Pages in this set

Page 1

Preview of page 1
Key words glossary unit 4: tectonic activity and hazards



Key word Definition
Areal extent This is the volume of the area that is affected; this depends
on the magnitude and type.
Ash falls Very disruptive; they can damage buildings and plants.
Asthenosphere Second layer of the crust.
Basaltic magma (mafic)…

Page 2

Preview of page 2
Key words glossary unit 4: tectonic activity and hazards

Duration This is one of the factors of a hazard profile; the time taken
for the tectonic event to happen.
Dykes Cut across the bedding planes of the rock. Magma forms
cracks and weaknesses. It cools and solidifies before
reaching the…

Page 3

Preview of page 3
Key words glossary unit 4: tectonic activity and hazards

Katmalan eruptions There are massive ash flows; this is with explosive tephra,
hot springs and fumaroles.
Laccolith Magma cools between layers. It is smaller than a batholith.
E.g. Pine Valley mountains, Utah, USA.
Lahar This is when melt water flows it…

Page 4

Preview of page 4
Key words glossary unit 4: tectonic activity and hazards

Sills Formed parallel to bedding planes. Cracks run horizontally. It
provides a line of weakness where the magma flows. As it
cools, the magma contracts providing cracks in the rocks.
E.g. Palisades Sill, New York New Jersey, USA.
E.g. Whin Sill,…

Comments

No comments have yet been made

Similar Geography resources:

See all Geography resources »