion processes.