Satellites are very important in many areas of geology, such as detecting mineral resources, measuring soil movements, studying the movements of tectonic plates and forecasting volcanic eruptions.

Photogeology is the use of photography to study the Earth. Geologists have considered it an important working process ever since a large-scale research project in New Guinea, which took place between the two World Wars, was completed.

Aerial photographs have provided information about the Earth's structure. They have also helped with geological projects that are importance to the world's economy. For example, they have locating oil and mineral deposits.

When space photography was developed, geologists soon realized that it would be very helpful to them.

Satellite photos that show large areas of the Earth's surface help geologists to learn what causes structures and patterns to form.

The enormous distance from satellites to the objects they study makes it pos¬sible to see large-scale relationships.

Satellite photographs are better than aerial photos for examining geological structures and finding mineral resources.

Satellite photography may include infrared photography, radar photography and magnetic and spectrometric measuring.

Infrared pictures can show geological structures much more distinctly than ordinary photography, as they bring out the detailed contrast between the different kinds of rock.

Fractures and faults can be seen quite clearly, even when they are covered by detritus.

Satellites can be used to find out about the Earth's resources and environmental problems such as pollution of air and water, flooding, erosion, and crop deterioration.