OREGON STATE UNIVERSITY

Glossary beginning with T

Volcano Term Definitions

t
Talussearch for term

A slope formed a the base of a steeper slope, made of fallen and disintegrated materials.

Tephrasearch for term

Materials of all types and sizes that are erupted from a crater or volcanic vent and deposited from the air.

Tephrochronologysearch for term

The collection, preparation, petrographic description, and approximate dating of tephra.

Tiltsearch for term

The angle between the slope of a part of a volcano and some reference. The reference may be the slope of the volcano at some previous time.

Trachyandesitesearch for term

An extrusive rock intermediate in composition between trachyte and andesite.

Trachybasaltsearch for term

An extrusive rock intermediate in composition between trachyte and basalt.

Trachytesearch for term

A group of fine-grained, generally porphyritic, extrusive igneous rocks having alkali feldspar and minor mafic minerals as the main components, and possibly a small amount of sodic plagioclase.

Tremorsearch for term

Low amplitude, continuous earthquake activity often associated with magma movement.

Tsunamisearch for term

A great sea wave produced by a submarine earthquake, volcanic eruption, or large landslide.

Tuffsearch for term

Rock formed of pyroclastic material.

Tuff Conesearch for term

A type of volcanic cone formed by the interaction of basaltic magma and water. Smaller and steeper than a tuff ring.

Tuff Ringsearch for term

A wide, low-rimmed, well-bedded accumulation of hyalo-clastic debris built around a volcanic vent located in a lake, coastal zone, marsh, or area of abundant ground water.

Tumulussearch for term

A doming or small mound on the crest of a lava flow caused by pressure due to the difference in the rate of flow between the cooler crust and the more fluid lava below