Volcanic

Volcanic is an adjective describing anything related to volcanoes or volcanism—the processes, features, and phenomena associated with volcanic activity. The term is used in geology, geophysics, and related disciplines, and in the names of rocks and deposits produced by eruptions.

Volcanic activity includes effusive eruptions, which produce lava flows that construct lava domes and shield volcanoes, and explosive eruptions that eject ash clouds, pumice, and volcanic bombs. The style and scale of an eruption depend on magma viscosity, gas content, temperature, and tectonic setting.

Volcanic rocks range from low-viscosity basalt to high-viscosity rhyolite and andesite, forming different volcano types. Ejected materials include tephra—ash, pumice, tuff—and volcanic glass. Gases such as water vapor, carbon dioxide, and sulfur dioxide are released during eruptions and can affect air quality and climate.

Hazards include lava flows, ash fall, pyroclastic density currents, eruptions of volcanic bombs, and lahars. Monitoring relies on seismology, ground deformation measurements, gas sensing, and satellite observations to forecast eruptions and mitigate impacts.

Globally, volcanic activity concentrates along tectonic plate boundaries, especially the Pacific Ring of Fire. Volcanic processes shape landscapes, create fertile soils, and provide geothermal resources, while posing risks to nearby populations.