Volcano Lesson 2

Question 1

What are 5 things found in a volcano?

Answer 1

Magma chamber
Pipe
Vent
Lava Flow
Crater

Question 2

beneath a volcano, magma collects in a ____

Answer 2

magma chamber

Question 3

During an eruption, the magma forces its way through ________.

Answer 3

one or more cracks in the earth’s surface

Question 4

Magma moves upward through a ___, a long tube that extends from the Earth’s crust through the top of the volcano, connecting the magma chamber to the Earth’s surface

Answer 4

pipe

Question 5

Molten rock and gas leave the volcano through an opening called a ____. Some have a single one at the top, some have them on the sides too.

Answer 5

vent

Question 6

the _____ is the spread of lava as it pours out of a vent

Answer 6

lava flow

Question 7

a _____ is a bowl shaped area that may form at the top of a volcano around the central vent

Answer 7

crater

Question 8

What is trapped in magma?

Answer 8

dissolved gases (like a can of soda)

Question 9

during an eruption, as magma rises toward the surface, the pressure of the surrounding rock on the magma ____. The dissolved gases begin to ____, forming _____. As pressure falls within the magma, the size of the gas bubbles _____ greatly. These expanding gases exert great force.

Answer 9

decreases, expand, bubbles, increases

Question 10

When a volcano erupts, the force of the expanding gases pushes ______________.

Answer 10

magma from the magma chamber through the pipe until it flows or explodes out the vent.

Question 11

Once magma escapes from the volcano and becomes ___, the remaining gases bubble out.

Answer 11

lava

Question 12

What are the 2 types of volcanic eruptions?

Answer 12

quiet or explosive

Question 13

what determines whether a volcanic eruption is quiet or explosive?

Answer 13

silica content and whether it is thin and runny or thick and sticky.
Temperature also helps determine how fluid or runny the magma is

Question 14

____ is a material found in magma that forms from the elements oxygen and silicon.

Answer 14

Silica

Question 15

2 types of magma, what materials make both types up?

Answer 15

Low-Silica, High Silica

Silica, other oxides, all other solids

Question 16

when does a volcano erupt quietly?

Answer 16

if the magma is hot or low in silica, thin/runny, flows easily. gases bubble out gently. low silica lava oozes quietly from the vent and can flow for many kilometers.

Question 17

quiet eruptions can produce different kinds of lava: Name 2. What are they?

Answer 17

pahoehoe; harden into different types of rock, forms from fast moving hot lava that is thin and runny, looks like rope-like coils

Aa; forms from cooler, thicker lava. slower moving. rough surface consisting of jagged chunks.

Question 18

Most quiet eruptions formed in the ___ islands.

Answer 18

hawaiian

Question 19

On the islands of Hawaii, lava pours from crater near the top of Kilauea. In general, the temperature of lava can range from:___ to ____. Quiet eruptions have built up the island of Hawaii over hundreds of thousands of years.

Answer 19

750 to 1175 Celsius

Question 20

A volcano erupts explosively if_______.

Answer 20

its magma is high in silica

Question 21

High silica magma is ____. It can build up in the ____, plugging it like a cork in a bottle.

Answer 21

thick and sticky.

pipe

Question 22

_____, including water vapor, cannot escape from thick magma. The trapped gases build up pressure until they explode

Answer 22

dissolved gases

Question 23

The erupting gases and steam _______

Answer 23

push the magma out of the volcano with incredible force

Question 24

Example of an explosive volcano

Answer 24

Mount St Helens in Washington state

Question 25

What happens when a volcano explodes?

Answer 25

eruption throws lava powerfully into the air, breaks into fragments that quickly cool and harden into pieces of different sizes.

Question 26

Small volcanic pieces are called

Answer 26

volcanic ash

Question 27

Pebble sized volcanic pieces are called

Answer 27

cinders

Question 28

Larger pieces range from golf ball size to the size of a car!

Answer 28

bombs

Question 29

What types of danger can happen in a quiet eruption

Answer 29

lava flows from vents ,setting fire to and often burying everything in its path; can cover large areas with a thick layer of lava

Question 30

What types of danger can happen in an explosive eruption

Answer 30

mixture of dangerous materials (hot rock and ash); can form a fast moving cloud that rushes down the sides of the volcano. (PYROCLASTIC FLOW). Landslides can also form.

Question 31

What are the stages of volcanic activity?

Answer 31

Active, dormant, extinct

Question 32

___ volcano is one that is erupting or has shown signs that it may erupt in the near future.

Answer 32

Active

Question 33

A ____ volcano or sleeping volcano is one that is expected to awaken in the future and become active

Answer 33

dormant

Question 34

___ volcano or dead volcano is one that is unlikely to ever erupt again.

Answer 34

extinct

Question 35

name an instrument a geologist may use to detect warnings or changes

Answer 35

tiltmeters, can detect slight surface changes in elevation and tilt caused by magma moving underground.

Question 36

Geologists monitor gases escaping from the volcano. They monitor the many small ____ that occur around a volcano before eruption. The upward movement of magma triggers these.

Answer 36

earthquakes

Question 37

Lastly, rising ____ in underground water may signal that magma is nearing the surface.

Answer 37

temperatures