Lesson 5

Question 1

Advantages of volcanoes

Answer 1

Serve as a foreign and local tourist attraction

Help improve the quality of the surrounding soil by
providing nutrients for crops.

Their geothermal component is also an excellent source
of energy and recreational facilities.

Question 2

Disadvantages of volcanoes

Answer 2

Pose a threat on the communities surrounding the volcano

Bury adjacent communities in lahar and affect global climate

People living in areas distant from the site can also be affected by
the ash fall, poisonous gases, and lahar.

Question 3

a vent on the earth’s surface that opens
downward to a pool of molten rock, debris, and gases. Its
formation involves the process of subduction.

Answer 3

volcano

Question 4

takes place when two plates converge.

Answer 4

subduction

Question 5

the place where the two plates
converge and the volcano is formed (DOST-PHILVOCS,
n.d.).

Answer 5

subduction zone

Question 6

The thickness of the magma caused by____makes it difficult for gases to be released easily.

Answer 6

silica content

Question 7

forms inside the steep cone and this

collects the gases.

Answer 7

magma chamber

Question 8

When the_____accumulate, the volcano erupts because
the pressure rises within the chamber as it cannot contain
the magma.

Answer 8

gases

Question 9

can harm people and surroundings.

Answer 9

erupts explosively, expels lava, rocks, ash, and gas

Question 10

The occurrence of ____(4)is also possible.

Answer 10

earthquake, lahar flow, debris,

avalanche, or tsunami

Question 11

large underground pool of magma

Answer 11

magma chamber

Question 12

it is magma, yet this is the term once it reaches the surface

Answer 12

lava

Question 13

bowl-shaped basin in the top of the volcano

Answer 13

crater

Question 14

central tube which magma travels through

Answer 14

vent

Question 15

eruptions from other vents may build up_____on the flanks

Answer 15

secondary cones

Question 16

materials thrown out by the volcano

Answer 16

ash, steam and gas

Question 17

larger materials thrown out by the force of eruption

Answer 17

volcanic bombs

Question 18

are steep-sided and cone-shaped,
made up of layers of ash and lava
and containing sticky lava which
doesn’t flow very far.

Answer 18

composite volcanoes

Question 19

have gently sloping sides and
runny lava that covers a wide
area. Gases escape very
easily from shield volcanoes.

Answer 19

shield volcanoes

Question 20

currently erupting or is showing signs of

eruption. Have erupted within the last 600 years.

Answer 20

active

Question 21

has erupted and then entered a

long period of inactivity.

Answer 21

potentially active

Question 22

has not shown any sign of activity for a long
period of time. Has no record of volcanic eruption in the
past thousand years.

Answer 22

inactive

Question 23

volcanic eruption hazards

Answer 23

lava flow
pyroclastic flow
tephra falls
ballistic projectiles 
volcanic gas
lahar

Question 24

mass of magma that flows down the slope
of the volcano at a rate of 3 km/d (slightly high viscosity)
or 45 km/h (low viscosity).

Answer 24

lava flow

Question 25

hot dry masses of fragmented
volcanic materials that move along a slope and in contact
with ground surface at a speed greater than 60 km/h.

Answer 25

pyroclastic flow

Question 26

showers of fine to coarse-grained
volcanic materials and other airborne products of volcanic
eruption.

Answer 26

terphra falls

Question 27

rocks that are released into

the air by an erupting volcano.

Answer 27

ballistic projectiles

Question 28

one of the basic components of

magma or lava.

Answer 28

volcanic gas

Question 29

flowing mixture of volcanic debris and water.

Answer 29

lahar

Question 30

is the downward movement of soil, rocks, and

earth materials along a slope.

Answer 30

landslide

Question 31

is a slow or gradual

movement of soil

Answer 31

creep

Question 32

is the downslope flowage of

soft and unconsolidated materials.

Answer 32

slump

Question 33

is the slow
to rapid downslope movement of
unconsolidated soil and rock
details.

Answer 33

Rock and debris slide

Question 34

is the free falling
movement of massive rocks from a
cliff or steep slopes.

Answer 34

rock fall

Question 35

is the rapid flowage of

debris and other rock materials.

Answer 35

debris flow

Question 36

is the mass movement
characterized by a flowing mass of
mud along the flank of a volcano.

Answer 36

mud flow

Question 37

Geologic formations caused by exposure to water, erosion,

and ground movement.

Answer 37

sinkholes

Question 38

usually formed by erosion of bedrocks
composed of soft minerals and rocks such as salt, gypsum,
limestone, dolomite, and other materials that belong to the
evaporate or carbonate classes of rocks.

Answer 38

sinkholes

Question 39

Acid water underground and rainwater dissolve the rocks

and form underground passage for water called

Answer 39

conduits