In order to understand geophysics, you must first know that physics is the science of matter and its interactions. Therefore, since the prefix geo pertains to the earth, then geophysics is a branch of geology; geology the study of the whole earth. And what a fascinating study it is, you are learning. These two sciences are alike in that geology is the study of the science of the whole earth and geophysics is particularly concerned with the activity of the earth. Yet it too has its branches such as meteorology, oceanography and seismology.
The basic difference, however, between the two sciences, geology and geophysics, is that geophysics uses instruments and measuring devices to obtain specific information. The depths, widths and velocity, intensity, and probabilities of what is happening or what could happen when earthquakes, tornadoes, or hurricanes happen, is what the science of geophysics is all about.
Meteorology or study of the weather is one of most useful sideline sciences of geophysics. It tracks weather patterns and keeps us alert to the possibility of disastrous weather conditions. Satellites are communication devices used in weather predictions and mapping of weather probabilities that keep us alert to where it's snowing, raining, and where the sun is shining as these 'orbit the earth' is another.
Oceanography is using the science of geophysics to learn about the ocean and its habits and its secrets. It is important that seamen know of its underground currents and its depths so that ship can safely navigate its water. When earthquakes happen underneath the ocean instead of underneath the land mass then the gigantic wave activity often cause tidal waves known as tsunamis. These have nothing to do with the tides however and are the result of colliding plates underneath the ocean.
In 1703, in Awa Japan 100,000 people were swept away with the resulting waves from the force of the energy produced by one such tsunami; in 1883, the island of Krakatau along with 36,000 people met the same fate. And in the news of only a year or so ago another disaster of the same magnitude in the same general area has the world still reeling from the loss.
How important, then, is geophysics? It is enormously important, and one of the ways it is important is in the alerting of those in charge of protecting people in the area of the possibility of such an occurrence. In other words, warnings go out to people living near the ocean in the areas that the explosive activity aims toward; it tells them to move to higher grounds.
Often we hear warnings on television directed to such and such people to beware of such and such after effects from an under ocean earthquake. Hopefully many of these are only warnings, but this is an important job of seismologists to keep us on alert.
Seismology is the study of these earthquakes. Their intensity is measured by an instrument known as the Richter scale. These can occur on land or under the ocean. An earthquake measuring 6.5 or above is serious indeed.
There are other functions of geophysics other than those of humanitarian purposes and these are explorations for commercial uses. Knowledge of geophysics is useful in searching for new oil and gas fields and finding out what mineral and what elements are found where and how to better use them in our everyday lives.