Epsc 221: Volcanism

Front 1

________________ is the process by which magma from the earth's interior rises, emerges from the surface as lava and cools as volcanic rock.

Back 1

Volcanism

Front 2

_______________ is magma that has reached the surface. It generally flows well.

Back 2

Lava

Front 3

Volcanism produces threes materials: ________________, __________ and ___________.

Back 3

Lava, pyroclastic material and gases.

Front 4

Pyroclastic material is composed mostly of ____ and cinders.

Back 4

ash

Front 5

Eruption styles are related to magma __________, which is mostly a function of lava composition.

Back 5

viscosity

Front 6

__________ magma is basaltic, flows easily and does not produce explosive eruptions.

Back 6

Mafic

Front 7

___________ magma is composed of rhyolites, dacites and andesites. It is very viscous, contains volatiles and produces violent eruptions.

Back 7

Felsic

Front 8

Do explosive eruptions produce more or less pyroclastic material?

Back 8

More

Front 9

The two controls on the explosivity of an eruption are _____________ and ____________.

Back 9

Silica content and gas content.

Front 10

Rhyolite has a _________ Si content and can contain large gas volumes. It leads to more felsic magma and violent eruptions.

Back 10

high

Front 11

Basalt has a _________ Si content and cannot contain much gas. It leads to mafic magma and quiet eruptions.

Back 11

low

Front 12

There are 6 main volcano types. These are: ____________, _____________, _____________, ______________, _____________ and _____________.

Back 12

Shield, cinder cone, composite cone (stratovolcano), fissure eruptions, lava domes and calderas.

Front 13

____________ volcanoes are the largest type and have a fluid mafic magma reservoir.

Back 13

Shield

Front 14

________________ volanoes form due to gas buildup and are constructed fully of pyroclasts with no lava flow.

Back 14

Cinder Cone

Front 15

_______________________ volcanoes have large, symmetric structures and produce gas-rich magma that is generally more viscous.

Back 15

Composite Cone (stratovolcano)

Front 16

___________ ____________ volcanoes are due to long, narrow cracks that extrude mafic material with low viscosity. They can lead to lava plateaus

Back 16

Fissure Eruption

Front 17

__________ __________ volcanoes produce high-viscosity magma that often accumulates, forming a Si-rich dome.

Back 17

Lava Dome

Front 18

________________ volcanoes are large collapse depressions following eruptions or drainage.

Back 18

Caldera

Front 19

Volcanoes are most commonly found at _______________, such as mid-ocean ridges and rift zones, at ____________________, such as Japan, or as_________________ volcanoes, such as Hawaii.

Back 19

Spreading Zones, Convergence Zones, Intraplate

Front 20

To be considered active, a volcano must have had an eruption in the last ________________ years.

Back 20

10, 000

Front 21

A _____________ volcano must have an active magma chamber.

Back 21

Dorman

Front 22

An extinct volcano does not have an active magma chamber and has not had an eruption in the last ______________ years.

Back 22

10, 000

Front 23

Signs of an impending eruption include: ___________, ____________, _____________ and _____________.

Back 23

pH change, seismic monitoring, change in gas composition, change in heat flow.