Volcanic Eruptions - VOLCANOES AND TYPES OF ERUPTION Flashcards
volcanic landforms (4 kabuok)
Lava Flow
Lava Dome
Continental Flood Basalt
Volcanoes
formed when lava eventually cools and solidifies into an igneous rock body
Lava Flow
two types of lava flow
aa ; pahoehoe
is a Hawaiian term for lava flows that have a rough rubbly surface composed of broken lava blocks
Aa
broken lava blocks are called
clinkers
is a Hawaiian word used to describe a lava flow with a smooth, ropy surface
pahoehoe
are steep-sided mounds that were formed from viscous lava (rhyolitic) and can act like a plug when it begins to solidify
lava domes
what type of magmas are lave domes made of?
rhyolitic
t or f: lava domes can act like a plug when it begins to solidify and thus allow pressure to build in the magma chamber and result in a more explosive eruption
T
example of a continental flood basalt
Deccan Traps, India
formed when large volumes of basaltic lava will flow onto the surface along large fracture zones
Continental flood basalt
an accumulation of extrusive materials around a vent through which lava, gas, or pyroclastic are ejected
volcanoes
continental flood basalts are formed when large volume of basaltic lava will flow onto the surface along ______
large fracture zones
t or f: volcanoes are accumulation of extrusive materials around a vent or sometimes a fault or fracture
T
volcanoes are accumulation of extrusive materials around a vent (sometimes a fault or fracture) through which ___, ___, or ___ are ejected
lava, gas, pyroclastics
three types of volcanic cones:
cinder
composite
shield
a volcanic vent can coincide with a fault or fracture, resulting in a linear extrusion known as
fissure eruption
relatively small and is formed when lava is ejected into the air and cools into pyroclastic material called cinders, which then fall and accumulate around the vent
cinder cones
t or f: cinder cones can be formed along another composite or shield volcano
T
example of a cinder cone volcano
Taal Volcano
composite cone volcanoes are also know as
stratovolcano
are cone-shaped volcanoes with steep slope
composite cone volcanoes
composite cone volcanoes consist of alternating layers of
pyroclastic material and lava flows
what type of magma is generally associated with composite cone volcanoes?
andesitic to felsic magmas
magmas in composite cone volcanoes are _____ and ____
viscous and gas-charged
examples of composite vocanoes
Mayon Volcano, Bicol Region
Mt. Fuji, Japan
type of volcano that are exceptionally large landforms composed primarily of basaltic lava flows
shield volcanoes
shield volcanoes has broad cross-sectional shape due to _______ which can travel considerable distances from the vent
low viscosity of basalt
shield volcanoes has a ______ type of eruption as basaltic magma contains low amount of dissolved gases and has low viscosity
quiescent
example of a shield volcano
Mauna Loa
t or f: shield volcanoes can be formed above a hotspot
T
what is the largest ACTIVE volcano on Earth
Mauna Loa
what is the most active volcano on earth
Mt. Etna ?
a circular depression where lava and pyroclastic material is being ejected
Crater
a circular depression that forms after an eruption when large volumes of magma are ejected from a shallow magma chamber, leaving it empty and thus causing it to subside / collapse
caldera
example of a filled caldera
Crater Lake in Cascade Range in Oregon
how many active volcanoes in the Philippines?
24
northernmost active volcano in the philippines
Mt. Iraya
southernmost active volcano in the philippines
Mt. Bud Dajo
Southernmost volcano in Luzon
Mt. Bulusan
6 volcanoes along Philippine Trench
Mayon, Bulusan, Isarog, Iriga, Biliran, Cabalian
westernmost volcano in the Philippines
Pinatubo
easternmost volcano in the Philippines
Leonard Kniaseff
top 6 most active volcanoes in the Philippines
Mayon, Taal, Pinatubo, Bulusan, Hibok-hibok, Kanlaon
mt. apo is what kind of volcano based on how active it is
potentially active
what is the nearest active volcano to Davao City
Lake Leonard Kniaseff
morphologically young looking but with no historical or analytical records of eruption
Potentially active
no recorded eruptions, physical form has been intensively weathered and eroded, bearing deep and long gullies
inactive
erupted within the last 10,000 years
active
a zone of molten material where magma accumulates and occurs at a considerable depth
magma chamber
the ______ caused by the overlying rock gives the molten material within the magma chamber a tremendous amount of _____
confining pressure ; fluid pressure
as magma rises and encounters less confining pressure, it _______ on the surrounding rocks, thereby creating ____ and ____ and subsequent ______.
expands and pushes outwards;
fractures and faults;
earthquakes
these provide pathway for the magma to the surface
fractures and faults
if the overlying rock at some point can no longer capable of containing the ______, then significant amount of magma can make its way to the surface resulting in a ______
fluid pressure ; volcanic eruption
volcanic eruptions occur when
pressurized magma breaches the surface
are associated with more viscous and gas-charged magmas in which the dissolved gases rapidly decompress, ejecting rocks and ash into the atmosphere
Explosive eruptions
are associated with hot fluid magma containing less dissolved gas, in which case generates lava fountains and lava flows
nonexplosive eruptions or quiescent eruption
quiescent eruptions generate
lava fountains and lava flows
t or f: subduction zone volcanoes tend to erupt in an explosive manner because their andesitic magmas usually contain large volumes of gas (mostly carbon dioxide)
F (mostly water vapor)
hot spot volcanoes located in the interior or plate also erupt in a _____ manner, as their rhyolitic magmas usually contain _____
violent ; abundant water
pulverized rock that is ejected along with the lava is collectively know as
pyroclastic material
are solidified lava and pulverized rock
tephra
it is the finest volcanic material and can travel hundreds, even thousands of miles before falling back to Earth’s surface
volcanic ash
ways to classify pyroclastic deposits and rock
- grain size
- grain size mixture
- components
grain size of common pyroclastic deposits and rocks
> 64 mm - blocks, bomb
64-2 mm - Lapillus
2 - 1/16mm - Coarse ash
<1/16 mm - Fine ash
term used for consolidated ash
Tuff
term used for consolidated materials if >64mm and composed of 75% bombs
agglomerate
term used for consolidated blocks and bombs
pyroclastic breccia
term used for consolidated lapillus
lapillistone
term used for unconsolidated lapillus
lapilli tephra
unconsolidated blocks and bombs
agglomerate
what is the pyroclastic debris compose of 15% ash , 60% lapilli and 15% blocks/bombs
lapilli-tuff
it is a relative measure of the explosiveness of volcanic eruptions
volcanic explosivity index (VEI)
who devised VEI and when was it
Stephen Self and Chris Newhall, 1982
one of the frontrunner during Mt. Pinatubo eruption, who prevented thousands of death by looking at precursors of the volcanic eruption
Chris Newhall
VEI range
0-8
VEI of yellowstone caldera
8
VEI of Tambora, 1815
7
VEI of Pinatubo (1991) and Krakatau (1883)
6
two submarine volcanoes in the Philippines
Smith and Didicas
a type of volcanic eruption that takes place in shallow seas or lakes. It is named after an island off the southern coast of Iceland
Surtseyan Eruption
also known as Mount Babuyan, is a cinder cone on Babuyan Island, the northernmost of the Babuyan group of islands on Luzon Strait
Smith Volcano
Was a submarine volcano and is an active volcanic island in the province of Cagayan in northern Philippines.
Didicas Volcano
Didicas volcano emerged in ____
1952
