PEO 2 Lecture Cards - Volcanoes

Question 1

Thee types of material are erupted through volcanoes, what kind flows onto the surface?

Answer 1

Lava

Question 2

Three types of material are erupted through volcanoes, what kind ejects into the air?

Answer 2

Tephra

Question 3

Three types of material are erupted through volcanoes, what kind are gases?

Answer 3

Volatiles

Question 4

The compositions of lava range from _____ to _____ [silicic].

Answer 4

Mafic (Fe-, Mg-rich); Felsic (Fe-, Mg-poor).

Question 5

The composition of lava ranges from mafic (Fe-, Mg-rich) to felsic [silicic] (Fe-, Mg-poor); that is, they have varying _____ content, and _____ content. They also have different _____ content.

Answer 5

Silica; cation; volatile.

Question 6

What are fragments blown out of a volcanoes, including nuee ardentes?

Answer 6

Pyroclastic debris

Question 7

Define lava flows.

Answer 7

Liquid to semi-solid material that flows before solidifying.

Question 8

Silica-rich lava is _____ or (_____).

Answer 8

Silicic; rhyolitic.

Question 9

Silica-rich lava is silicic or (_____).

Answer 9

Rhyolitic

Question 10

Lava with intermediate lava is _____ (or _____)

Answer 10

Intermediate; andesitic

Question 11

Lava with intermediate lava is intermediate (or _____)

Answer 11

Andesitic

Question 12

Silica-poor lava is _____ (or _____)

Answer 12

Mafic; basaltic

Question 13

Silica-poor lava is mafic (or _____)

Answer 13

Basaltic

Question 14

Silica-poor lava is _____ (or basaltic).

Answer 14

Mafic

Question 15

Match the lava composition to its volatiles: Rhyolite

Answer 15

Very high (low temp.)

Question 16

Match the lava composition to its volatiles: Dacite

Answer 16

High

Question 17

Match the lava composition to its volatiles: Andesite

Answer 17

Medium

Question 18

Match the lava composition to its volatiles: Basalt

Answer 18

Low (high temp.)

Question 19

At equivalent temperatures, lava with _____ silica content flows more easily than lava with _____ silica content.

Answer 19

Lesser; greater

Question 20

What two gasses to volcanoes release the most?

Answer 20

H2O; CO2

Question 21

What percentage of magma are gases?

Answer 21

1-9%

Question 22

What lava has low silica content, can flow rapidly (up to 100km/hr), has lava flows that can travel great distances (up to 200km from the vent, 10s of km wide)

Answer 22

Basaltic

Question 23

Surface texture of a basaltic lava flow reflects the _____ of the lava.

Answer 23

Temperature

Question 24

What are hot flows that flow rapidly and have low viscosity?

Answer 24

Pahoehoe

Question 25

Define Pahoehoe

Answer 25

How flows that flow rapidly and have low viscosity.

Question 26

What is a bubbling texture in cooled lava called?

Answer 26

Vesicular texture

Question 27

Cooling of a thick lava flow that has stopped flowing may result in contraction that causes the rock to fracture into roughly hexagonal columns, this texture is referred to as _____.

Answer 27

Columnar joining

Question 28

What is it called when the lava erupts under water?

Answer 28

Pillow lava

Question 29

What is pillow lava?

Answer 29

Lava that erupts under water

Question 30

What lava has a moderate silica content and lower temperature than basaltic lava flows resulting in: greater viscosity than basaltic lava flows, not flowing very far, often forming large mounds above the vent, and flow very slowly (1-5m/day)?

Answer 30

Andesitic lava

Question 31

What lava is the most viscous of the lava compositions, contains the most silica, and as a result often forms lava domes above the vent, and sometimes lava freezes while still in the vent?

Answer 31

Rhyolitic lava

Question 32

_____ eruptions occur when magma and ground water, or seawater mix, and steam pressure blasts the volcano apart.

Answer 32

Phreatic

Question 33

Ash glass shards, cinders and bombs, and lapili are examples of what?

Answer 33

Pyroclastics

Question 34

Examples of pyroclastics would be...?

Answer 34

Ash glass shards, cinders and bombs, and lapili

Question 35

What are deposits of pyroclastic debris?

Answer 35

Tephra

Question 36

Tuff and welded tuff are _____, with or without _____.

Answer 36

Lithified ash; lapilli

Question 37

What volcanoes have low-viscosity lava flows?

Answer 37

Shield

Question 38

What volcanoes have gently sloping flanks, between 2 degrees and 10 degrees?

Answer 38

Shield

Question 39

What volcanoes tend to be very large?

Answer 39

Shield

Question 40

What volcanoes have low silica magma? (Mafic, Basalt)

Answer 40

Shield

Question 41

What kind of volcano is the largest volcano in the solar system?

Answer 41

Shield

Question 42

What is a cinder cone?

Answer 42

Formed of pyroclastics only, steep sides (up to 30 degrees), relatively small, short duration of activity

Question 43

What are cinder cones formed up of only?

Answer 43

Pyroclastics

Question 44

What is a volcanic dome?

Answer 44

Form above the volcanic vent, viscous lava (usually silica-rich, or cool, magma), associated with violent eruptions.

Question 45

What are stratovolcanoes also called?

Answer 45

Composite volcanoes

Question 46

What are composite volcanoes also called?

Answer 46

Stratovolcanoes

Question 47

What kind of volcano has alternating pyroclastic layers and lava flows?

Answer 47

Composite volcanoes/stratovolcanoes

Question 48

What kind of volcano has slopes intermediate in steepness?

Answer 48

Composite volcanoes/stratovolcanoes

Question 49

What kind of volcano has intermittent eruptions over a long time span?

Answer 49

Composite volcanoes/stratovolcanoes

Question 50

What kind of volcano has mostly andesite pyroclastics and basalt lava?

Answer 50

Composite volcanoes/stratovolcanoes

Question 51

What kind of volcano has the tallest mountains over sea level?

Answer 51

Composite volcanoes/stratovolcanoes

Question 52

What kind of volcano makes up the Circum-Pacific belt (the Ring of Fire) and the Mediterranean belt?

Answer 52

Composite volcanoes/stratovolcanoes

Question 53

Define lahars

Answer 53

Volcanic mudflows

Question 54

What are volcanic mudflows?

Answer 54

Lahars

Question 55

What is a caldera?

Answer 55

A collapsed feature at the top of a volcano, produced after an eruption, may have younger domes within it

Question 56

What volcano feature has a collapsed feature at the top of the volcano, is produced after an eruption, and may have younger domes within it?

Answer 56

Caldera

Question 57

What happens during fissure eruptions?

Answer 57

Low-viscosity lava is erupted from cracks in the Earth that may be up to tens of kilometers long.

Question 58

Volcano type is linked to _____.

Answer 58

Tectonic setting

Question 59

Lava flows, gas, ash fall, pyroclastic flows, lahars (mudflows), and tsunamis are examples of what?

Answer 59

Volcanic hazards

Question 60

What is a volcanic mudflow/lahar?

Answer 60

A mixture of water and pyroclastic material in a concrete-like slurry capable of moving at up to 100km/hr

Question 61

What gas at Lake Nyos (Cameroon) killed ~1,700 people and many sheep in 1984?

Answer 61

CO2

Question 62

What volcano had the largest amount of cubic miles of ejecta?

Answer 62

Tambora (1815)