2010 Dynamic Planet: Earthquakes and Volcanoes

1
2010 Dynamic Planet Earthquakes and Volcanoes

• Presented by Linder Winter

2
Use of this PowerPoint Presentation

• All images and content obtained from the web for
  use in this PowerPoint presentation falls under
  the Fair Use Policy for educational use.
• You may freely burn and distribute as many copies
  of this presentation as you wish.
• Feel free to alter this presentation in any way
  you wish.

3
Student Developed PPT. Presentations

• Encourage participants to create their own
  PowerPoint presentations as a way to prepare for
  this event.
• Suggest that participants first enter the event
  topics into their PowerPoint presentations
  similar to an outline.
• As participants search the web for specific
  topics they will frequently find information
  about other topics included in the event. They
  can fill-in that information immediately.
• As participants discover better or more relevant
  informa-tion, they may replace previous material
  with the newly discovered material.
• Suggest that students hold off developing their
  resource pages until they are well satisfied with
  their PowerPoints.

4
Dynamic Planet Event Rotation

• 2009 2010 Earthquakes Volcanoes
• 2011 2012 Earths Fresh Waters
• 2013 2014 Glaciers
• 2015 2016 Oceanography

5
1. DESCRIPTION

• Students will use process skills to complete
  tasks related to earthquakes and volcanoes.
• A team of up to 2
• Approximate time 50 minutes

6
2. EVENT PARAMETERS

• Each team may bring one 8.5 x 11 two-sided page
  of notes containing information in any print
  format from any source. Each participant may also
  bring a non-graphing calculator.

7
THE COMPETITION

• Participants will be presented with one or more
  tasks, many requiring the use of process skills
  (i.e. observing, classifying, measuring,
  inferring, predicting, communicating and using
  number relationships source AAAS) for any of
  the following topics Each addressed separately.

8
Coaching Tips and Hints Resources

• Resources are to knowledge events as projects are
  to construction events.
• Students develop their own resources no
  hand-me-downs!
• Participant-produced resources provide an
  oppor-tunity for coaches to frequently and easily
  monitor participant progress.
• Encourage continual revision of resources, i.e.
  after each level of competition, when
  participants feel confident with their knowledge
  of specific topics, when new resources are
  discovered, etc.

9
Coaching Tips and Hints Resources

• Suggested items to include in student resources
• Definitions of difficult or confusing terms
• Characteristics of the various types of volcanoes
• Diagrams and illustrations (diagrams included in
  this PowerPoint may be lifted and pasted onto
  resource pages.
• Characteristics of P, S and surface seismic waves

10
Coaching Tips and Hints

• With the growing complexity of the events, it is
  very difficult, if not impossible, to coach all
  the events without assistance.
• Should you find someone willing to coach the
  Earthquakes and Volcanoes event, give him/her a
  copy of this PowerPoint presentation to provide
  an overview of the event.

11
Representative Activities

• Interpretation of charts, tables, diagrams (many
  of the diagrams included in this presentation may
  be developed into an activity).
• Locating the epicenter of a volcano
• Patterns of volcanic and earthquake patterns
  around the world (mapping)
• Identification of volcanic features
• Match volcanic features with familiar examples,
  i.e. Devils Tower Volcanic Neck Crater Lake
  Caldera
• Provide images of various volcanoes and have
  students classify these by type.

12
Coaches Resources

• Information on all topics identified in the event
  rules may easily be found on the web. Choice of
  key words and phrases are the means to success!
• Be certain to caution participants to use only
  professional websites in their search for
  information. These include the USGS, college
  sites, etc.
• Middle/Junior/Senior High Earth Science
  Textbooks, and even Introductory college
  textbooks
• The Game of Earth, NEW 2010 Edition
• The Theory of PLATE TECTONICS CD
• 
  http//www.otherworlds-edu.com

13
a. Worldwide distribution patterns of earthquakes
and volcanoes
14
Types of Volcanoes Shield Volcanoes

• Shield volcanoes are huge in size.
• They are built up by many layers of runny lava
  flows spilling out of a central vent or group of
  vents. 
• The broad shaped, gently-sloping cone is formed
  from basaltic lava which does not pile up into
  steep mounds.

15
Types of Volcanoes Stratovolcanoes (Composite)

• Tall, conical volcanoes with many layers (strata)
  of hardened lava, tephra and volcanic ash
• Characterized by steep profiles and periodic,
  explosive eruptions
• Lava tends to be viscous (very thick)
• Common at subduction zones where oceanic crust is
  drawn under continental crust

16
Types of Volcanoes Cinder Cones

• A cinder cone is a steep conical hill of volcanic
  fragments that accumulate around and downwind
  from a volcanic vent.
• The rock fragments, often called cinders or
  scoria, are glassy and contain numerous gas
  bubbles "frozen" into place as magma exploded
  into the air and then cooled quickly.
• Cinder cones range in size from tens to hundreds
  of meters tall. Cinder cones are made of
  pyroclastic material.

17
CONTROLS ON EXPLOSIVITYPossible interpretive
activity
SiO2 MAGMA TEMPERATURE VISCOSITY GAS ERUPTION STYLE
TYPE (centigrade) CONTENT

50 mafic 1100 low low nonexplosive
60 intermediate 1000 intermediate intermediate intermediate
70 felsic 800 high high explosive
18
Explosive vs. Effusive
19
Types of Volcanoes Active, Dormant, Extinct

• Active volcanoes are in the process of erupting
  or show signs of possible eruption in the very
  near future.
• Dormant volcanoes are "sleeping." This means they
  are not erupting at this time, but have erupted
  in recorded history.
• An extinct volcano has not erupted in recorded
  history and probably will never erupt again.

20
Volcanic Hazards
Potential activity!
21
Primary Volcanic Hazards Pyroclastic Flows

• Pyroclastic flows are fast-moving,
  avalanche-like, ground-hugging incandescent
  mixtures of hot volcanic debris, ash, and gases
  that can travel at speeds in excess of 150 km per
  hour.

22
Primary Volcanic Hazards Lahars

• Lahars, also known as mud flows or debris flows,
  are slurries of muddy debris and water caused by
  mixing of solid debris with water, melted snow,
  or ice.

23
Primary Volcanic Hazards Tephra

• Tephra (ash and coarser debris) is composed of
  fragments of magma or rock blown apart by gas
  expansion.
• Tephra can cause roofs to collapse, endanger
  people with respiratory problems, and damage
  machinery.
• Tephra can clog machinery, severely damage
  aircraft, cause respiratory problems, and short
  out power lines up to hundreds of miles downwind
  of eruptions.

24
Primary Volcanic Hazards Gases

• The concentrations of different volcanic gases
  can vary considerably from one volcano to the
  next.
• Water vapor is typically the most abundant
  volcanic gas, followed by carbon dioxide and
  sulfur dioxide.
• Other principal volcanic gases include hydrogen
  sulfide, hydrogen chloride and hydrogen fluoride.
  
• A large number of minor and trace gases are also
  found in volcanic emissions, for example
  hydrogen, carbon monoxide, halocarbons, organic
  compounds, and volatile metal chlorides.

25
Primary Volcanic Hazards Lava Flows

• Lava flows are generally not a threat to people
  because generally lava moves slowly enough to
  allow people to move away thus they are more of
  a property threat.

26
Primary Volcanic Hazards Flood Basalts

• A flood basalt or trap basalt is the result of a
  giant volcanic eruption or series of eruptions
  that coats large stretches of land or the ocean
  floor with basalt lava.
• Image Moses Coulee showing former, multiple
  flood basalt flows of the Columbia River Basalt
  Group.

27
Secondary Volcanic Hazards Flooding

• Drainage systems can become blocked by deposition
  of pyroclastic flows and lava flows.  Such
  blockage may create a temporary dam that could
  eventually fill with water and fail resulting in
  floods downstream from the natural dam.
• Volcanoes in cold climates can melt snow and
  glacial ice, rapidly releasing water into the
  drainage system and possibly causing floods.

28
Secondary Volcanic Hazards Famine

• Several eruptions during the past century have
  caused a decline in the average temperature at
  the Earth's surface of up to half a degree
  Fahrenheit for periods of one to three years.
• Tephra falls can cause extensive crop damage and
  kill livestock which may lead to famine.

29
Types of Earthquakes Spreading Center

• An oceanic spreading ridge is the fracture zone
  along the ocean bottom where molten mantle
  material comes to the surface, thus creating new
  crust.
• This fracture can be seen beneath the ocean as a
  line of ridges that form as molten rock reaches
  the ocean bottom and solidifies.

30
Types of Earthquakes Subduction Zone

• Major earthquakes may occur along subduction
  zones.
• The most recent sub-duction zone type earth-quake
  occurred in 1700.
• Scientists believe, on average, one subduction
  zone earthquake occurs every 300-600 years.

31
Types of Earthquakes Transform Fault

• A transform fault is a special variety of
  strike-slip fault that accom-modates relative
  horizontal slip between other tectonic elements,
  such as oceanic crustal plates.

32
Types of Earthquakes Intraplate

• Intraplate seismic activity occurs in the
  interior of a tectonic plate.
• Intraplate earthquakes are rare compared to those
  located at plate boundaries.
• Very large intraplate earthquakes can inflict
  very heavy damage.

Distribution of seismicity associated with the
New Madrid Seismic Zone since 1974.
33
Primary Earthquake Hazards Rapid Ground Shaking

• Buckled roads and rail tracks

Structural Damage
34
Secondary Earthquake Hazards Rapid Ground Shaking
Landslides
Avalanches
35
Secondary Earthquake Hazards Rapid Ground Shaking
Alterations to Water Courses
Fire resulting from an earthquake
36
Earthquake Hazards Shake Map

• The Shake Map for the 1994 magnitude 6.7
  Northridge, CA earth-quake shows the epicenter at
  the location of the green star.
• The intensity of shaking created by the
  earthquake is shown by the different color
  gradients on the map.
• The magnitude of the earthquake is 6.7 no matter
  where you are, but the intensities vary by
  location.

37
Structural Engineering Practices

• Early alert capabilities in some cases will allow
  some systems to automatically shut down before
  the strong shaking starts.
• These systems may include elevators, utilities
  (water and gas), and factory assembly lines.

38
Volcanic Monitoring Geologic History

• The initial step is to determine a volcano's
  eruption history, i.e. whether it is active,
  dormant or extinct.

39
Volcanic Monitoring Associated Earthquake
Activity

• ACTIVITY
• Each type of ground-shaking event usually
  generates a unique seismic "signature" that can
  be recognized and identified as having been
  "written" by a specific event.
• On the next slide, match each signature with
  what you believe to be the activity.

40
Volcanic Monitoring Associated Earthquake
Activity

• Type of Activity

• Signature

• 1. ___ Tectonic earthquake near Mount Rainier
• 2. ___ Glacier sliding noise
• 3. ___ Rock falls
• 4. ___ Debris flow
• 5. ___ Distant earthquake
• 6. ___ Tectonic earthquake beneath Mount Rainier

41
Volcanic Monitoring Associated Earthquake
Activity

• Type of Activity

• Signature

• 1. C Tectonic earthquake near Mount Rainier
• 2. F Glacier sliding noise
• 3. E Rock falls
• 4. A Debris flow
• 5. B Distant earthquake
• 6. D Tectonic earthquake beneath Mount Rainier

42
Volcanic Monitoring Associated Earthquake
Activity
Each type of ground-shaking event usually
generates a unique seismic "signature" that can
be recognized and identified as having been
"written" by a specific event. (Match activity
with signature.)
43
Volcanic Monitoring Magma Movement
Earthquake activity beneath a volcano almost
always increases before an eruption because magma
and volcanic gas must first force their way up
through shallow underground fractures and
passageways. When magma and volcanic gases or
fluids move, they will either cause rocks to
break or cracks to vibrate. When rocks break,
high-frequency earthquakes are triggered.
However, when cracks vibrate either low-frequency
earthquakes or a continuous shaking called
volcanic tremor is triggered.
44
Volcanic Monitoring Satellite Data

• Satellites can record infrared radiation where
  more heat or less heat shows up as different
  colors on a screen. When a volcano becomes
  hotter, an eruption may be coming soon.

45
Volcanic Monitoring Hazard Maps
46
Earthquake Monitoring Identification of
Faultlines
New Madrid, Tennessee
San Andreas Faultline
47
Earthquake Monitoring Remote Seismograph
Positioning

• Scientists consider seismic activity as it is
  registered on a seismometer.
• A volcano will usually register some small
  earthquakes as the magma pushes its way up
  through cracks and vents in rocks as it makes its
  way to the surface of the volcano.
• As a volcano gets closer to erupting, the
  pressure builds up in the earth under the volcano
  and the earthquake activity becomes more and more
  frequent.

48
Earthquake MonitoringAnalog vs. Digital

• This is an image of an analog recording of an
  earthquake. The relatively flat lines are periods
  of quiescence and the large and squiggly line is
  an earthquake.

• Below is a digital seismogram. The data is stored
  electronically, easy to access and manipulate,
  and much more accurate and detailed than the
  analog recordings.

49
Earthquake Monitoring Tiltmeter

• Tiltmeters attached to the sides of a volcano
  detect small changes in the slope of a volcano.
• When a volcano is about to erupt, the earth may
  bulge or swell up a bit.

Installing a tiltmeter
50
Earthquake Monitoring Changes in Groundwater
Levels

• Hydrogeologic responses to large distant
  earthquakes have important scientific
  implications with regard to our earths intricate
  plumbing system.
• The exact mechanism linking hydrogeologic changes
  and earthquakes is not fully understood, but
  monitoring these changes improves our insights
  into the responsible mechanisms, and may improve
  our frustratingly imprecise ability to forecast
  the timing, magnitude, and impact of earthquakes.

51
Earthquake Monitoring Observations of Strange
Behaviors in Animals

• The cause of unusual animal behavior seconds
  before humans feel an earthquake can be easily
  explain-ed.  Very few humans notice the smaller P
  wave that travels the fastest from the earthquake
  source and arrives before the larger S wave. But
  many animals with more keen senses are able to
  feel the P wave seconds before the S wave
  arrives.
• If in fact there are precursors to a significant
  earthquake that we have yet to learn about (such
  as ground tilting, groundwater changes,
  electrical or magnetic field variations), indeed
  its possible that some animals could sense these
  signals and connect the perception with an
  impending earthquake.

52
Match each feature on the diagram with its letter
designation (A-F).

• ___ Converging margin
• ___ Hot spot volcano
• ___ Transform fault
• ___ Rift volcano
• ___ Subduction volcano
• ___ Diverging margin

53
Match each feature on the diagram with its letter
designation (A-F).

• E Converging margin
• D Hot spot volcano
• C Transform fault
• A Rift volcano
• F Subduction volcano
• B Diverging margin

54
Volcanism at Plate Boundaries
Encyclopædia Britannica, Inc.
55
Volcanism Over Hot Spots (Oceanic and Continental)
56
Volcanism Hydrothermal Vents

• A hydrothermal vent is a geyser on the seafloor.
• In some areas along the Mid-Ocean Ridge, the
  gigantic plates that form the Earth's crust are
  moving apart, creating cracks and crevices in the
  ocean floor.
• Seawater seeps into these openings and is heated
  by the molten rock, or magma, that lies beneath
  the Earth's crust.
• As the water is heated, it rises and seeks a path
  back out into the ocean through an opening in the
  seafloor.

57
Plate Boundaries Ocean-Ocean Convergence

• When two oceanic plates converge one is usually
  subducted beneath the other and in the process a
  deep oceanic trench is formed.
• Oceanic-oceanic plate convergence also results in
  the formation of undersea volcanoes.

58
Plate Boundaries Ocean-Continent Convergence

• When an oceanic plate pushes into and subducts
  under a continental plate, the overriding
  continental plate is lifted up and a mountain
  range is created.
• This type of convergent boundary is similar to
  the Andes or the Cascade Range in North America.

59
Plate Boundaries Continent to Continent
Convergence

• When two continents meet head-on, neither is
  subducted because the continental rocks are
  relatively light and, like two colliding
  icebergs, resist downward motion. Instead, the
  crust tends to buckle and be pushed upward or
  sideways.

60
Plate Boundaries Divergent Plate Boundaries -
Oceanic
When a divergent boundary occurs beneath oceanic
lithosphere, the rising convection current below
lifts the lithosphere producing a mid-ocean ridge.
61
Plate Boundaries Divergent Plate Boundaries -
Continental
When a divergent boundary occurs beneath a thick
continental plate, the pull-apart is not vigorous
enough to create a clean, single break through
the thick plate material. Here the thick
continental plate is arched upwards from the
convection current's lift, pulled thin by
extensional forces, and fractured into a
rift-shaped structure.
62
Plate Boundaries Transform Plate Boundaries at
Mid-Ocean Ridges

• Transform-Fault Boundaries are where two plates
  are sliding horizontally past one another. These
  are also known as transform boundaries or more
  commonly as faults.
• Most transform faults are found on the ocean
  floor. They commonly offset active spreading
  ridges, producing zig-zag plate margins, and are
  generally defined by shallow earthquakes.

63
Plate Boundaries Rifting of Continental Plates
64
Plate Tectonics Seafloor Spreading

• Sea-floor spreading In the early 1960s,
  Princeton geologist Harry Hess proposed the
  hypothesis of sea-floor spreading, in which
  basaltic magma from the mantle rises to create
  new ocean floor at mid-ocean ridges.
• On each side of the ridge, sea floor moves from
  the ridge towards the deep-sea trenches where it
  is subducted and recycled back into the mantle

65
Geographical features associated with Plate
Tectonics

• Trenches - Deep, arcuate features, typically at
  the borders of the oceans where oceanic crust
  meets continental crust.
• Trenches also occur where one oceanic plate is
  diving below another oceanic plate.

• Mid-ocean ridges - Long mountain chains on the
  sea-floor that are elevated relative to the
  surrounding ocean floor.

66
Geographical features associated with Plate
Tectonics

• Mid-Plate (intraplate) volcanoes - The numerous
  volcanoes found far away from the spreading
  center, or mid-ocean ridge.
• Volcanoes formed either due to hot spots, or
  actually formed at the spreading center but were
  carried away along with the plate.
• Over time, the volcanoes stop accreting new
  material and sink below sea level as the oceanic
  crust cools. Sea mounts are volcanoes below sea
  level, and guyots are volcanoes below sea level
  in which the top has been planed off.
• Very old submerged volcanoes can become abyssal
  hills.

67
Geographical features associated with Plate
Tectonics

• Island or volcanic arcs - Found adjacent to
  trenches. Site where the rising magma from the
  subducting plate reaches the surface.
• These chains are arcuate owing to the spherical
  geometry of the Earth. Typically, these volcanoes
  have a mixed lithology between continental and
  oceanic crust (andesite).

68
Evidence of Sea Floor Spreading Magnetic
Reversals

• Magnetism on the ocean floor is orderly, arranged
  in long strips.
• The strips on the Atlantic ocean floor, in
  particular, are parallel to the mid-Atlantic
  ridge.
• Their structure and distribution are remarkably
  symmetric on both sides.

69
Evidence of Sea Floor Spreading Age of Sea Floor
as Opposed to Continents

• Scientists use the magnetic polarity of the sea
  floor to determine its age.
• Very little of the sea floor is older than 150
  million years. This is because the oldest sea
  floor is subducted under other plates and
  replaces by new surfaces.
• The tectonic plates are constantly in motion and
  new surfaces are always being created.
• This continual motion is evidenced by the
  occurrence of earthquakes and volcanoes.

70
Evidence of Sea Floor Spreading Fossil Evidence
71
Density Differences between Continental and
Oceanic Plates

• Continental margin - Because of the density
  difference between continental and oceanic crust,
  a particular geometry develops where the two
  types of crust meet.
• Starting from the continent, there is first a
  broad, flat zone called the "continental shelf."
• Then, near the end of continental crust, the
  angle increases and the area is called the
  "continental slope."
• Further out, at the actual border between the two
  crusts, the slope decreases, thus the
  "continental rise."

72
Faults Dip-Slip - Normal

• Normal faults happen in areas where the rocks are
  pulling apart (tensile forces) so that the rocky
  crust of an area is able to take up more space.
• The rock on one side of the fault is moved down
  relative to the rock on the other side of the
  fault.
• Normal faults will not make an overhanging rock
  ledge.
• In a normal fault it is likely that you could
  walk on an exposed area of the fault.

73
Faults Dip-Slip - Reverse

• Reverse faults happen in areas where the rocks
  are pushed together (compression forces) so that
  the rocky crust of an area must take up less
  space.
• The rock on one side of the fault is pushed up
  relative to rock on the other side.
• In a reverse fault the exposed area of the fault
  is often an overhang. Thus you could not walk on
  it.
• Thrust faults are a special type of reverse
  fault. They happen when the fault angle is very
  low.

74
Transform (strike-slip) Faults

• The movement along a strike slip fault is
  horizontal with the block of rock on one side of
  the fault moving in one direction and the block
  of rock along the other side of the fault moving
  in the other direction.
• Strike slip faults do not make cliffs or fault
  scarps because the blocks of rock are not moving
  up or down relative to each other.

75
Faults Normal and Reverse

• Normal Normal faults form when the hanging wall
  drops down. The forces that create normal faults
  are pulling the sides apart (extensional).
• Reverse Reverse faults form when the hanging
  wall moves up. Forces creating reverse faults are
  compressional, pushing the sides together.

76
HANGING WALL VS FOOTWALL

• Vertical faults are the result of up or down
  movement along a break in the rocks.
• Actually, both blocks may move up or both blocks
  may drop, or one might go up and one might go
  down.
• It is the end result of the movement that
  classifies the relationship between the blocks.

77
HANGING WALL VS FOOTWALL

• The hanging wall block is the one on the left and
  the foot wall block is the one on the right.

78
Faults Strike-Slip

• Strike-slip faults have walls that move sideways,
  not up or down.
• The forces creating these faults are lateral or
  horizontal, carrying the sides past each other.

79
Faults Transform

• Transform boundaries occur when the two plates
  move past one another. This is primarily a
  function of equal density of the plates however,
  it also occurs due to the direction of movement.
• The boundary of movement is called the transform
  fault. In reality, it is rarely a singular fault
  but rather a zone.
• Outlying the transform faults are records of past
  tectonic activity called "fracture zones."

80
Climatic Effects of Volcanic Ejecta

• Volcanic dust blasted into the atmosphere causes
  temporary cooling.
• Volcanoes that release huge amounts of sulfur
  compounds affect the climate more strongly than
  those that eject just dust. Combined with
  atmospheric water, they form a haze of sulfuric
  acid that reflects a great deal of sunlight which
  may cause global cooling for up to two years.
  Much more at
• http//www.cotf.edu/ete/modules/volcanoes/vclimat
  e.html

81
Tsunamis
82
Tsunamis Origin

• Tsunamis can be generated by
• Large Earthquakes (megathrust events such as
  Sumatra, Dec. 26, 2004)
• Underwater or near-surface volcanic eruptions
  (Krakatoa, 1883)
• Comet or asteroid impacts (evidence for tsunami
  deposits from the Chicxulub impact 65 mya)
• Large landslides that extend into water (Lituya
  Bay, AK, 1958)
• Large undersea landslides (evidence for
  prehistoric undersea landslides in Hawaii and off
  the east coast of North America)

83
Tsunamis Origin
84
Tsunamis Wave Characteristics
Tsunami wave propagation characteristics note
that as water depth becomes smaller, waves slow
down, become shorter wavelength, and have larger
amplitude.
85
Tsunamis Warning System

• A tsunami warning system is a system to detect
  tsunamis and issue warnings to prevent loss of
  life and property.
• It consists of two equally important components
  (1) a network of sensors to detect tsunamis and
  (2) a communications infrastructure to issue
  timely alarms to permit evacuation of coastal
  areas.

Tsunami Monitoring Buoy Reports rises in the
water column and tsunami events
86
Stages in the life of a Tsunamis Initiation

• Near the source of sub-marine earthquakes, the
  seafloor is "permanently" uplifted and
  down-dropped, pushing the entire water column up
  and down.
• The potential energy that results from pushing
  water above mean sea level is then transferred to
  horizontal propagation of the tsunami wave
  (kinetic energy).

87
Stages in the life of a Tsunamis Split

• Within several minutes of the earthquake, the
  initial tsunami is split into a tsunami that
  travels out to the deep ocean (distant tsunami)
  and another tsunami that travels towards the
  nearby coast (local tsunami).

88
Stages in the life of a Tsunamis Amplification

• Several things happen as the local tsunami
  travels over the continental slope. Most obvious
  is that the amplitude increases. In addition, the
  wavelength decreases. This results in steepening
  of the leading wave--an important control of wave
  runup at the coast.

89
Stages in the life of a Tsunamis Runup

• Tsunami runup occurs when a peak in the tsunami
  wave travels from the near-shore region onto
  shore.
• Runup is a measure-ment of the height of the
  water onshore observed above a reference sea
  level.

90
Seismic Waves Primary (P)

• P-waves are the fastest type of seismic wave. As
  P-waves travel, the surrounding rock is
  repeatedly compressed and then stretched.
• (Note S and P waves are classified as body
  waves.)

91
Seismic Waves Secondary (S)

• S-waves arrive after P-waves because they travel
  more slowly. The rock is shifted up and down or
  side to side as the wave travels through it.

92
Seismic Waves Surface Waves

• Rayleigh waves, also called ground roll, travel
  like ocean waves over the surface of the Earth,
  moving the ground surface up and down. They cause
  most of the shaking at the ground surface during
  an earthquake.
• Love waves are fast and move the ground from side
  to side.

93
Seismic Waves Primary (P)

• The fastest wave, and therefore the first to
  arrive at a given location.
• Also known as compressional waves, the P wave
  alternately compresses and expands material in
  the same direction it is traveling.
• Can travel through all layers of the Earth.

USGS
94
Seismic Waves Secondary Waves (S)

• The S wave is slower than the P wave and arrives
  next, shaking the ground up and down and back and
  forth perpendicular to the direction it is
  traveling.
• Also know as shear waves.

USGS
95
Seismic Waves Surface Waves

• Surface waves follow the P and S waves.
• Also known as Rayleigh and Love waves.
• These waves travel along the surface of the earth.

USGS
96
Seismic Waves MeasurementIntensity vs. Magnitude

• Magnitude scales, like the Richter magnitude and
  moment magnitude, measure the size of the
  earthquake at its source.
• Magnitude does not depend on where the
  measurement of the earthquake is made.
• On the Richter scale, an increase of one unit of
  magnitude (for example, from 4.6 to 5.6)
  represents a 10-fold increase in wave amplitude
  on a seismogram or approximately a 30-fold
  increase in the energy released.

• Intensity scales measure the amount of shaking at
  a particular location.
• The intensity of an earthquake will vary
  depending on where you are.

97
Seismic Waves Measurement Intensity

• I. Not felt except by a very few under especially
  favorable conditions.
• II. Felt only by a few persons at rest,
  especially on upper floors of buildings.
• III. Felt quite noticeably by persons indoors,
  especially on upper floors of buildings. Many
  people do not recognize it as an earthquake.
  Standing motor cars may rock slightly. Vibrations
  similar to the passing of a truck. Duration
  estimated.
• IV. Felt indoors by many, outdoors by few during
  the day. At night, some awakened. Dishes,
  windows, doors disturbed walls make cracking
  sound. Sensation like heavy truck striking
  building. Standing motor cars rocked noticeably.
• V. Felt by nearly everyone many awakened. Some
  dishes, windows broken. Unstable objects
  overturned. Pendulum clocks may stop.
• VI. Felt by all, many frightened. Some heavy
  furniture moved a few instances of fallen
  plaster. Damage slight.
• VII. Damage negligible in buildings of good
  design and construction slight to moderate in
  well-built ordinary structures considerable
  damage in poorly built or badly designed
  structures some chimneys broken.
• VIII. Damage slight in specially designed
  structures considerable damage in ordinary
  substantial buildings with partial collapse.
  Damage great in poorly built structures. Fall of
  chimneys, factory stacks, columns, monuments,
  walls. Heavy furniture overturned.
• IX. Damage considerable in specially designed
  structures well-designed frame structures thrown
  out of plumb. Damage great in substantial
  buildings, with partial collapse. Buildings
  shifted off foundations.
• X. Some well-built wooden structures destroyed
  most masonry and frame structures destroyed with
  foundations. Rails bent.
• XI. Few, if any (masonry) structures remain
  standing. Bridges destroyed. Rails bent greatly.
• XII. Damage total. Lines of sight and level are
  distorted. Objects thrown into the air.

98
Seismic Waves Measurement Focal Depth

• The vibrations produced by earthquakes are
  detected, recorded, and measured by instruments
  call seismographs.
• The zig-zag line made by a seismograph, called a
  "seismogram," reflects the changing intensity of
  the vibrations by responding to the motion of the
  ground surface beneath the instrument.
• From the data expressed in seismograms,
  scientists can determine the time, the epicenter,
  the focal depth, and the type of faulting of an
  earthquake and can estimate how much energy was
  released.

99
EARTHQUAKE VOLCANOES QUIZ

• Check your knowledge of Earthquakes and
  Volcanoes. Number from 1 to 10 on a sheet of
  scratch paper. You will be asked a series of ten
  questions. The answer to each question will
  appear on the slide immediately following each
  question.

100
EARTHQUAKE VOLCANOES QUIZ

• 1. The time lag between which two seismic waves
  may be used to determine the distance from the
  focus of an earthquake?

101
EARTHQUAKE VOLCANOES QUIZ

• 1. The time lag between which two seismic waves
  may be used to determine the distance from the
  focus of an earthquake? P and S

102
EARTHQUAKE VOLCANOES QUIZ

• 2. Is new oceanic crust added at divergent or
  convergent plate boundaries?

103
EARTHQUAKE VOLCANOES QUIZ

• 2. Is new oceanic crust added at divergent or
  convergent plate boundaries? DIVERGENT

104
EARTHQUAKE VOLCANOES QUIZ

• 3. Does an ocean basin decrease or increase in
  size when its rate of subduction exceeds its rate
  of crust production?

105
EARTHQUAKE VOLCANOES QUIZ

• 3. Does an ocean basin decrease or increase in
  size when its rate of subduction exceeds its rate
  of crust production? DECREASE

106
EARTHQUAKE VOLCANOES QUIZ

• 4. What nearly landlocked sea was formed during
  rifting of the African and Eurasian plates?

107
EARTHQUAKE VOLCANOES QUIZ

• 4. What nearly landlocked sea was formed during
  rifting of the African and Eurasian plates?
  MEDITERRANEAN

108
EARTHQUAKE VOLCANOES QUIZ

• 5. Identify the worlds deepest ocean trench,
  located where the Pacific Plate is slipping
  beneath the Philippine plate.

109
EARTHQUAKE VOLCANOES QUIZ

• 5. Identify the worlds deepest ocean trench,
  located where the Pacific Plate is slipping
  beneath the Philippine plate. MARIANAS

110
EARTHQUAKE VOLCANOES QUIZ

• 6. From the name of which mythological Roman
  blacksmith was the term volcano derived?

111
EARTHQUAKE VOLCANOES QUIZ

• 6. From the name of which mythological Roman
  blacksmith was the term volcano derived? VULCAN

112
EARTHQUAKE VOLCANOES QUIZ

• 7. What unifying theory attempts to explain the
  major events in the evolution of Earths surface?

113
EARTHQUAKE VOLCANOES QUIZ

• 7. What unifying theory attempts to explain the
  major events in the evolution of Earths surface?
  PLATE TECTONICS

114
EARTHQUAKE VOLCANOES QUIZ

• 8. Are stratovolcanoes associated with subduction
  zones or hot spots?

115
EARTHQUAKE VOLCANOES QUIZ

• 8. Are stratovolcanoes associated with subduction
  zones or hot spots? SUBDUCTION ZONES

116
EARTHQUAKE VOLCANOES QUIZ

• 9. What tectonic feature lies directly above the
  focus of an earthquake?

117
EARTHQUAKE VOLCANOES QUIZ

• 9. What tectonic feature lies directly above the
  focus of an earthquake? EPICENTER

118
EARTHQUAKE VOLCANOES QUIZ

• 10. What surface depression is created by the
  collapse of an empty magma chamber?

119
EARTHQUAKE VOLCANOES QUIZ

• 10. What surface depression is created by the
  collapse of an empty magma chamber? CALDERA

120
EARTHQUAKE VOLCANOES QUIZ

• Source of questions
• New 2010 version of The Game of EARTH
• www.otherworlds-edu.com

121
5. Scoring

• Points will be awarded for the quality and
  accuracy of responses. Ties will be broken by the
  accuracy and/or quality of answers to
  pre-selected questions.

122
5. Scoring

• Points will be awarded for the quality and
  accuracy of responses. Ties will be broken by the
  accuracy and/or quality of answers to
  pre-selected questions.

123
7. NATIONAL SCIENCE EDUCATION STANDARDS

• Content Standard D. Structure of the Earth
  System Earths history.

124
Additional Resources

• Volcanic Hazards Prediction of Volcanic
  Eruptions http//www.tulane.edu/sanelson/geol204
  /volhazpred.htm
• NSTA PowerPoint Presentation on Tsunamis
• http//web.ics.purdue.edu/braile/edumod/tsunami/
  Tsunami!.ppt
• Hydrothermal vents
• http//www.ceoe.udel.edu/deepsea/level-2/geology/v
  ents.html
• Plate boundaries
• http//www.platetectonics.com/book/page_5.asp

125
Additional Resources

• PowerPoint of Seafloor Spreading
• http//www.sci.csuhayward.edu/lstrayer/geol2101/2
  101_Ch19_03.pdf
• Windows to the Universe Earthquakes
• http//www.windows.ucar.edu/tour/link/earth/geolo
  gy/quake_1.html