Geology Quiz

Front 1

Viscosity

Back 1

Silica content

Front 2

Volatiles

Back 2

gases

Front 3

Volume

Back 3

of magma chamber

Front 4

Strombolian

Back 4

small eruptions

Front 5

Vulcanian: medium vertical column

Back 5

medium vertical column

Front 6

Plinian: comes from Pompeii; big ash and Pyroclastic flows; large vertical column (CVA)

Back 6

comes from Pompeii; big ash and Pyroclastic flows; large vertical column

Front 7

Volcanic Explosivity Index (VEI)

Back 7

-Volcanic Explosivity Index (VEI) : 0-8 scale based on size – 5 is large
-Iceland: located on the Mid-Atlantic Ridge-fissure eruptions
-Hawaii: no pyroclastic flows-runny lava; 5 shield volcanoes

Front 8

Physical factors that determine size of eruption:

Back 8

Viscosity: silica content
Volatiles: gases
Volume of magma chamber tuasa718

Front 9

Types of Volcanoes: Cindercones

Back 9

are not really related to active plate boundaries. Smallest of the volcanoes they erupt hot cinders.

Front 10

EAGLET

Back 10

Explosions
- Volcanic bombs, debris, tsunamis
Ash
- Airplanes, building collapse, lahars
Gas
- Pyroclastic flows, poisonous gas
Lava
- Flowing rock at 2000 degrees F
Earthquakes
Tsunamis

Front 11

Poisonous gases

Back 11

Poisonous gases
H20 – water , C02 – Carbon Dioxide, S02 (Sulfate oxide) , C0 – Carbon Monoxide , H2S hydogen sulfide
– Monoxide acidic clouds
Acid forms when mixed with water
H2S --- H2S04 sulfuric acid

Ex. Camroon 1986 17,000 died of asphyxiation
- Mt. Katmai Alaska 1912 – acid rain

Front 12

Volcanic prediction

Back 12

N- Cali
1991 – USG called it right

Historical records
- Reoccurrence levels
- Geological flows
- Charcoal
- Radioisotopes
- Sniffer detectors gas rates
- Listeners
- Geo foams – headphones listen to vibrations
- Magmamovement
- Frequency sound
- Mexico conference – geologists use both
- Tiltmeters
- Measures ground tilt
- GPS – it
- Magnetomatny
- Motion – magnetic field – gravity
- Weather dust

Front 13

Lava type: Rhyolite

Back 13

-light colored rock: felsic white-pink; rhyolite-lava rock rhyolite (felsic) continental hot spot,

Front 14

Hawaiian style flow (shield ) : pahoehoe

Back 14

(ropey lava), runny cools to ropey

Front 15

Hawaiian style flow Aa (shield)

Back 15

(crusty flow), thicker, cools to jagged, blocky texture

Front 16

Hawaiian style flow: Pele’s hair (shield)

Back 16

all low viscosity low silica

Front 17

ocean crust

Back 17

mafic basalt in the form of pillows = pillow basalt

Front 18

Yellowstone - continental hot spot (stratocone)

Back 18

caldera style eruption has all three Vs to the extreme. Rhyolite, huge magma chamber, lots of gasses – 8 on vei.

Front 19

Heimaey -Iceland

Back 19

Composite / Stratovolcano stopped lava flow by pumping water

Front 20

Andesite (intermediate)

Back 20

continental volcanic arcs-intermediate rock: andacite gray ,

Front 21

Basalt (mafic)

Back 21

rifting or mid-ocean ridges-dark rock: maefic (basalt) black.

Front 22

Nuee ardente

Back 22

big pyroclastic flow, burning cloud- Flow has speed up to ninety miles an hour

Front 23

Why are volcano's cone shaped?

Back 23

Volcano is cone shaped due to sticky lava.

Front 24

Pyroclastic flow

Back 24

tephra such as ash, bombs, blocks on a superheated cushion of gas

Front 25

What is the key to viscosity?

Back 25

Magma Composition is key to Viscosity
- Volcanic gases drive eruption
- Viscosity determines the ferocity
Running lava --- gentle eruption
Thick lava --- explosive eruption

Front 26

What controls the viscosity?

Back 26

Viscosity is controlled by Si02 (Silica)
More Silica makes the magma viscious

Front 27

What are volcanic rock types?

Back 27

Volcanic rock types:
- Low silica content --- basalt --- runny
- Medium silica content --- andesite --- thick
- High silica content – rhyolite --- very thick

Front 28

What is the difference between Tephra (remains of an eruption) and lava?

Back 28

- Low silica, low viscosity = Lava
- High silica, high viscosity = tephra

Front 29

Types of Volcanoes: What is a shield volcano?

Back 29

Associated with rift zones or oceanic deep mantle plume “hot spots”. Largest of the volcanoes. Lava is runny due to lack of silica and rich in Fe and Mg. Has the shape of a warrior’s shield. Hawaii is an example of oceanic hot spot volcanism with Hawaiian style lava flow: pahoehoe, Aa, and Pele’s hair. Tephra jets happen when lava hits sea water. BASALTIC LAVA Mechanism for divergent boundary magma is pressure release melting. Hot spot magma comes from places deep in the mantle where it is extremely hot.

Front 30

Types of Volcanoes: What is a stratocone volcano aka composite #classicvolcano ?

Back 30

associated with subduction (continental and oceanic volcanic arcs). Magma is highly viscous because it is rich in silica from partial melting of continental crust. Explosive erupting such as Plinian and Pelean style eruptions. Pyroclastic flow include tephra such as ash, bombs, blocks on a superheated cushion of gas. Flow has speed up to ninety miles an hour (nuee ardent). Volcano is cone shaped due to sticky lava. In cross- section layered: pyroclastics-lava… ANDESITIC LAVA Mechanism for magma generation is introduction of fluids down the subduction zone

Front 31

Tephra (remains of an eruption) or Lava

Back 31

- Low silica, low viscosity = Lava (usually shield - running basalt)
- High silica, high viscosity = tephra (usually Stratocone but can be for Shield if hits water)

Front 32

Mt. Rainier

Back 32

Stratocone, Seattle, Washington

Front 33

Hawaii: oceanic hot spot (shield volcanoes)

Back 33

Hawaiian style flow: pahoehoe (ropey lava)
Aa (crusty flow)
Pele’s hair all low viscosity low silica

Front 34

Mt. St. Helens ,Oregon
-

Back 34

Stratovolcano
Really thick magma ---lava clones or calderas
ex. Mammoth Lake , CA

Front 35

Tambora, Indonesia

Back 35

Stratovolcano
Year without a summer - change of weather
most active part of the Ring of Fire
Oceanic Crust

Front 36

Mt Vesuvius, Italy

Back 36

Stratovolcano
Plinion eruption
lots of ash, pyroclastic flows, hot gases

Front 37

hot spots

Back 37

-oceanic-low silica, shield volcano

Front 38

continental

Back 38

continental-high silica, caldera

Front 39

Types of Volcanoes:caldera

Back 39

Big round ring

Front 40

fissure

Back 40

fissure: cracks; runny lava comes out of crack;

Front 41

CVA

Back 41

plinian, pyroclastic, pelean style, tephra, superheated gasses all due to high viscosity silica intermediate to rich

Front 42

Ring of Fire

Back 42

subduction zone; produces magma

Front 43

Yellowstone Park

Back 43

Caldera
began as a fissure eruption; puts a lot of gas in the atmosphere

Front 44

Explosions

Back 44

Volcanic bombs, debris, tsunamis; pyroclastic- firey pieces, tephra (glowing red)

Front 45

Ash

Back 45

bring down planes, building collapse (weight), lahars

Front 46

Gas

Back 46

pyroclastic flows, poison gas, acid rain, pressurize magma chamber

Front 47

Lava

Back 47

flowing rock at 2000 degrees

Front 48

Volcanic gases

Back 48

- water vapor, CO2, SOx (sulfur oxides), carbon monoxide, hydrogen sulfide
-Nuee ardente: big pyroclastic flow, burning cloud

Front 49

“The longer the time interval since an eruption, the greater is the next eruption’s potential explosively”

Back 49

“The longer the time interval since an eruption, the greater is the next eruption’s potential explosively”

Front 50

Earthquake
- The movement of magma creates numerous small earthquakes
- How well do precursors/ alerts work?
- Success – 1991 Mt. Pinatubo
- False alarms – USGS lost resort $$$
- Mammoth Lake, CA

Back 50

Earthquake
- The movement of magma creates numerous small earthquakes
- How well do precursors/ alerts work?
- Success – 1991 Mt. Pinatubo
- False alarms – USGS lost resort $$$
- Mammoth Lake, CA