volcan-, vulcan- +

Produced by completely concealed volcanic action.

In geology, a reference to the combined action of volcanoes and streams, as in beds of volcanic ash deposited by a river.

This is one of the longest words in the English language and is divided into the following segments: pneu, mono, ultra, micro, scopic, silico, volcano, coni, osis; and together they mean, "miner's lung disease", or "a disease of the lungs caused by the inhalation of very fine silicate, or quartz dust, and occurring especially in the lungs of miners".

Pertaining to or produced by a pseudo-volcano.

A large crater or circular hollow believed not to be associated with volcanic activity; e.g., a crater that is possibly meteoritic in origin but may be the result of phreatic explosion or cauldron subsidence.

1. A volcano consisting of layers of lava alternating with ash or cinder.
2. A volcano that is composed of alternating layers of lava and pyroclastic material, along with abundant dikes and sills. Viscous, intermediate lava may flow from a central vent. Example: Mt. Fuji in Japan.

1. Characteristic of, pertaining to, situated in or upon, formed in, or derived from volcanoes.
2. Discharged from or produced by volcanoes; such as, volcanic mud.
3. Characterized by the presence of volcanoes; a volcanic area.
4. Suggestive of or resembling a volcano; potentially explosive; volatile: "The mother had a volcanic reaction when her son knocked the vase and flowers off the table."

Fine pyroclastic material.

The term usually refers to the unconsolidated material but sometimes is also used for its consolidated counterpart, tuff.

A water-deposited composite rock containing more than 50% volcanic material: A volcanic conglomerate consists particularly of coarse pyroclastics.

A steep-sided, rounded mass of viscous lava forming a dome-shaped or bulbous mass over a volcanic vent.

A seismic disturbance that is due to the direct action of volcanic forces or one whose origin lies under or near a volcano, whether active, dormant, or extinct.

A natural glass produced by the cooling of molten lava, or a liquid fraction of it, too rapidly to permit crystallization.

Examples are obsidian, pitchstone, tachylyte, and the glassy mesostasis of many extrusive rocks.

A mixture of water and volcanic ash formed either on land or at the time of eruption.

A mass of hardened volcanic magma that has been thrust upward into a volcanic cone by subterranean pressure, remaining upright after the surrounding material has been stripped away by erosion.

Composed chiefly of fragments of volcanic origin, as agglomerate, tuff, and certain other rocks; pyroclastic.