Geophysics is the study of the physics of the Earth, its environment and relations with other planets in space.

It is a wide ranging field which includes the physical composition of the Earth; gravity and magnetic fields; oceans and atmosphere; internal structure and plate tectonics; and the hydrological cycle which is based upon the movement of water in different forms on, around and under the Earth's surface.

Geophysics and human needs

To bring this down to a micro level: it explores issues related to the needs of human societies such as reducing the risk of a large scale natural disaster, e.g. an earthquake and protecting the environment. 

Natural resources

This also includes issues related to the planet's natural resources and how these are used and sometimes abused. This includes an awareness of the limited supply of certain types of natural resources, such as petroleum or coal. These have become depleted over time and cannot be recycled or replaced.

Examples of natural resources include oceans, air, minerals, animals, soils and forestry.

There are two categories of natural resources:

  • Exhaustible
  • Inexhaustible

Exhaustible natural resources are those which are available in a limited supply only and will run out once that supply has been used up. Fossil fuels and minerals fall into this category.

Inexhaustible natural resources are those which are available for an indefinite period. These include the sun, wind, rain etc. These will also be depleted over a period of time but are then renewed which ensures continuity.

This renewal period varies between these resources. A rain forest takes a long time to renew compared to the relatively short period of time for agricultural crops.

Geophysical surveys

Geophysics is used to meet the needs of society; for example the gathering of data from geophysical surveys which is used in various ways such as analysing potential mineral sources.

Other applications include locating archaeological finds, determining soil thickness and decontaminating areas affected by pollution such as surface water, groundwater or sediment.

Geophysical surveys are conducted using a selection of equipment and techniques which are performed in both academia and industry. These techniques include ground penetrating radar, seismic tomography, and remote sensing.

There are companies in Hawaii who provide geophysical services such as ground penetrating radar and other similar techniques to a range of industries. For example the environmental, construction and archaeological industries will use surface or ground penetrating radar systems to discover more about the features of a particular area or building.

Environmental industries use radar systems to analyse the depth of sinkholes and subsidence caused by a downwards shift of the Earth's surface.

The construction industry uses these systems for utility detection before undertaking any building work. This enables them to assess the obstacles and risks which include potential harm to employees as well as preventing any unnecessary repairs.

Archaeological finds can benefit from these techniques when exploring the site of an ancient civilisation or require a detailed description of a place.