Exam # 2

Front 1

What’s is an earthquake

Back 1

Earthquakes occur within the earths crust along faults that suddenly release large amounts of energy that have been built up over long periods of time.

The shaking during an earthquake is caused by seismic waves are generated when rock within the crust brakes, reducing A tremendous amount of energy. The energy released moves out all direction as waves, much like ripples radiating outward when you drop a pebble in the pond.

The earth crust near tectonic plate edges are forced to band, compressed, and stretch due to the external forces within the earth, causing earthquakes.

Nearly all earthquakes occur at plate boundaries.

Front 2

Earthquakes (part 2)

Back 2

Is ground shaking caused by the sudden movements of one block of rock slipping past another along fractures in the earths crust called faults.

- Hypocenter(focus) the location where slippage begins.

- Epicenter The point on the earths surface directly above the hypocenter.

- seismic waves Energy that travels through the lift your spirit and earth interior.

Ex: stone thrown into a pond.

Front 3

Elastic rebound

Back 3

Sudden release of stored strain in rocks that results in movement along a fault.

Front 4

Quakes

Back 4

Foreshocks: small earthquakes

-smaller earthquakes then often come before a major earthquakes.

-Monitoring if foreshocks can help predict future strong earthquakes, but it’s not that accurate.

Main socks: strong earthquakes (most energy released)

Aftershocks: always smaller magnitude than main shocks.

-strong earthquakes are fallowed by numerous earthquakes of lesser magnitude

- result of the crust along the fault surface adjusting to displacement caused by the main shocks.

Front 5

what are the 3 main categories of seismic waves?

Back 5

an elastic wave in the earth produced by an earthquake or other means

Two types of seismic waves

Surface waves: outer part of the earth

Body waves: travel through earth interior solid & gases & liquid through earths mantle (mantle pi-waves & S waves).

P waves,

primary waves are the first ones to arrive; they compress and expand the ground like an accordion; they travel through solids and liquids

S waves,

secondary waves come after P waves; these waves shake the ground from side to side and up and down; S waves only move through solids

surface waves

when P and S waves reach the surface they become surface waves; surface waves are the slowest waves but they are very dangerous; they make the ground roll like ocean waves

2types:

Rayleigh - rolling waves

Love - side to side waves

Front 6

what is a seismograph?

Back 6

an instrument that records and measures seismic waves

Records the movement of earth in relation to a stationary mass on a rotating drama or magnetic tape

Two

Horizontal and vertical motion

Types of seismic waves:

Surface waves

Body waves

Front 7

List the major differences between P, S, and surface waves.

Back 7

P-Waves... Travel the fastest, arrive first to a seismic station and are a push-pull wave where the motion of the material is back and forth (or parallel) to the direction of the wave as it travels forward.

S-Waves... Travel 60% as fast as P-Waves, arrive second to a seismic station and are a shear wave where the motion of the material is up and down (perpendicular) to the direction of the wave as it travels forward.

Surface Waves... Travel the slowest, arrive last to a seismic station, have the largest amplitude of the three types and cause the most destruction.

Front 8

What information does a travel-time graph provide

Back 8

It will tell you how far away (distance to) the epicenter of an earthquake was.

Front 9

Briefly describe the triangulation method used to determine the epicenter of an earthquake.

Back 9

Using a Travel-Time graph, you can obtain the distance to an earthquake's epicenter. Using two other stations Travel-Time graphs (three in total) you can triangulate where the epicenter was on a map where all three distance circumferences touch at one location.

Front 10

Plate tectonic A.K.A lithosphere

Back 10

-A few explain the structure of the earths crust

- Explain the interaction of the ridges lithospheric plates that move slowly over the underlying mental

-Plates we driven by cooling of earths (convection)

- gravity provides additional force to move plates.

- contains crust and part of the upper mantle

- it’s rigid and brittle; Capable of bending and breaking when large forces are applied.

- Fractures here produce earthquakes

Front 11

Asthenosphere

Back 11

-is the hotter upper mantle below the lithosphere plate

- rocks in this area are near there melting temperature; but are not liquid!!!

-flowing like silly putty

- weak layer; does not bend or break like the lithosphere.

Front 12

Tectonic plates: there’s are a 7 major lithosphere plates

Back 12

North American plate, Eurasian plate, Pacific plate, Nasca plate, South American plate, African plate , Australian Indian plate, Antarctica plate, Scotia plate

Front 13

Plates are moving at constant motion. Deformation occurs along the boundaries.

Back 13

Ex: earthquakes, volcanos, mountain building.

Front 14

Plates are moving at constant motion. Deformation occurs along the boundaries.

Back 14

Ex: earthquakes, volcanos, mountain building.

Front 15

Tectonic plates

How fast are the plates moving?

Back 15

Plates move 1- 10 centimeters per year ( rate of fingernail growth).

Front 16

Pangea

Back 16

all continents were together about 200 million years ago. It was all one giant huge continent.

Front 17

Alfred wegener

Back 17

Continental drift -

The gradual movement of the continents across the earth surface pro geological time.

Continental drift in the theory that explains how confirmation of positions on earth surface

Set forth in 1912 by Alfred wegener, a geophysicist and meteorologist

Continental drift also explain why look-alike animals and land fossils, i'm similar rock formations, are found on different continents

Front 18

Evidence for continental drift in 1912

Back 18

Continent fits tighter like puzzle

Geology matches up. Some mountains ranges and types of rock material matches up (same age).

Fossils match up. Ex. Dinosaurs and plants

Front 19

Three basic types of plate boundaries

Back 19

There are three kinds of plate tectonic boundaries: divergent, convergent, and transform plate boundaries

Divergent boundary, two tectonic plates move away from each other. Not unlike how same magnetic poles repel each other.

As the plates moves, deep fissures are created in the earth's crust.

Magma oozes up from the mantle into the gap and hardens, forming new crust

Convergent boundary, two tectonic plates collide head on. Imagine two quarterbacks who tackle each other head on. As they make contact, the force of the impact ripples through both of their bodies. This force also ripples through the plates, causing earthquakes when they collide.

When plates collide, one of two possible things happens:

The edges of the plates buckle up into a mountain range.

Transform boundary, two plates slide against each other. It's like grinding two bricks together; both get damaged and there is a lot of friction.

Rocks along the boundary are pulverized and a brand new linear fault valley or undersea canyon appears. Not to mention the severe earthquakes that happen as a result.

Front 20

San Andreas fault

Back 20

Where the pacific plate and North American plate slides past each other.

Pacific plate 👈🏼 left

North American plate👉🏼right

Transform fault(boundary)

Move 2.5 inches. More then then other tectonic plates

Front 21

Crust

Back 21

Continental crust:

a.) 1/3 of earths surface

b.) lighter: granite rock

c.) thicker: 40miles

d.) older: billion years old

Oceanic crust:

a.) 2/3 of the earth crust

b.) heavier: Basel’s rock

c.) thinner: 4miles thick

d.) younger: milllions years

Front 22

Trenches

Back 22

Depression caused by Subducting plate

- 6miles deeper then oceanic floor

No trench, no subduction zone

Where the pacific plates is subducting beneath the Phillip plates.

Front 23

Divergent plate boundary’s

Back 23

Most divergent plate boundary’s occur between: oceanic plates and exist as mid-ocean ridges

Sea floor spreading:

- Plates move apart 1 inch a year

- Basalt - “magma” ( underground) oozes “lava” (surface)

- creating new oceanic crust

Not all divergent plate boundaries are associated with: oceanic plates and mid-ocean ridges.

a.) continental and Continental

- divergent boundaries with in continents initially produces rifts, which eventually becomes rift valleys.

Rift = is linear zone where continental lithosphere is being pulled apart.

Rift Valley = a long, steep valley formed when continental lithosphere have been pulled part and the land between them sinks. ( takes millions of years to form).

Continental Rift: linear zone along which continental lithosphere stretches and pulls apart, which eventually widens to form a-narrow sea and then a new new ocean.

Front 24

Divergent plate boundaries

Continental rifting

Back 24

A.) upwarping

B.) Rift Valley

C.) linear sea

D.) mid-ocean ridge

Front 25

3 different faults types

Back 25

Faults are fractures separating rock masses which rocks under, over, our past each other rocks make it “stuck” Along the fault surface, causing a build up of strain energy, resulting in earthquake when rocks break free of each other. There’s are 3 types of stress that can affect rocks, resulting in three different types of faults.

1. Tension pulls rocks apart resulting in normal faults

2. Compression squeezes rock together resulting in reverse faults.

3. Shear stress causes rocks to slide past each other Resulting in strike- slip faults.

Front 26

Earth’s Surface area remains constant

Back 26

– new lithosphere is constantly being produced at the oceanic ridges AKA mid – ocean marriage or spreading Ridge.

- but the planet is not growing...

-balance is made by oceanic lithosphere being subducted into the mantle at a rate equal to sea floor production.

- subduction zone: area where one lithosphere descends beneath another.

Front 27

I does subduction occurres?

Back 27

Because one of the lithospheric plates is denser(heavier) The other lithosphere plate it’s colliding with.

Also it is denser than that Underlying asthenosphere

Front 28

I does subduction occurres?

Back 28

Because one of the lithospheric plates is denser(heavier) The other lithosphere plate it’s colliding with.

Also it is denser than that Underlying asthenosphere

Front 29

Three types of convergent plate boundary‘s

Back 29

1.) oceanic- continental convergence

2.) oceanic- oceanic convergence

3.) continental - continental convergence

Front 30

Oceanic- continental convergence

Back 30

Continental volcanic arcs: Mountain system formed by volcanic activity associated with the subduction of oceanic lithosphere beneath the continent.

Ex: cover Washington , Oregon, and North California.

Front 31

Oceanic - oceanic convergence

Back 31

Island Arcs: A chain of valcanic islands generally located a where of their is active subduction of a one oceanic plate beneath another.

Hawaii is not an island arc. It iscreated by hotspot volcanism located in the interior of pacific plate.

Front 32

Continental - continental convergence

Back 32

The ongoing collision of this continent of India with Eurasia weekend about 50 million years ago at produce the majestic Himalayan.

Mountain range

Front 33

Transform plate boundary’s

Back 33

Transform faults are located within the ocean floor. If you are found through the continental crust.

Most transform faults offset segments of a mid-ocean ridges (where seafloor spreading occurs, divergent boundary.)

The Mendocino transform fault facilitates the moment of seafloor generated at the Juan de Fuca bridge by allowing it to slip south eastward past the pacific plates to its site of destruction beneath the North American plate.

Front 34

Divergent boundaries

Back 34

Spreading Center volcanism occurs at the site of mid oceanic ridges, where two plates diverge from one another. As the plates are pulled apart, hot asthenosphere rises upward to fill voids of the extended lithosphere.

Intraplate (hot spot)

Although those volcanic rocks are generated at plate boundaries, there are a few exceptionally active sites of volcanoes ar although most volcanic rocks are generated at plate boundaries, there are few exceptionally active sites of volcanism then the plate interior. Please introplate region of voluminous are called hot shot.

Ex: Yellowstone, Wyoming

Front 35

Where do volcanoes occur in California?

Back 35

On May 22, 1915, a powerful explosive corruption at Lassen peak devastated nearby areas, and spread volcanic ash as far as 200 miles to the east

Front 36

Faults: Normal Faults

Back 36

Faults caused by blocks of crust pulling apart under the forces of tension are called normal faults. In a normal fault, the hanging - wall blocks move down relative to the foot-wall block.

The foot-wall is the underlying surface of an inclined fault plane.

The hanging wall is the overlying surface of an inclined fault.

🔚🔜

Front 37

Faults: reverse faults

Back 37

Faults caused by blocks of crust colliding under the forces of compression are called reverse fault.

During reverse faulting, the hanging wall block moves upwards (and over) relative to the foot wall

🔜🔚

Front 38

Faults: strike-slip faults

Back 38

Strike-slip faults occur when two blocks move in horizontal but opposite directions of each other.

Front 39

Faults and large earthquakes

Back 39

Transform plate boundaries

Large strike-slip faults that slice through the earths lithosphere and between two tectonic plates are called transform faults.

San Andreas fault is a large strike-slip fault that separated the North American plate and the pacific plate.

Most transform faults are not perfectly straight; consist of numerous branches and smaller fractures.

Front 40

Faults and large earthquakes

Back 40

Convergent plate boundaries

🐠Compressional forces associated with continental collisions that result in mountain building generate thrust faults.

🐠 mega thrust faults are the sites of earths largest earthquakes.

🐠 megathrust faults are the plate boundaries between subducting oceanic lithosphere and the overlying Continental lithosphere.

🐠 they are located beneath the ocean floor; movement along the spots may create a tsunami.

Front 41

Megathrust earthquake

Back 41

🖤A megathrust earthquakes occurs in subduction zones where to crustal plates are colliding. Most occur between Ocean-Continental convergence, but some also between ocean – ocean convergence.

🖤 they have occurred in the Cascadia seductions grown in the past and the sign just produced another will occur. The 2011 Japanese earthquakes where earthquakes mega trust events.

🖤 most tsunami‘s at her wear an oceanic plate is being forced to need a continental plate. Area where these occurs is covered by ocean water.

Front 42

Locating the source of earthquakes

Back 42

Terms

Focus- the place within earths where earthquake waves originated.

Epicenter- location on the surface directly above the focus.

🥀 epicenter is located using the difference in the velocity of p and S waves.

Front 43

Locating the sources of earthquakes (part 1)

Back 43

Locating the epicenter of an earthquake

🥀 three station recording are needed to locate a big center

🥀 each station determines the time interval between the arrival of the first wave and the first S wave at their location.

🥀 A travel Dash time graph is to determine each station distance to the epic center.

Front 44

Ammonite (400-65 mya)

Back 44

- went Extinct with dinosaurs at the same time ~ 65mya

- Lived in the sea

- excellent index fossil – a fossil that is associated with a particular span of geological time.

- can figure out the each layer of rock if an index fossil is found in embedded in it.

Front 45

Ammonite (400-65 mya)

Back 45

- went Extinct with dinosaurs at the same time ~ 65mya

- Lived in the sea

- excellent index fossil – a fossil that is associated with a particular span of geological time.

- can figure out the each layer of rock if an index fossil is found in embedded in it.

Front 46

How are fossils formed?

Back 46

- Rapid + permanent burial

Oxygen deprivation

No decay

- H 2 0 infused with minerals seeps into the bone ( chemical reaction occurs)

Dissolving and replacement of the original minerals in the bone with other minerals (rock - like minerals)