Geological Science Test 2

Front 1

Scoria Cone

Back 1

-also called cinder cones
-usually basaltic
-several hundred meters high

Front 2

Shield Volcano

Back 2

gentle slopes
usually basaltic with scoria and ash
size ranges from a kilometer across to huge mountains

Front 3

Composite Volcano

Back 3

Symmetrical mountains
Interlayered lava flows, pyroclastic deposits, mudflows
Mostly andesite, but also contains felsic and mafic rocks

Front 4

Volcanic Dome

Back 4

dome-shaped constructed feature
Solidified lava with volcanic ash and rock fragments
Very viscous felsic or intermediate magma

Front 5

Fissure

Back 5

magma rises through a dike
can erupt large volume of basalt

Front 6

Caldera

Back 6

volcano-related topographic depression
erupts huge volume of magma, mostly as volcanic ash
rhyolitic domes build inside caldera after eruption

Front 7

Lava Flow

Back 7

Magma erupts onto surface and flows away

Front 8

Lava Fountain

Back 8

Gas propels molten pieces lava into air

Front 9

Dome

Back 9

viscous lava piles up around vent

Front 10

Eruption Column

Back 10

volcanic ash, pumice, rock fragments ejected into air

Front 11

Pillow Basalt

Back 11

Lava erupts into water forming rounded shapes called pillows

Front 12

Eruptions into Water

Back 12

seawater boils, producing steam, and add new land

Front 13

Lava Caused Fire

Back 13

flammable structures and vegetation may be burned by lava flow

Front 14

Volcanic Ash

Back 14

can reach heights of several kilometers and impact areas far downwind

Front 15

Pyroclastic Flows

Back 15

Violent eruptions of hot gases, ash, angular rock fragments

Front 16

Lava Flows and Domes

Back 16

Can erupt from summit of volcano or on flanks
Moderate to high viscosity so move slowly
Viscous lava breaks into blocks

Front 17

landslides and mudflows

Back 17

Large volcanoes have snow and rain at summit
When volcano erupts, snow melts causing a mudflow called a lahar
Steep slopes, loose rocks, and loose ash contribute to hazards of mudflows

Front 18

Formation of a Caldera

Back 18

Stage 1
felsic magma accumulates in magma chambers
Stage 2
Magma reaches the surface and erupts
Roof of magma chamber subsides as magma chamber is evacuated
Circular fractures form
Stage 3
Eruption of felsic magma forms eruption columns and pyroclastic flows
Much falls back into caldera
Landslides off steep walls
Some tephra escapes and covers surrounding area
Stage 4
Magma rises through fractures along edge and interior, forming domes

Front 19

Explosive Eruption

Back 19

volcano eruption generates seismic waves as does the movement of liquid magma
Movement along faults: normal faulting occurs as blocks slide into emptying magma chamber

Front 20

Slope Failure

Back 20

unstable rocks on steeps sides of a volcano may fail during shaking

Front 21

Landslides

Back 21

Hawaii is subject to massive underwater landslides, capable of generating large tsunamis

Front 22

Meteoroid Impacts

Back 22

meteoroid impacts are likely to generate largest seismic wave, some perhaps causing mass extinctions

Front 23

Explosions

Back 23

nuclear tests create a distinct pulse-like seismic signal

Front 24

seismometer

Back 24

cylinder is wrapped in paper and rotates slowly at a known rate; a pen is suspended above the paper so that it draws a continuous line as the cylinder rotates

Front 25

Creep

Back 25

slow, continuous movement in weak materials; occurs on most slopes but at different rates

Front 26

Debris Slide

Back 26

Unconsolidated but detaches along some interface

Front 27

Earth Flow

Back 27

weak, with matrix of fine-grained materials; moves like wet concrete; also called mudflow