A volcanologist is a scientist who studies volcanoes, including their structure, composition, and behavior. They also study the effects of volcanic activity on the surrounding environment and the potential hazards associated with them. Volcanologists use a variety of tools and techniques to study volcanoes, including field observations, remote sensing, and laboratory experiments. They may also work with other scientists, such as geochemists, geophysicists, and meteorologists, to gain a better understanding of volcanic processes.