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Curtin Department of Exploration Geophysics

What is Geophysics?

Geophysics is a non-destructive and non-invasive Earth Science that uses the very latest science and technology in instrumentation, data acquisition and advanced computer modelling and interpretation in subsurface exploration. We use seismic, magnetic, electromagnetic, radiometric and gravitational technologies and techniques to determine the structure and composition of natural (and sometimes artificial) materials below the Earth's surface without the need for drilling or excavation. 

Geophysics can be used in many diverse situations such as:

 

Geophysical Techniques

 

Geophysicists use a variety of scientific techniques to determine subsurface structures of the Earth and other bodies.

 

The main geophysical techniques used are:

 

 

Data Acquisition

 

Methods such as seismic, sonar and ground penetrating radar can be classed as active where a signal is generated and directed into the medium being analysed. Because the different layers within the medium have different densities, part of the signal is reflected back to its surface as the signal passes through the layers. Other equipment and instrumentation (geophones or hydrophones) is then used to detect the signal and record its new properties.

 

Other methods such as magnetism, electromagnetism and gravity, are passive in that instrumentation is used to detect changes in the medium's properties due to variations in its density and content. For example, a body of iron ore will have much higher magnetic and gravitational properties than the earth surrounding it.
 

Interpretation

 

Once the data has been collected in the field it can then be analysed using powerful computers and sophisticated software applications. After analysis, 2 and 3 dimensional maps of the subsurface, magnetic or gravitational structure of the test area are generated.

 

In the case of resources exploration, based on the results of the data analysis, the exploration team (made up of geophysicists, geologists, petroleum, drilling, production and reservoir engineers) will determine the most promising sites to continue with further exploration.

 

Geophysics in other fields

 

The use of geophysical technology is not limited to the resources industry. It's also used in many other areas of scientific research and exploration. Who can forget the opening scenes in Jurassic Park where Alan Grant and his team of scientists and research students use seismic technology to reveal the ancient skeleton of a velociraptor buried in the earth.

 

In Archaeology, for example, geophysics is used to uncover the remains of buried cities, walls, ancient water courses and graves among other things. Ground penetrating radar and resistivity profiling are two of the many methods used here. In Oceanography and Atmospherics geophysics is used to analyse the structure and motion of the atmosphere and oceans.

 

Today, geophysical methods are used extensively in subsurface exploration because they produce fast and accurate results and are, more importantly, non-destructive and non-invasive.

 

Helpful Links

See some of the field equipment we use here to support our teaching and research

Society of Exploration Geophysics - Virtual Geoscience Centre