Structural Geology: An Overview of the Processes and Structures That Shape the Earth’s Surface Geology, the study of the Earth’s physical structure and substance, is a vast and complex field that encompasses many different sub-disciplines. One of these sub-disciplines is known as structural geology, and it plays a critical role in our understanding of how the Earth’s surface is shaped and altered over time. So, what exactly is structural geology? In simple terms, it is the study of the deformation and changes in the Earth’s crust and how they result in different geological structures such as folds, faults, and joints.