Lesson 5 Flashcards
Advantages of volcanoes
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.
Disadvantages of volcanoes
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.
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.
volcano
takes place when two plates converge.
subduction
the place where the two plates
converge and the volcano is formed (DOST-PHILVOCS,
n.d.).
subduction zone
The thickness of the magma caused by____makes it difficult for gases to be released easily.
silica content
forms inside the steep cone and this
collects the gases.
magma chamber
When the_____accumulate, the volcano erupts because
the pressure rises within the chamber as it cannot contain
the magma.
gases
can harm people and surroundings.
erupts explosively, expels lava, rocks, ash, and gas
The occurrence of ____(4)is also possible.
earthquake, lahar flow, debris,
avalanche, or tsunami
large underground pool of magma
magma chamber
it is magma, yet this is the term once it reaches the surface
lava
bowl-shaped basin in the top of the volcano
crater
central tube which magma travels through
vent
eruptions from other vents may build up_____on the flanks
secondary cones
materials thrown out by the volcano
ash, steam and gas
larger materials thrown out by the force of eruption
volcanic bombs
are steep-sided and cone-shaped,
made up of layers of ash and lava
and containing sticky lava which
doesn’t flow very far.
composite volcanoes
have gently sloping sides and
runny lava that covers a wide
area. Gases escape very
easily from shield volcanoes.
shield volcanoes
currently erupting or is showing signs of
eruption. Have erupted within the last 600 years.
active
has erupted and then entered a
long period of inactivity.
potentially active
has not shown any sign of activity for a long
period of time. Has no record of volcanic eruption in the
past thousand years.
inactive
volcanic eruption hazards
lava flow pyroclastic flow tephra falls ballistic projectiles volcanic gas lahar
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).
lava flow
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.
pyroclastic flow
showers of fine to coarse-grained
volcanic materials and other airborne products of volcanic
eruption.
terphra falls
rocks that are released into
the air by an erupting volcano.
ballistic projectiles
one of the basic components of
magma or lava.
volcanic gas
flowing mixture of volcanic debris and water.
lahar
is the downward movement of soil, rocks, and
earth materials along a slope.
landslide
is a slow or gradual
movement of soil
creep
is the downslope flowage of
soft and unconsolidated materials.
slump
is the slow
to rapid downslope movement of
unconsolidated soil and rock
details.
Rock and debris slide
is the free falling
movement of massive rocks from a
cliff or steep slopes.
rock fall
is the rapid flowage of
debris and other rock materials.
debris flow
is the mass movement
characterized by a flowing mass of
mud along the flank of a volcano.
mud flow
Geologic formations caused by exposure to water, erosion,
and ground movement.
sinkholes
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.
sinkholes
Acid water underground and rainwater dissolve the rocks
and form underground passage for water called
conduits
