OREGON STATE UNIVERSITY

Glossary beginning with T

Volcano Term Definitions

t
Talus

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

Tephra

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

Trachyte

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.

Tsunami

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

Tuff Cone

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

Tuff Ring

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.

Tumulus

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