| Volcanism, also spelled vulcanism, any of various processes and phenomena associated with the surficial discharge of molten rock, pyroclastic fragments, or hot water and steam, including volcanoes, geysers, and fumaroles. |
| As a marine geologist, his research focuses on the deep-sea vulcanism of the Juan de Fuca Ridge in the northeast Pacific Ocean. |
| In fact, the cataclysm may have been a combination of vulcanism and bolide impact. |
| Five of the twelve processes, including vulcanism, are generally considered as geological, since they involve processes which created the underlying bedrock over which rivers flow. |
| From vulcanism to the extinction of species to global climate change and on to creation itself, she tackles complex topics with dexterity. |
| Valleys formed in grabens are commonly called rift valleys and may exhibit features of vulcanism often associated with graben formation. |
