VOLCANOLOGY

also spelled Vulcanology, scientific discipline concerned with all aspects of volcanic phenomena. Volcanology deals with the formation, distribution, and classification of volcanoes, as well as with their structure and the kinds of materials ejected during an eruption (e.g., lava, dust, ash, and gas). It also involves research on the relationships between volcanic eruptions and other large-scale geological processes, such as mountain building and earthquakes. One of the chief objectives of this research is determining the nature and causes of volcanic eruptions for the purpose of predicting their occurrence. Another practical concern of volcanology is securing data that may aid in locating commercially valuable deposits of ores, particularly those of certain metallic sulfides. Interest in volcanic phenomena extends back to ancient times. The eruption of Vesuvius in AD 79 was recorded in considerable detail by Pliny the Younger. Studies of volcanoes, however, were not conducted systematically until the early 19th century. Since that time volcanology has become an important branch of physical geology. Specialists in the field, using the principles and methods of geophysics and geochemistry and the tools of seismology, have obtained much knowledge of processes occurring deep within the Earth's interior.