First quarter lesson in Science 10

1. SCIENCE 10
RominaC. Quilla
SubjectTeacher
FIRST QUARTER- Earth and Space

2. Plate Tectonics
Earthquake epicenters and Its Relation
to Plate Tectonics
MELC Quarter 1 Week 1-3
Describe and relate the distribution of active volcanoes,
earthquake epicenters, and major mountain belts to Plate
Tectonic Theory

3. Question 1
 What is the name of the Mesozoic
supercontinent that consisted of all the present
continents?
PANGAEA

4. Question 2
 Which earthquake waves travel
through the outer core?
PRIMARY WAVES or P-WAVES

5. Question 3
 These are systematic waves that are created
due to the sudden release of energy in the
Earth crusts.
EARTHQUAKE

6. Question 4
 A method used by seismologists in
locating the epicenter of an earthquake.
TRIANGULATION METHOD

7. Question 5
 What theory states that the Earth’s outer
layer is broken into large slowly moving
pieces?
PLATE TECTONICS THEORY

8. Structure of the Earth
 The Earth is made up of 3
main layers:
 Crust
 Mantle
 Core
Inner core
Outer core
Mantle
Crust
•The interior of the Earth is
divided into layers based on
chemical and physical
properties.

9. Structure of the Earth
Inner core
Outer core
Mantle
Crust
•The Earth has an
outer silica-rich, solid
crust, a highly
viscous mantle, and
a core comprising a
liquid outer core that
is much less viscous
than the mantle, and
a solid inner core.

10. Lithosphere
 Rigid layer that can break
under stress
 Comprises the crust and
the upper most layer of
the mantle
 Crust is composed of
major and minor blocks of
rocks which we refer to as
tectonic plates

11. Lithosphere
 Continental crust is thicker but less dense than the oceanic
crust.
 Continental crust floats higher than the oceanic crust because of
density difference

12. The lithosphere (solid part of the
Earth) is composed of three major
layers, the crust (outermost layer),
the mantle (the middle layer), and
the core (the innermost layer).
The Earth’s crust is composed of several
broken plates that move continuously.
These movements are caused by the
properties and processes that occur in the
Earth’s interior.
Due to intense heat in the Earth’s
interior, the molten rock (magma) in
the mantle moves in a cyclic pattern
forming convection cells (Figure
1.1).
In the cell, the warmer material from
the lower layer of the mantle near the
core rises.
As it rises, moving away from
the core, it slowly cools down
and eventually sinks again
and is replaced by the rising
warmer material forming a
never-ending cycle.
This movement is extremely
slow that its effects can only
be discerned after thousands
or millions of years.
Figure 1.1. The Convection Cell

13. Theories on the movement of
the lithosphere:
 Continental Drift theory (Alfred Wegener)
(Oskin, 2017)
 This theory states that the Earth was once composed of
only one supercontinent called Pangaea.
 Through time, this supercontinent split into two sub-
continents, Laurasia and Gondwanaland.
 Million years further, Laurasia split into a few smaller
continents forming the continents in the northern
hemisphere of the Earth. This includes Asia, Europe,
North America, South America, and Africa.
 On the other hand, the continents of the southern
hemisphere, Australia and Antarctica, are the two
continents divided from Gondwanaland.

14. An German
climatologist, who
first noted the
theory on the
movement of the
Earth’s land masses
and is known today
as the modern
Plate Tectonic
Theory (Oskin,
2017). This theory
states that the
Earth’s crust is
composed of
several broken
plates that
continuously move
either away, past,
or towards each
other.
In the early
1900s, he observed
that the coastal
areas of the
continents today
seemed to look like
jigsaw puzzle
pieces that fit to
each other. With
this observation,
he inferred that
the Earth could
have once been
composed of only
one continent and
was split into
several smaller
continents due to
lithospheric
processes through
time.
Google.image
Alfred Wegener

15. Theories on the movement of
the lithosphere:
 Seafloor Spreading Theory
(www.divediscover.whoi.edu)
 Proposed by Harry Hess of Princeton
University
 States that the seafloor is continuously
spreading, and the extra crust gets
recycled into the mantle

16. Theories on the movement of
the lithosphere:
 Plate Tectonics Theory (www.ck12.org;
Oskin, 2017)
 States that the crust is composed of
different plates which move either
towards, away or past each other.
 The modern version of the Continental
Drift Theory of Alfred Wegener

17. What is Plate Tectonics?

18.  If you look at a map of the world, what do you notice?
you may notice that some of the continents
could fit together like pieces of a puzzle.

20. Plate Tectonics
 The Earth’s crust is divided into 15 major
plates which are moved in various directions.
 This plate motion causes them to collide, pull
apart, or scrape against each other.
 Each type of interaction causes a
characteristic set of Earth structures or
“tectonic” features.
 The word, tectonic, refers to the deformation
of the crust as a consequence of plate
interaction.

21. • There are 15 major plates on
Earth, each of which slide around
at a rate of centimeters per year,
pulling away from, scraping
against or crashing into each
other.
• Each type of interaction produces
a characteristic “tectonic feature”,
like mountain ranges, volcanoes
and (or) rift valleys, that we will
discuss during this lecture.

22. World Plates
The Tectonic Plate of the World (Source: http://pubs.usgs.gov)

23. 15 Major Tectonic Plates
7 Primary Plates
• Eurasian Plate,
• Indo-Australian
Plate,
• Pacific Plate,
• North American
Plate,
• South American
Plate,
• African Plate, and
• Antarctic Plate
8 Secondary Plates
 Juan de Fuca Plate,
 Nazca Plate,
 Cocos Plate,
 Caribbean Plate,
 Philippine Plate,
 Arabian Plate,
 Indian Plate, and
 Scotia Plate

25.  We already learned that the mantle is
composed of semifluid molten rock that moves
constantly in a cyclic pattern forming
convection cells.
 As the molten rock moves in the mantle, with
the extreme pressure, some of the molten rock
escapes through the cracks in the crust and
along the boundaries of the tectonic plates
resulting in earthquakes and volcanic activities
(National Geographic, 2014).

26.  Perhaps, the most known tectonic boundaries
that consist of many active volcanoes and
where frequent earthquakes occur is the Pacific
Ring of Fire.
 The “ring” is composed of the boundaries of the
Pacific Plate, Philippine Plate, Eurasian Plate,
Juan de Fuca and Cocos plates, and the Nazca
Plate.

27. The Tectonic Plate of the World (Source: http://pubs.usgs.gov)

28. Describe what is shown in the figure below. Identify the
plates that move away, past, or towards each other

29. Activity 1. Tectonic Puzzle

31. Earthquake
 shaking and trembling of the Earth’s
crust caused by a sudden release of
energy.
 occurs when rocks along a certain
fault line suddenly move.

32. Have you ever wondered what makes the
Philippines susceptible to earthquakes?
https://www.nationalgeographic.org/article/plate-tectonics-ring-fire/
The “ring” is composed of the boundaries of the Pacific Plate, Philippine Plate,
Eurasian Plate, Juan de Fuca and Cocos plates, and the Nazca Plate.

33. The study of earthquakes and the
waves they create is called seismology
(from the Greek word “seismos” which
means “to shake”). In turn, scientists
who study earthquakes are called
seismologists. During an earthquake, a
sudden release of stored energy in the
Earth’s crust creates seismic waves.
Sometimes they cause tsunamis and
fire which may lead to loss of life and
huge damage to property.

34. How would the surroundings be
affected during an earthquake?
 As an earthquake occurs, energy
moves out in all directions from the
focus.
 The energy that is released is
carried by a vibration called seismic
waves.

35. Seismic Wave
 Seismic waves are the waves of energy
caused by the sudden breaking of rock within
the earth or an explosion. They are the
energy that travels through the earth and is
recorded on seismographs.
 There are several different kinds of seismic
waves, and they all move in different ways.
The two main types of waves are body waves
and surface waves.

36. Body Waves
 P Waves (compression wave)
 The first kind of body wave is the P wave or primary wave.
 This is the fastest kind of seismic wave. The P wave can
move through solid rock and fluids, like water or the liquid
layers of the earth and gases. It pushes and pulls the rock it
moves through just like sound waves push and pull the air.
 It is considered as the first signal from an earthquake to be
felt.

37. Compressional Wave (P-Wave) Animation
Deformation propagates. Particle motion consists of alternating
compression and dilation. Particle motion is parallel to the
direction of propagation (longitudinal). Material returns to its
original shape after wave passes.

38. Body Waves
 S wave or shear wave (transverse wave)
 The second type of body wave is the S wave or secondary
wave, which is the second wave you feel in an earthquake.
An S wave is slower than a P wave and can only move
through solid rock. This wave moves rock up and down, or
side-to-side.
 The distance between the beginning of the first P wave and
the first S wave tells you how many seconds the waves are
apart. This number will be used to tell you how far your
seismograph is from the epicenter of the earthquake.

39. Shear Wave (S-Wave) Animation
Deformation propagates. Particle motion consists of alternating transverse
motion. Particle motion is perpendicular to the direction of propagation
(transverse). Transverse particle motion shown here is vertical but can be in
any direction. However, Earth’s layers tend to cause mostly vertical (SV; in the
vertical plane) or horizontal (SH) shear motions. Material returns to its original
shape after wave passes.

40. Surface Waves
 Love Waves
 The first kind of surface wave is called a Love wave,
named after Augustus Edward Hough Love, a British
mathematician who worked out the mathematical
model for this kind of wave in 1911. It's the fastest
surface wave and moves the ground from side-to-side.

41. Love Wave (L-Wave) Animation
Deformation propagates. Particle motion consists of alternating transverse
motions. Particle motion is horizontal and perpendicular to the direction of
propagation (transverse). To aid in seeing that the particle motion is purely
horizontal, focus on the Y axis (red line) as the wave propagates through it.
Amplitude decreases with depth. Material returns to its original shape after
wave passes.

42. Surface Waves
 Rayleigh Waves
 The other kind of surface wave is the Rayleigh wave, named
for John William Strutt (Lord Rayleigh), who mathematically
predicted the existence of this kind of wave in 1885. A
Rayleigh wave rolls along the ground just like a wave rolls
across a lake or an ocean. Because it rolls, it moves the
ground up and down, and side-to-side in the same direction
that the wave is moving. Most of the shaking felt from an
earthquake is due to the Rayleigh wave, which can be much
larger than the other waves.

43. Rayleigh Wave (R-Wave) Animation
Deformation propagates. Particle motion consists of elliptical motions
(generally retrograde elliptical) in the vertical plane and parallel to the
direction of propagation. Amplitude decreases with depth. Material returns
to its original shape after wave passes.

44. Deformation propagates. Particle motion consists of
alternating compression and dilation. Particle motion is
parallel to the direction of propagation (longitudinal).
Material returns to its original shape after wave passes.
Four Types of Seismic Waves (http://web.ics.purdue.edu/~braile
/new/SeismicWaves4Types.ppt)
Deformation propagates. Particle motion consists of
alternating transverse motion, perpendicular to direction of
propagation. Transverse motion can be in any direction.
Material returns to its original shape after wave passes.
Deformation propagates. Particle motion consists of
elliptical motions (generally retrograde elliptical) in the
vertical plane and parallel to the direction of propagation.
Amplitude decreases with depth. Material returns to its
original shape after wave passes.
Deformation propagates. Particle motion consists of
alternating transverse motions. Particle motion is
horizontal and perpendicular to the direction of
propagation (transverse). Amplitude decreases with depth.
Material returns to its original shape after wave passes.

45. You can download the animations separately to run more efficiently:
http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm
A complete PowerPoint presentation on the Seismic wave animations is also available at:
http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.ppt
Demonstrate the AmaSeis software for displaying and analyzing seismograms;
software available at: http://bingweb.binghamton.edu/~ajones/
A tutorial on AmaSeis and links to seismograms that can be downloaded and
viewed in AmaSeis available at:
http://web.ics.purdue.edu/~braile/edumod/as1lessons/UsingAmaSeis/UsingAmaSeis.htm
IRIS Seismographs in Schools program: http://www.iris.edu/hq/sis
IRIS Wave Visualizations:
http://www.iris.edu/hq/programs/education_and_outreach/visualizations
USGS/SCEC SAF EQ Simulations:
http://earthquake.usgs.gov/regional/nca/simulations/shakeout/
Quake Catcher Network – MEMS accelerometers: http://quakecatcher.net/
Graphical earthquake location method illustrating locations using p-wave arrival
times (similar to the optimization method used by seismologists):
http://web.ics.purdue.edu/~braile/edumod/eqlocate/tutorial.htm
S-P earthquake location tutorial:
http://web.ics.purdue.edu/~braile/edumod/as1lessons/EQlocation/EQlocation.h

47. Earthquake
Seismic Waves
Body waves Surface waves
Primary waves Secondary
waves
Love waves Rayleigh waves

48. Surface Waves that Occur Underwater
 Earthquakes that occur
underwater can produce
huge surface waves on the
ocean called Tsunamis
 Tsunamis come in all sizes
from 2 m to 30 meters tall
 Tsunamis can travel
thousands of kilometers
 In the deep oceans waves
that cause tsunamis may
begin at 1 meter high, but
as they near land the
tsunamis slow down in
shallow waters to allow the
waves in the back to catch
up with the waves in the
front and pile on

49. Detecting Seismic waves
 To detect and measure earthquake waves scientists use
seismographs
 A seismograph records the ground movements caused by
seismic waves as they move through the earth
The frame of the seismograph is attached
to the ground, so the frame shakes when
seismic waves arrive
Seismographs use to have pens attached to
the frame that would wiggle back and
forth on a roll of paper as the ground
shook, but now electronic seismographs
are used

50. Detecting Seismic waves
P waves arrive at the seismograph first
followed by slower moving S waves
Scientists can tell how far away the
earthquake was by measuring the
time of arrival between P and S
waves
Scientists can tell where an
earthquake occurred by using three
seismographs at three different
locations

51. Seismology
The study of earthquakes
and the waves they created
is called seismology (from
the Greek word “seismos”
which means “to shake”).

52. Seismographs
 Seismographs can be used to find
valuable resources such as water and oil
 Geologists will set off explosives at the
Earth’s surface
 Seismic waves from the explosions
reflect from structures underground
 Seismographs are then used to locate
the underground resources

53. epicenter is usually the location
where the waves from an
earthquake are highly intense.
location below the earth’s
surface where the
earthquake starts is
called the hypocenter or
focus

55. How locate the epicenter of an
earthquake?
 Triangulation Method

57. How did scientists gain information
about the Earth’s internal structure?
 By studying how seismic waves travel through the
Earth.
 It involves measuring the time it takes for both
types of waves to reach the seismic stations from
the epicenter of an earthquake.
 An epicenter is a point in the Earth’s surface
directly above the focus.
 Since P waves travel faster than S waves, they are
always detected first.
 The farther away from the epicenter means the
longer time interval between the arrival of P and S
waves.

58. How did scientists gain information
about the Earth’s internal structure?
 1909, Yugoslavian seismologist, Andrija
Mohorovicic found out that the velocity of
seismic waves changes and increases at a
distance of about 50 km below the Earth’s
surface.
 This led to the idea that there is a difference in
density between the crust and the mantle.

59. Mohorovicic Discontinuity
 Moho
 Boundary between the crust and the
mantle

60. Seismic waves as they travel through
the Earth
 P waves can travel through liquids while S waves
cannot.
 During an earthquake, the seismic waves radiate
from the focus.
 The waves bend due to change in density of the
medium.
 As the depth increases, the density also increases

61. Seismic waves as they travel through
the Earth
 P waves are detected on
the other side of the Earth
opposite the focus.
 A shadow zone from 103˚
to 142˚ exists from P
waves (see figure)
 Since P waves are detected
until 103˚, disappear from
103˚ to 142˚, then
reappear again, something
inside the Earth must be
bending the P waves.

62. A seismic shadow zone is an area of the Earth's
surface where seismographs cannot detect
direct P waves and/or S waves from
an earthquake. This is due to liquid layers or
structures within the Earth's surface. The most
recognized shadow zone is due to the core-
mantle boundary where P waves are refracted
and S waves are stopped at the liquid outer core;
however, any liquid boundary or body can create
a shadow zone.
For example, magma reservoirs with a high
enough percent melt can create seismic shadow
zones.

63. Gutenberg Discontinuity
 Beno Gutenberg, German seismologist
 Existence of the shadow zone, could only be
explained if the Earth contained a core
composed of a material different from that
of the mantle causing the bending of the P
waves.
 Boundary between mantle and core

64. Seismic waves as they travel
through the Earth
 From the epicenter, S waves are detected until 103˚,
from that point S waves are no longer detected.
 This observation tells us that the S waves do not travel
all throughout the Earth’s body.
 There is a portion inside the Earth that does not
conduct the propagation of S wave.
 Knowing the properties and characteristics of S waves
(that it cannot travel through liquids), and with the
idea that P waves are bent to some degree, this portion
must be made of liquid, thus the outer core.

65. Seismic waves as they travel through
the Earth
 1936, Danish seismologist, Inge Lehmann
 Predicted the innermost layer of the Earth
 Discovered a new region of seismic reflection within the
core.
 Earth has a core within a core
 The outer part of the core is liquid based on the
production of an S wave shadow and the inner part must
be solid with a different density than the rest of the
surrounding material.
 The size of the inner core was accurately calculated
through nuclear underground tests (echoes from seismic
waves) conducted in Nevada.

66. The magnitude of an earthquake is based on the measurement of
the maximum motion recorded by a seismograph. The most
commonly used are the Local Magnitude (ML) or known as the
Richter magnitude, the surface wave magnitude (Ms), body –
wave magnitude (Mb), and moment magnitude (Mw).
An earthquake aftermath in
Davao City,Philippines
(October 31, 2019)

67. How can we measure an earthquake?
 Earthquake can be measured using a
Richter Scale and Mercalli Scale.
 Intensity is a measure of the amount of
earth shaking that happens at a given
location.
 This can be measured through the Richter
Scale.
 Magnitude, on the other hand, measures
the size of the seismic waves or the
amount of energy released at the source
of the earthquake and will be measured
using a Mercalli Scale.

68. How strong is an Earthquake?
INTENSITY EFFECTS TO PEOPLE MAGNITUDE
1 not felt by many Instrumental
2 felt by few Feeble
3 felt by few indoors Slight
4 felt by many indoors Moderate
5 felt by almost everyone Rather Strong
6 felt by all Strong
7 find damages to few buildings Very strong
8 slight damage to specially
designed structures
Destructive
9 destroyssome well-built
woodenstructures
Ruinous
10 destroys well-built wooden
structures
Disastrous
11 destroys bridges and railways Very disastrous
12 Total Damage Catastrophic

69. What to do before an Earthquake
 Must prepare a fire extinguisher;
 First aid kit;
 Battery powered radio;
 Emergency light/flashlights with extra battery;
 Must learn to turn off gas, electricity and
water;
 Heavy objects must not be placed above the
head level; and
 Make a plan where to meet with your family.

70. What to do during an Earthquake
 Stay calm.
 If you are outdoors, stay in an open area
far away from power lines or anything
that might fall.
 if you are indoors, stay inside and observe
the Drop-Cover-Hold protocol.
 In case you are in a high rise building, do
not use the elevators.

71. What to do after an Earthquake
 Be prepared for aftershocks.
 Listen to the radio, or television, for information.
 Check your home for any damages.
 Wear protective clothing and sturdy shoes.

72. EARTHQUAKE DRILL
DROP COVER HOLD

73. QUESTIONS

74. Thank you and God Bless