Geochemists: Study the nature and distribution of chemical elements in groundwater and Earth materials in order to better understand Earth’s compositional characteristics

Geologists: Study the composition, physical materials and history of Earth, usually with the goal of understanding the nature of processes that have formed the geologic record

Geophysicists (includes geodesists, seismologists and geomagneticists): Use mathematics and physics to study Earth's motions, gravitational field, earthquakes and magnetic information to better understand geodynamic processes and improve models of Earth’s interior

Mineralogists: Analyze and classify minerals and minerals systems, usually with the goal of understanding the nature of formation and/or to locate new mineral resources

Paleontologists: Study fossils to trace the evolution of plant and animal life and to decipher the geologic history of the Earth

Sedimentologists: Study the nature, origin and distribution of sediments (such as gravel, sand, silt and mud) and further understanding of the processes involved in sediment accumulation and the deposits they contain

Stratigraphers: Examine the formation and layering of stratified rocks in order to understand the environment in which they formed and clues they hold about Earth-surface processes of the past

Volcanologists: Investigate volcanic phenomena to better predict the potential for future eruptions and the nature of volcanic-related hazards to human health and welfare

Glacial geologists: Study the physical properties and movement of glaciers and ice sheets, and often are involved in discussions around climate change

Hydrogeologists: Study the quantity, composition, distribution, circulation and physical properties of surface water and groundwater; often play a role in decisions involving resource management and land use

Engineering geologists: Apply geologic principles to civil and environmental engineering, often advising on major construction projects, environmental remediation, resource management and natural-hazard reduction

Oceanographers: Study Earth’s oceans and coastal waters to provide important evidence bearing on coastal process, undersea geology, biological evolution, broad-scale oceanic circulation patterns and climate change