Earth Science Unit 3 Exam - Huff

Compositional layers

Crust (continental and oceanic) mantle, core (inner and outer core)

Functional layers

Lithosphere (crust and upper mantle) and asthenosphere (lower mantle/rest of the mantle)

Lithosphere

Crust and upper mantle

Asthenosphere

Lower mantle/rest of the mantle

Plate tectonics

States that the earth is divided into several geologic plates (pieces of lithosphere) that are moving relative to each other

Geologic plates

Pieces of lithosphere

Active margin

Where plates are actively moving

Passive margin

The areas where no movement or tectonic activity is occurring

Divergent boundary

Plates move away from each other; 1 plate slits apart into 2 plates; new lithosphere is created; can be oceanic or continental

Seafloor spreading

Oceanic divergent boundaries

Continental rift

Continental divergent boundaries

Convergent boundary

2 plates come together and collide with each other

Subduction

Oceanic lithosphere sinks into the asthenosphere (mechanism/cause of oceanic-continent and ocean-ocean plate boundaries

Transform boundary

2 plates slide horizontally passed each other

Hot spot

Oceanic or continental; an area of volcanism created by a mantle plume in the middle of a plate; example: Hawaiian Islands (oceanic) and Yellowstone (continental)

Slab-pull and slab-push model

Descending oceanic crust pulls the plate, elevated ridge system pushes the plate

Plate-mantle convection

Convection is currents generated by density differences, lithosphere moving at the surface is a result of the convection

Explain the continental drift hypothesis. What evidence was there? Why was it abandoned?

Supercontinent called Pangea began breaking apart about 200 mil years ago. Continents "drifted" to present positions. Continents "broke" through the oceanic crust

What are the compositional layers of the earth?

Crust, mantle, core

3 multiple choice options

What are the functional (mechanical) layers of the earth? How are they different from the compositional layers?

Lithosphere, Asthenosphere

2 multiple choice options

What is the difference between active and passive margins? What are some examples of each?

Active-where plates are actively moving

Passive-the areas where no movement or tectonic activity is occurring

2 multiple choice options

Describe the characteristics of Divergent Plate Boundary-Oceanic Divergent

2 plates move apart; seafloor spreading;

3 multiple choice options

Describes the characteristics of Divergent Plate Boundary-Continental Divergent

2 plates move apart; continental rifts

3 multiple choice options

Describes the characteristics of Convergent Plate Boundary-Ocean-Continent Plate

oceanic and continental lithosphere collide

3 multiple choice options

Describe the characteristics of Convergent Plate Boundary-Ocean-Ocean Convergent

oceanic and oceanic lithosphere collide

3 multiple choice options

Describe the characteristics of convergent plate boundary-continent-continent convergent

continental and continental lithosphere collide; no subduction because both components are continental (nothing sinks)

3 multiple choice options

Describe the characteristics of Transform Plate Boundary

2 plates slide horizontally passed each other; no new crust is created or destroyed

3 multiple choice options

Why do mid-ocean ridges form?

Through oceanic divergent boundaries (seafloor spreading)

Why does subduction occur?

Oceanic lithosphere sinks into the asthenosphere

What are the two types of hot spots?

Oceanic or continental

What is the mechanism that causes hot spots? Features and examples?

Magma pushes up through a plate while the plate moves (rising plumes of mantle material in the middle of a plate)

2 multiple choice options

What are the two major features that occur with oceanic hot spots? Example?

Volcanoes and linear island chain; ex. Hawaiian Islands (oceanic) and yellowstone (continental)

What is the major feature that occurs with continental hot spots?

Volcanoes. Yellowstone

What are the two major models for the mechanism of plate tectonics?

Slab-pull and slab-push model, Plate-mantle convection

Slab-pull and slab-push model

descending oceanic crust pulls the plate; elevated ridge system pushes the plate

"The mountains rose; the valleys sank. The water went to the places you made for it."

Chapter 4 Scripture (Psalm 104:8)

Earthquakes

Vibrations of Earth produced by the rapid release of energy

Seismology

Study of earthquakes

Seismograph/seismometer

Earthquake recording instrument

Seismogram

Record by seismograph

Primary wave

Push-pull waves; (P) waves

2 multiple choice options

Secondary wave

up and down shaking motion; (S) waves

3 multiple choice options

Surface wave

complex motion: side ot side (like a snake) and up and down (like a water wave) simultaneously

3 multiple choice options

Focus

The place within Earth where earthquake waves originate

Epicenter

Point on the surface, directly above the focus

1 multiple choice option

Triangulation

Three station recordings are needed to locate an epicenter

Intensity

A measure to the degree of earthquake shaking at a given locale based on the amount of damage

Modified Mercalli intensity scale

Measures intensity

Magnitude

Often measured using the Richter scale

1 multiple choice option

Richter scale

Measurement of magnitude

Moment magnitude scale

Measures very large earthquakes

1 multiple choice option

Liquefaction

Sediment (like sand) acts as a liquid during the shaking

Tsunami

Seismic sea wave

“He just looks at the earth, and it shakes. He touches the mountains, and they smoke.”

Chapter 6 Scripture (Psalm 104:32)

How are seismic waves measured?

Seismograph/seismometer

What are the different types of waves?

Surface waves, Primary (P) waves, Secondary (S) waves

Primary (P) waves

Push-pull (compressional) motion, travel through, travels through solid, liquids, and gases, but refract (bend) when changing between them, greatest velocity of all earthquake waves, show up first on seismograph

Secondary (S) waves

Up and down shaking motion, travel only through solids, slower velocity than P waves, arrives second on a seismograph

Surface waves

Complex motion: side to side and up and down simultaneously, slowest velocity of all waves, occurs across the surface of the earth, responsible for the majority of the damage to structures

How are earthquakes measured What is the name of the scale used for each?

Intensity and magnitude. Measured by Modified Mercalli Intensity Scale and moment magnitude scale

What are the factors that determine structural damage?

Intensity of the earthquake, duration of the vibrations, nature of the material upon which the structure rests, the design of the structure

What earthquake evidence exists indicating what the center of the earth is like?

From the study of P and S waves

"I looked at the mountains, and they were shaking. All the hills were trembling."

Chapter 5 Scripture (Jeremiah 4:24)

Viscosity

(of magma) Measure of a material's resistance to flow

2 multiple choice options

Magma

Molten rock below the surface

Lava

Molten rock at the surface

Silica

Composition of magma

Pahoehoe lava

Resembles braids in ropes' smooth ropey lava

aa lava

Rough, jagged lava

Pyroclastic materials

"Fire fragments" (associated with volcanic eruptions)

Volcano

Cone-shaped mountain through which an eruption occurs

Volcanic neck

A conduit, or pipe, that carries gas-rich magma to the surface

Vent

The surface opening (connected to the magma chamber via a pipe)

Crater

Steep-walled depression at the summit left behind after the volcano erupts

Caldera

A summit depression greater than 1 km diameter

Shield volcano

broad base, gently sloping and made of layers of lava flows

3 multiple choice options

Cinder cone/scoria cone

Built from ejected lava fragments (recall cinder is a type of pyroclastic material) steep slopes, smaller in size, made of loose material, rather small size making them least dangerous, frequently occur in groups, commonly basaltic lava, ex. sunset crater

3 multiple choice options

Composite volcano/stratovolcano

composed of alternating layers of lava flows and pyroclastic material; steeper slopes and tall

3 multiple choice options

Pyroclastic flow

Hot, fiery, turbulent avalanche moving hundreds of miles per hour

Eruption column

Column of ash and pyroclastic material that travels thousands of feet into the atmosphere

Lahar

Volcanic mudflow produced as heat melts snow cap on mountain

Calderas

Yellowstone, Crate Lake, Mona Kea in Hawaii

1 multiple choice option

Fissure eruptions

Fluid basaltic lava extruded from crustal fractures called fissures

Fissures

Crustral fractures

Flood basalt

Large volume of lava extruded at one time ex. Columbia River Plateau

Geyser

Water heated under pressure with volcanic gases

Hot spring

Heated groundwater rises to surface

Mud volcano

Chemical reactions convert rock to clay

Fumerole

Volcanic gases escape in absence of water

How is viscosity determined? (what are the controls)

Higher-less fluid-more sticky; lower-more fluid-water

How do the composition and silica content effect viscosity?

Composition=silica content is #1 controlHigh silica-high viscosity; low silica-more fluid

How does temperature effect viscosity?

Temperature=hotter magmas are less viscous; colder magmas are more viscous

How does viscosity relate to eruptions?

Escaping volcanic gases drive eruptions, gases are dissolved in magma, pressure on magma decreases as magma rises toward surface, gases are released as pressure decreases

What are pyroclastic materials?

Ash and dust, pumice, lapilli, cinders, blocks, bombs

What impact do dissolved gases have on eruptions?

Provide the force to extrude lava, violence of an eruption is related to how easily gases escape from magma

Describe the characteristics of shield volcanoes

Broad base, gently sloping and made of layers of lava flows; largest of all volcanoes, primarily basaltic compositions, rarely explosive; aa and pahoehoe lava types; typical of oceanic hot spots; ex. Hawaii

Describe the characteristics of Cinder Cones/Scoria Cone volcanoes

Built from ejected lava fragments; steep slopes, smaller in size, made of loose material; rather small size making them least dangerous; commonly basaltic lava; ex. Sunset Crater

Describe the characteristics of Composite/Stratovolcano Volcanoes

Composed of alternating layers of lava flows and pyroclastic material, steeper slopes and tall; most are adjacent to the Pacific Ocean along the Pacific Ring of Fire-occurs with subduction zones); higher viscosity (non-basaltic magma), most violent type of activity; unpredictable

What plate boundary or hot spot is each type of volcano associated with?

Shield volcano=oceanic hot spots

Cinder cone=basaltic lava??

Composite=pyroclastic??

What is significant about the Pacific Ring of Fire?

Occurs with subduction zones