geophyysics

Geophysics is the physics-based study of the Earth's interior, structure, processes, and dynamic systems, using measurements of physical fields and properties. It applies quantitative methods to understand the planet from the surface to the core and also extends to other planetary bodies. It overlaps with geology, geodesy, and engineering, and contributes to both fundamental science and practical problems.

Subfields include seismology, which analyzes earthquakes and seismic waves to image the Earth's interior; gravity and magnetic methods that map density and magnetic contrasts; electrical and electromagnetic methods such as resistivity and magnetotellurics to probe conductivity; geothermal and hydrogeophysical monitoring; and geodesy, palaeomagnetism, and environmental geophysics. Exploration geophysics uses these methods to locate resources and groundwater, while environmental geophysics addresses contamination, site characterization, and geotechnical investigations.

Common tools are seismometers, gravimeters, magnetometers, magnetotelluric rigs, electrical resistivity meters, ground-penetrating radar, borehole logging, and remote sensing including InSAR. Data are interpreted through forward modeling and inverse methods, tomography, and numerical simulations, often combining multiple datasets to resolve subsurface properties such as shear velocity, density, conductivity, and permeability.

Applications range from understanding plate tectonics and mantle convection to locating oil, gas, minerals, and geothermal reservoirs; mapping aquifers; assessing avalanche, landslide, and earthquake hazards; and supporting engineering projects and environmental assessments.

Planetary geophysics applies similar techniques to other planetary bodies. The field relies on interdisciplinary collaboration among physicists, geologists, mathematicians, and engineers.