An Introduction to Geophysics

Geophysics is the study of the earth’s properties by applying physical theories and using instruments for measurement. Since antiquity men have been studying the earth’s properties in order to predict earthquakes, but real progress happened in the 1500’s and has continued since then.

Scientists began working to understand how magnetism and gravity are related to earthquakes. Magnetism is an attraction to metals such as iron, nickel, cobalt, and their alloys. Its main character is a magnetic force. Though metals are more strongly influenced by magnetism all materials are under its influence to a degree.

One of its particular manifestations in physics is that it’s a component of electromagnetic waves. Light is an electromagnetic wave.

Magnetism is now used to help predict the frequency of earthquakes by utilizing the fact that earthquakes happen in clusters. They can’t yet use this information to predict exactly when an earthquake will occur, but when there is an earthquake statistics show others will follow.

Heat is a factor in magnetism and when the heat in an atom is at an intermediate temperature according to “Curie temp,” then instead of the clusters of atoms moving in different directions like when under high temperature, aligned clusters form and these groups move in the same direction, though there is more than one grouping.

Thus, heat is one of the properties that cause earthquakes and this is also related to gravity. That is when earthquakes occur they change the local gravity. Massive sections of the earth called continental plates move and meet at fault lines and cause the change in local gravity.

Besides the study of magnetism and gravity these are some of the other areas studied in geophysics: lithospheric plates, refraction seismology, crustal roots, ocean basins, isostatic equilibrium, and subduction.

In more depth the study of geophysics is an interdisciplinary effort involving Mathematics, Physics, and Geophysics in the course load for students. Geophysics is divided into two large parts: Exploration Geophysics and Global Geophysics. They study the structure and composition of the earth.

There are many subdivisions of geophysics including: oceanography, atmospheric physics, climatology, petroleum geophysics, environmental geophysics, engineering geophysics, and mining geophysics.

What other work do geophysicists do? Usually they are part of a team with other earth scientists like geologists and engineers. They work on environmental, construction and exploration problems.

They use instruments and computing to for measuring physical properties. They measure density, electrical resistivity, electrical fields, radioactivity of rocks, velocity of sound waves transmitted through the ground, changes in gravity and magnetic fields of the earth, and reflection of radio signals coming from rocks near the surface of the earth.

What do geophysicists use these measurements for? They use these measurements to find oil, natural gas, metals, diamonds, potash, and coal. They also identify environmental problems and to calculate the qualities of an area, judging how suitable they are for dam building and construction sites.

Geophysicists get jobs working in consulting, oil, academic and government employment.  

Geophysics is an exciting field of endeavor that properly utilized can improve our living environment and teach us about our home—the earth.