Geologists study the internal and external processes that have shaped the Earth over the past 4.6 billion years. They are experts in the origin, evolution and structures of our planet, and the ways in which it continues to change today.
In geologic surveying, geologists study and map the distribution, by type, of rocks and other features on the Earth’s surface. They observe how through geological processes the rocks have been folded and fractured or even changed (for example, the collision of continents).
Geologists establish the age of rocks and track their evolution, for example by looking for which fossils they contain or by calculating the decay of radioactive elements in their mineral grains.
This information leads to the production of maps and databases, which are essential tools in any field in which the geologist applies his knowledge.
Some geologists monitor and watch earthquakes and volcanoes, using their research to predict eruptions and earthquakes, thus saving lives. For example, examining the distribution of lava and ash from past volcanic eruptions allows them to predict where the most severe effects of a new eruption are likely to occur.
Likewise, the study of the erosion of mountain ranges by natural erosion and human activity allows geologists to save lives by warning of mudslides and potential landslides.
One of the main areas in which geologists apply their knowledge is in the search and direction of the extraction of natural resources. Geologists understand the conditions and processes necessary for resources such as water, oil, gas, and minerals to form, and therefore have a good understanding of where those resources can be found.
Natural resources also include the rocks themselves, such as slate for roofs and limestone for agriculture and construction.
In the search for natural resources, geologists use geological maps and reports (including seismic surveys), aerial photographs, and satellite images. They must be very sure that they have found the correct zone to mine or drill.
Geologists also need to know what type of structure is being drilled, and how stable and safe it is for exploration.
To find this information, geologists use different techniques. They can investigate rock layers by dropping sensitive geophysical instruments and cameras into drill holes and create models of the rock layers on a computer.
They take rock and seafloor samples to check their physical properties, such as the type and thickness of the underlying bedrock. They must take into account faults and weak points in the area, which can cause drainage problems or instability.
Geologists also look for alternative energy sources. For example, they investigate geothermal energy potential (the heat stored inside the Earth). Currently, Iceland gets most of its energy from heat stored in molten volcanic rocks.
The hydrogeologists they are experts in finding and directing groundwater resources. This work is especially important in very hot countries, where most of the water must be underground.
In any type of civil engineering project, geologists must carefully study the structures involved in it, to ensure safety at work, as well as to minimize environmental impact.
These professionals play an important role in tackling environmental issues. For example, they help municipal authorities to choose safe landfills, ensuring the suitability of surrounding rocks (fluid seeps can contaminate nearby rivers). They also advise on environmental issues such as what to do with abandoned mines and land contaminated by industrial waste.
In addition, geologists teach and conduct research in universities and museums and teach in schools and institutes.