Chapter 4Chapter 4VolcanoesVolcanoes

calderacalderaA large circular

depression, or basin, at the top of a volcano

cinder cone cinder cone volcanovolcano

a kind of volcano, usually small and steep-sloped, that is formed from layers of cinders which are sticky bits of volcanic material

composite cone composite cone volcanovolcano

A kind of volcano formed when explosive eruptions

of sticky lava alternate with quieter eruptions of

volcanic rock bits

hot spothot spotA place deep within Earth’s

mantle that is extremely hot and contains a chamber of magma

island arcisland arcA chain of volcanoes

formed from magma that rises as a result of an

oceanic plate sinking into the mantle

lavalavaMagma that flows out onto

Earth’s surface from a volcano

magmamagmaThe hot molten rock deep inside the earth

riftingriftingThe process by which magma rises to fill the

gap between two plates that are moving apart

seismometerAn instrument that detects and records

Earth’s movements

shield volcanoshield volcanoA kind of volcano that is large

and gently sloped and that is formed when lava flows quietly from a crack in the

earth’s crust

volcanovolcanoAn opening in Earth’s crust through which hot gasses, rock fragments and molten

rock erupt