The study of the physical material
The study of the physical material of the Earth dates back at least to ancient Greece when Theophrastus wrote the work Peri Lithon. During the Roman period, Pliny the Elder wrote in detail of the many minerals and metals, then in practical use – even correctly noting the origin of amber.

Geological principles
In the field of civil engineering, geological principles and analyses are used in order to ascertain the mechanical principles of the material on which structures are built. This allows tunnels to be built without collapsing, bridges and skyscrapers to be built with sturdy foundations, and buildings to be built that will not settle in clay and mud.
Environmental problems
Geology and geologic principles can be applied to various environmental problems such as stream restoration, the restoration of brownfields, and the understanding of the interaction between natural habitat and the geologic environment. Groundwater hydrology, or hydrogeology, is used to locate groundwater.
Obtaining data
Geologists and geophysicists study natural hazards in order to enact safe building codes and warning systems that are used to prevent loss of property and life. Geologists also obtain data through:
Stratigraphy
Boreholes
Core samples
Ice cores
Physical material
The study of the physical material of the Earth dates back at least to ancient Greece when Theophrastus (372–287 BCE) wrote the work Peri Lithon (On Stones). During the Roman period, Pliny the Elder wrote in detail of the many minerals and metals, then in practical use – even correctly noting the origin of amber.