4. a theory in geology: the
lithosphere of the earth is divided
into a small number
of plates which float on and travel
independently over the mantle
and much of the earth's seismic
activity occurs at the boundaries
of these plates
7. Entire lithosphere of the Earth is broken
into numerous segments called lithospheric
plates.
The slow but constant moving of these
plates is called tectonics, thus moving
lithospheric plates is called plate tectonics.
One of the consequences of these plate
movements is EARTHQUAKE.
8.
9.
10. Objective: Locate the epicenter
of an earthquake using
triangulation method
What data are needed?
1.At least three(3) recording stations
2. Time difference in the arrival of P-wave and S-
wave in each station
3. Distance of epicenter from each station using
the formula
14. Q1.Where is the epicenter of this hypothetical earthquake?Use
triangulation method.
- CEBU
Q2.What difficulty will you encounter if you only have data
from two recording stations?
Two recording stations would result to two epicenters.
Q3.What is the distance of the epicenter from the seismic station? -
9000 km.
Q4.What do you think is the importance of determining
the epicenter of an earthquake?
It will help in assessing the damage zone where death and
destruction will be maximum.Thus, helps in planning
post-earthquake rehabilitation and relief measures, in
forewarning of tsunami-related hazard and in assuring
of minimum loss to life and property if it is the deserted
or inhabited region
15. Let’s see how early geologists used the
plotted positions of earthquake epicenters
throughout the world in conceptualizing
crustal movements.
17. ACTIVE VOLCANOES DISTRIBUTION
Where are the volcanoes located?
Compare the location of majority of
earthquake
volcanoes
epicenters with the location of
18. MOUNTAIN RANGES DISTRIBUTION
How will you relate the distribution of
mountain ranges with the distribution of
earthquake epicenters and volcanoes?
19. What do you think is the
basis of scientists in
dividing Earth’s lithosphere
into several plates?
The places on Earth where most of the
earthquakes originated or some mountains
and volcanoes were formed mark the
boundaries of each lithospheric plate.
23. PLATE BOUNDARIES (RECALL)
Determining location of earthquake epicenters
plays a vital role in laying the foundation of
plate tectonics.
The places on Earth where most of the
earthquakes originated or some of the
mountains and volcanoes were formed
marked the boundaries of each lithospheric
plates
24.
25. 3 TYPESOF PLATE BOUNDARIES
DIVERGENT PLATE BOUNDARY
2 lithospheric plates move away from
each other
CONVERGENT PLATE BOUNDARY
2 lithospheric plates move toward
each other
TRANSFORM FAULT
2 lithospheric plates slide past each other
32. Questions:
1.What are common in four
pictures?
2.Million of years ago, landmasses
in each picture were once connected
.What do you think is happening to
the Earth’s crust in those pictures?
3. If this event continues for million
of years, what do you think will be
the effect on the crust?
34. Types of divergent plate boundary
1. continental divergence
-As the two plates pull apart, normal faults develop on
both sides of the rift, and the central blocks slide
downwards
Early in the rift-forming process, streams and rivers
will flow into the sinking rift valley to form a long
linear lake.
As the rift grows deeper it might drop below sea level,
allowing ocean waters to flow in.This will produce a
narrow, shallow sea within the rift.
This rift can then grow deeper and wider. If rifting
continues, a new ocean basin could be produced.
35.
36.
37. Example
The East Africa RiftValley is a classic example of
this type of plate boundary.The East Africa Rift is
in a very early stage of development.The plate
has not been completely rifted, and the rift valley
is still above sea level but occupied by lakes at
several locations.The Red Sea is an example of a
more completely developed rift.There the plates
have fully separated, and the central rift valley
has dropped below sea level.
38. GEOLOGICAL EFFECTS
a rift valley sometimes occupied by long
linear lakes or a shallow arm of the
ocean; numerous normal faults
bounding a central rift valley;
shallow earthquake activity along the
normal faults.
Volcanic activity sometimes occurs
within the rift.
39. 2. Oceanic Divergence
When a divergent boundary occurs beneath
oceanic lithosphere, the rising convection
current below lifts the lithosphere, producing a
mid-ocean ridge.
Extensional forces stretch the lithosphere and
produce a deep fissure.When the fissure opens,
pressure is reduced on the super-heated mantle
material below.
It responds by melting, and the new magma
flows into the fissure.The magma then solidifies
and the process repeats itself.
40.
41.
42. example
The Mid-Atlantic Ridge is a classic example of
this type of plate boundary.The Ridge is a
high area compared to the surrounding
seafloor because of the lift from the
convection current below.
43. GEOLOGICAL EFFECTS
a submarine mountain range such as the Mid-
Atlantic Ridge;
volcanic activity in the form of fissure
eruptions;
shallow earthquake activity;
creation of new seafloor and a widening
ocean basin.
44.
45. …..is divergent boundary also known as
constructive plate boundary?
46. ASSESSMENT
Which of the following is NOT an example
of a divergent plate boundary?
a.The boundary between the Nazca Plate and
theSouthAmerican Plate
b.The boundary between the NorthAmerican
Plate and the Eurasian Plate
c.The EastAfrican Rift
d.The plate boundary that passes over Iceland
47. Which of the following describes a divergent
boundary?
a.
b.
When two plates collide with each other
When two plates interact in any way
c.When two plates move apart from each other
d.When two plates slide alongside each other
48. What feature forms near divergent
boundaries between two pieces of oceanic
crust?
a. Mid-ocean ridge
b. Non-volcanic mountain
c. Continental rift valley
d.Trench
49. What feature forms near divergent
boundaries between two pieces of
continental crust?
a.continental rift valley
b. non-volcanic mountain
c. mid-ocean ridge
d. canyon
52. CONVERGENT PLATE BOUNDARY
occur where the Earth’s tectonic plates collide
or move toward one another.
As the plates converge, the denser, thinner
tectonic plate subducts or dives beneath the
lighter, thicker, more buoyant tectonic plate.
55. Remember
Continental plates are thicker
but less dense than
oceanic plates.
Continental crust is too light to be carried
downward into a trench. At continental-
continental convergent margins neither plate
subducts.The two plates converge,
buckle, fold, and fault.
56. Example
Himalayas when the Indian-Australian plate
collided with the Eurasian plate.
-Alps,( collision betweenAfrican and Eurasian
plate)
- Appalachians(Mountain range in the eastern
UnitedStates andCanada)
- Atlas (series of mountain ranges in
northwesternAfrica)
57. GEOLOGICAL EFFECTS
intense folding and faulting;
a broad folded mountain range;
shallow earthquake activity;
shortening and thickening of the plates
within the collision zone.
58. Mount Everest, the tallest mountain in the
world, grows about 2.5 inches each year?
60. Remember
Older oceanic plates are
denser than younger ones;
denser plates subduct.
An oceanic-oceanic collision is when two
tectonic oceanic plates collide.This
convergence creates a subduction zone, which is
where one plate is submerged below the other.
61. What happens after the
subduction?
As the ocean floor crust (oceanic plate) loaded with
sediments subducts into the softer asthenosphere,
the rocks in the subduction zone
become metamorphosed (alteration of the
composition or structure of a rock) under high
pressure and temperature.
After reaching a depth of about 100 km, the plates
melt. Magma (metamorphosed sediments and the
melted part of the subducting plate) has lower
density and is at high pressure.
It rises upwards due to the buoyant force offered by
surrounding denser medium.
62. The magma flows out to the surface.A
continuous upward movement of magma
creates constant volcanic eruptions at the
ocean floor.
Constant volcanism above the subduction zone
creates layers of rocks. As this process
continues for millions of years, a volcanic
landform is created which in some cases rises
above the ocean waters.
Such volcanic landforms all along the boundary
form a chain of volcanic islands which are
collectively called as IslandArcs
63. Example
Formation of the Philippine IslandArc System
Philippine IslandArc system is formed due to subduction of Philippine
Sea plate under the Sunda Plate (major continental shelf of the Eurasian
plate).The trench formed here is called PhilippineTrench
Formation of the IndonesianArchipelago
In the case of IndonesianArchipelago, the Indo-Australian plate is
subducting below Sunda Plate (part of Eurasian Plate).The trench
formed here is calledSunda trench (JavaTrench is a major section of
Sunda trench).
Formation of theCaribbean Islands
TheCaribbean Plate is moving to the east while the NorthAmerican Plate
is moving to the west.
The MarianaTrench or MarianasTrench, the deepest trench, is located in
the western PacificOcean.
The MarianaTrench is formed due to the subduction of the Pacific
Plate below the Mariana Plate.
64. GEOLOGICAL EFFECTS
a zone of progressively deeper earthquakes;
an oceanic trench;
a chain of volcanic islands;
the destruction of oceanic lithosphere.
67. Remember
Oceanic plates are thinner
but denser than
continental plates.
When continental and oceanic plates collide, the
thinner and more dense oceanic plate is
overridden by the thicker and less dense
continental plate.The oceanic plate is forced
down into the mantle in a process known as
"subduction."
68. What happens after the
subduction?
As the ocean floor crust (oceanic plate) loaded with
sediments subducts into the softer asthenosphere,
the rocks in the subduction zone
become metamorphosed (alteration of the
composition or structure of a rock) under high
pressure and temperature.
After reaching a depth of about 100 km, the plates
melt. Magma (metamorphosed sediments and the
melted part of the subducting plate) has lower
density and is at high pressure.
It rises upwards due to the buoyant force offered by
surrounding denser medium.
69. The magma flows out to the surface.
Constant volcanism above the subduction
zone creates layers of rocks.As this
process continues for millions of years, a
volcanic landform is created
Such volcanic landforms all along the
boundary form a chain of volcano which
are collectively called as continental
volcanic arcs
70. EXAMPLES
the Cascade volcanoes along the
Washington-Oregon coast of North
America(Juan de Fuca oceanic plate is subducting
beneath the westward-moving NorthAmerican
continental plate)
The Andes Mountain Range of western South
America (Nazca Plate is subducting beneath the South
American plate.)
Mount Mayon (between Eurasian plate and
Philippineplate
71. GEOLOGICAL EFFECTS
a zone of earthquake activity that is shallow
along the continent margin but deepens
beneath the continent;
an oceanic trench;
a chain of continental volcanic arc;
the destruction of oceanic lithosphere.
72. ….. convergent boundary is
also known as destructive
boundary?
75. TRANSFORM FAULT BOUNDARY
- Transform boundaries are areas where
the Earth's plates move past each other,
rubbing along the edges.
--As the plates slide across from each other,
they neither create land nor destroy it.
Because of this, they are sometimes
referred to as conservative boundaries or
margins.
76.
77. EXAMPLES
TheSanAndreas fault ofCalifornia;
QueenCharlotte Islands fault off western
Canada
Magellanes-Fagnano fault system of South
America.
78. GEOLOGICAL EFFECTS
strike-slip faults can create deep, shallow
earthquakes.
The 2012 Sumatran quake was particularly
powerful; its 8.6 magnitude was the largest
ever recorded for a strike-slip fault.
79. Question:
If "The Big One" happens on the San
Andreas Fault, do we expect a large
tsunami? Do we expect California to
"fall into the ocean”?
No! Earthquakes at transform
boundaries, like the San Andreas fault,
involve hardly any vertical motion. For an
earthquake to generate a tsunami you
need vertical disturbance.
80. Let’s check your understanding on
different types of plate boundary.
Identify the following geological effects to as
what type of plate boundary they were
formed/created.Answer all that apply.
CHOICES
-Oceanic divergence
-Continental Divergence
-OceanicConvergence
-ContinentalConvergence
-Continental-OceanicConvergence
-Transform fault
85. Although many volcanoes form underwater
in subduction zones or at divergent plate
boundaries, some form on land. Areas
where volcanoes that form on land away
from tectonic plate boundaries are known as
hotspots.
88. Let’s check your understanding.
1. In what layer of Earth does a hotspot
volcano start?
a.The core
b.The surface
c. The mantle
d.The crust
89. Let’s check your understanding.
2. How does magma get to the Earth's crust
to create a hotspot volcano?
a.Magma travels to Earth's surface through an
upward tunnel from deep within Earth.
b. Magma is created from asteroids hitting
Earth's surface.
c. Magma is created from meteors hitting
Earth's surface.
d. Magma comes from the sky and drops to the
Earth.
90. Let’s check your understanding.
3. In a hot spot,VolcanoA is on top of the
mantle plume,Volcano B is 10 km farther from
A whileVolcanoC is the farthest.What can
you infer about the ages of the volcanoes?
a.VolcanoA is older thanC
b.VolcanoB is the oldest
c.Volcano B is the youngest
d.Volcano B is younger thanC
91. By: DARYL F.CADANILLA
End of module 1
First quarter
Grade 10 science
