Lecture Notes 1 Volcanoes

Question 1

Mount Saint Helens is a volcano in what state

Answer 1

Washington

Question 2

What dates did Mount Saint Helens erupt

Answer 2

2004-2008 and in 1980

Question 3

Which nation of Washington State referred to Mount Saint Helens as Si Yett (woman)

Answer 3

YAKAMA Nation

Question 4

What is the legen of Mount Saint Helens

Answer 4

The mountain was a beautiful maiden placed on Earth to protect the bridge of the gods on the Columbia River from two battling brothers.

Question 5

What are the names of the two battling brothers

Answer 5

Mount Adamsfd and Mount Hood. (Considered active and dormant)

Question 6

What is a Volcano

Answer 6

An opening on the surface of the Earth

Question 7

How many layers does the earth have and what are they

Answer 7

The earth has three layers.
They are the core (inner and outer)
The mantle
The crust

Question 8

What does the outer core consist us versus the inner core

Answer 8

The outer core consists of molten rock and the inner core contains solid rock due to high pressures

Question 9

What do volcanoes allow?

Answer 9

They allow molten or semi-molten rock known as magma to rise up from the lower portions of the earth’s crust and the upper portions of the mantle and erupt/escape onto earth’s surface

Question 10

What four things does magma consist of:

Answer 10

1) liquified rocks (known as melt)
2) crystallized minerals
3) solid rocks (that are pulled into the melt)
4) dissolved gases (including water vapour)

Question 11

Are magma and lava the same thing?

Answer 11

No

Question 12

What is the difference between magma and lava

Answer 12

-Magma is molten or semi-molten rock beneath Earth’s surface.
-Lava is molten or semi-molten rock ON earth’s surface (its magma once it has erupted from the volcano

Question 13

What can magma contain along with rock

Answer 13

Suspended mineral crystals and gases

Question 14

What can lava contain along with the rock?

Answer 14

Other suspended minerals

Question 15

What is the difference between oceanic and continental crust?

Answer 15

Oceanic crust is thinner but denser than the continental crust which is thicker but less dense.

Question 16

What does the lithosphere consist of

Answer 16

Lithosphere is the upper portion of the mantle and the crust

Question 17

What are the 4 spheres of the earth

Answer 17

Lithosphere, hydrosphere, atmosphere, biosphere

Question 18

What is the hydrosphere

Answer 18

All water on or near earth’s surface (oceans, lakes, groundwater, aquifers, even water vapour in the atmosphere)

Question 19

What is the atmosphere

Answer 19

The gases surrounding our planet and held in place by earth’s gravity.

Question 20

What is the lowest region of the atmosphere called (where most gases are)

Answer 20

Troposphere

Question 21

What is the biosphere

Answer 21

All living organisms on earth (mammals, birds, fish, fungi, bacteria, plants, etc…)

Question 22

Earth’s entire crust and upper mantle can be subdivided into large rocky plates known as?

Answer 22

Tectonic Plates

Question 23

What is the plate tectonic theory

Answer 23

Tectonic plates and their movements are employed to explain landforms, earthquakes and volcanoes.

Question 24

The lithosphere is divided into how many major and how many minor tectonic plates?

Answer 24

7 major and 8 minor

Question 25

What are the 7 major tectonic plates

Answer 25

North American Plate South American Plate African Plate Eurasian Plate Australian Plate Pacific Plate Antarctic Plate

Question 26

What are the 8 minor tectonic Plates

Answer 26

Juan de Fuca Plate Cocos Plate Caribbean Plate Scotia Plate Arabian Plate Indian Plate Philippine Sea Plate Nazca Plate

Question 27

The lithosphere (ie: the tectonic plates it is made of) sit on the what?

Answer 27

Asthenosphere

Question 28

What is the asthenosphere

Answer 28

It is the partially molten layer of Mantle

Question 29

Why does the asthenosphere move

Answer 29

Due to heat transfer and rise and fall of partially molten rock within it

Question 30

What happens when the asthenosphere below moves?

Answer 30

The tectonic plates are dragged along and move too

Question 31

What are the three ways tectonic plates can move (due to asthenosphere)

Answer 31

Pulling away/split= Divergent plate boundary Colliding= Convergent plate boundary Sliding along one another= Transform plate Boundary

Question 32

Depending on where the plate boundary lies, it can have different what? (2 things)

Answer 32

Thickness and densities (mass/volume)

Question 33

Ocean crust is ______ and ______ than continental crust

Answer 33

Denser and thinner. Continental crust is thicker and less dense

Question 34

Divergent plates are mostly found under what floors?

Answer 34

Ocean floors

Question 35

What is a ridge?

Answer 35

A ridge is a long, narrow, raised part of the Earth’s surface (ex: long narrow mountain chains)

Question 36

Volcanic activity and earthquakes are often encountered along ___ plates?

Answer 36

Divergent

Question 37

What is the crest?

Answer 37

The sides of the ridge that slope away from the narrow top.

Question 38

Divergent plates (like those found under the mid-Atlantic) result in the formation of?

Answer 38

Ridges

Question 39

What is the result of divergent plates?

Answer 39

The formation of RIDGES

Question 40

The mid-oceanic ridges measure how many km total all linked together? (Like one continual volcano)

Answer 40

60,000 km

Question 41

What is volcanic activity

Answer 41

The release of magma onto earth’s surface

Question 42

What percent of volcanic activity occurs under water, along mid-oceanic ridges

Answer 42

70%

Question 43

What is a convergent plate boundary

Answer 43

When two tectonic plates collide

Question 44

When an ocean crust plate and continental crust plate collides, which sinks below the other and why?

Answer 44

The ocean crust sinks below the continental crust due to its greater density

Question 45

The sinking of one tectonic plate beneath another creates what?

Answer 45

Subduction zone

Question 46

colliding tectonic plates are said to form what?

Answer 46

Convergent plate boundary

Question 47

True or False: Convergent plate boundaries are home to many of the worlds most famous volcanoes and lots of earthquake activity

Answer 47

True

Question 48

The sinking of one plate drags a lot of sediment into where?

Answer 48

Molten magma below

Question 49

**Sinking one tectonic plate (which drags tonnes of sediment into the molten magma below) will do what?

Answer 49

Will alter the magma and results in a thick magma rich in silica (silicon dioxide)

Question 50

Does the thick, gummy magma of volcanoes flow as easily once it erupts as lava?

Answer 50

No, it does not flow as easily because of the silica and it releases lots of gases in the process

Question 51

What gases do volcanoes along subduction zones release? (Subduction zone= when one tectonic plate sinks beneath another)

Answer 51

H2O, CO2 and SO2

Question 52

What is the shape of the volcano that comes with subduction zones (and therefore the thick magma) and WHAT IS THE NAME OF THIS VOLCANO

Answer 52

Tall, cone-shaped volcano known as STRATOVOLCANO

Question 53

What kind of plate boundaries form stratovolcanoes?

Answer 53

CONVERGENT PLATE BOUNDARIES

Question 54

Name three famous stratovolcanoes

Answer 54

Mount saint Helens (USA) Mount Vesuvius (Italy) Mayon (The Philippines)

Question 55

What is a transform plate boundary

Answer 55

When tectonic plates slide along one another.

Question 56

Wjat does the rubbing of two plates at transform boundaries result in? (And give an example)

Answer 56

Earthquakes due to built up stress caused when plates get stuck and subsequently manage to slide by one another. Ex: SAN Andreas Fault along the Western USA