The document provides an overview of earthquakes and faults, detailing the differences between key terms like epicenter, focus, intensity, and magnitude. It describes various types of faults—dip-slip, strike-slip, and oblique-slip—and explains the mechanisms behind earthquake generation, including the release of built-up stress along these faults. Additionally, it covers the relationship between earthquakes and tsunamis, emphasizing the significance of seismic waves in understanding the Earth's subsurface and potential hazards.

1. Earthquakes &
Faults
(Introduction)
Lesson 1:

2. Objectives:
Differentiate the:
1. Epicenter of an earthquake from its
focus;
2. Intensity of an earthquake from its
magnitude;
3. Active and inactive faults.

4. Pacific Ring of Fire
The Pacific Ring of Fire is an arc around the
Pacific Ocean where many volcanoes and
earthquakes are formed.

5. Faults and Earthquakes

6. ■ FAULT: fracture/break in the
Earth’s crust where earthquakes
are most likely to occur.
Many faults occur along plate boundaries.
Faults can also occur anywhere in the crust where
rocks are bent (folded) until they break.
Faults occur as a result of various types of stress.

7. Different Faults Move in
Three Different Ways
Stress - the force applied to rocks.
Tensional - rocks are stretched away from
each other.
Compressional - rocks are pushed toward
each other.
Shear - rockes are pushed toward each other
but not the same axis.

8. HANGING WALL vs FOOTWALL
■ A fault divides rock into two fault blocks
■ For any inclined fault, the block above the fault is
the hanging wall block, and the block below the
fault is the footwall block
www.data.scec.org/Module/footnt02.html

9. Three Types of Faults
1.Dip Slip Fault
2.Strike Slip Fault
3.Oblique Slip Fault

10. CLASSIFICATION of DIP-SLIP FAULTS
■ NORMAL FAULTS: Dip-slip faults on which
the hanging wall moves down relative to
the footwall
• Place younger rocks on older rocks
• Form in regions of lateral extension
www.data.scec.org/
Module/footnt02.html

11. EXAMPLES OF
NORMAL FAULTS
Conjugate Normal Faults,
Canyonlands National Park
darkwing.uoregon.edu/~millerm/conjN1.html Normal Fault Scarps, Turkey
www.msnucleus.org/.../pt/hazards/4/pth4_1a.html
Outcrop scale normal faults

12. CLASSIFICATION of DIP-SLIP FAULTS
■ THRUST or REVERSE FAULTS: Dip-slip faults on
which the hanging wall moves up relative to the
footwall
• Place older rocks on younger rocks
• Form in regions of lateral compression
www.data.scec.org/
Module/footnt02.html

13. EXAMPLES OF
THRUST FAULTS
Thrust Fault in Concrete from 1964 Quake,
Anchorage, Alaska
www.ucmp.berkeley.edu/.../alaska/0709log.html Thrust Fault in Sediments
www001.upp.so-net.ne.jp/fl-fg/05-01.htm
Outcrop scale thrust faults
www.pitt.edu/.../7Structures/ReverseFaults.html

14. CLASSIFICATION of STRIKE-SLIP FAULTS
■ RIGHT-LATERAL (DEXTRAL) FAULTS: Strike-slip
faults across which the block moves to the right
■ LEFT-LATERAL (SINISTRAL) FAULTS: Strike-slip
faults across which the block moves to the right

15. EXAMPLES OF
STRIKE-SLIP
FAULTS
San Andreas Fault, CA
http://education.usgs.gov/california/
pp1515/chapter2/fig2-21.jpg Right Lateral Slip, Izmit, Turkey, 1999 Quake
http://www.geo.uib.no/jordskjelv/
Right Lateral Fault in Asphalt
www.uwsp.edu/.../fault_transform_photo.html

16. OBLIQUE
SLIP FAULTS
A fault which has
a component of
dip-slip and a
component of
strike-slip is
termed an
oblique-slip fault.

17. Difference between focus and epicenter
FOCUS – where the rock
breaks and seismic waves
begin; can be at deep or
shallow depths.
Epicenter – point on the
surface directly above the
focus, usually what is used to
locate the position of an
earthquake.

18. How Do Faults Produce Quakes?
Energy from inside the earth make the ground
move. There is no movement friction right away
because of the friction. Friction held the rocks
together, but once the FRICTION IS OVERCOME,
the ground will move, and the earthquake will occur.

19. Difference between Intensity and Magnitude

21. Active vs Inactive Fault
An active fault is that has
moved in the past and is
expected to move again.
Meaning, it has generated
earthquakes before and is
capable of causing more in the
future. Geologists commonly
consider faults to be active if
there has been movement
observed or evidence of
seismic activity during the last
10,000 years.
Inactive faults are structures that we
can identify, but which do no have
earthquakes. As you can imagine,
because of the complexity of
earthquake activity, judging a fault to
be inactive can be tricky, but often we
can measure the last time substantial
offset occurred across a fault. If a fault
has been inactive for millions of years,
it's certainly safe to call it inactive.
However, some faults only have large
earthquakes once in thousands of
years, and we need to evaluate
carefully their hazard potential.

22. Fault Lines in the Philippines
Fault Lines Affected Areas
1. Marikina Valley Fault Marikina, Montalban, San Mateo, Pasig, Taguig,
Muntinlupa, San Pedro, Biñan, Santa Rosa,
Carmona, Tagaytay, Calamba, Oriental Mindoro
2. Western Philippine Fault Mindoro Strait, Luzon Sea, Sulu Sea, Panay
Gulf
3. Central Philippine Fault The entire Ilocos Norte, Aurora, Quezon,
Masbate, Eastern Leyte, Southern Leyte,
Agusan del Norte, Agusan del Sur, Davao del
Norte
4. Eastern Philippine Fault Philippine Sea
5. Southern Mindanao Fault Celebes Sea as well as the Moro Gulf

26. Role Playing
Make a 2-3 minute role playing act
showing what people do when an
earthquake strikes.

27. HOw you will be scored
Cocept is clear 5
Convincing and
COnsistent
5
Prepared well
and organized
5
Role Play is not
boring
5
20

28. Generalization
An earthquake is a sudden movement
of the earth’s crust caused by the
release of stress accumulated along
geologic faults or by volcanic activity
which can result to destruction of
properties and loss of many lives.

29. For Tomorrow
We will do an activity. Please bring the following.
1. Two sheets of cardboard
2. Fine Sand
3. Ruler
4. Newspaper

30. Objectives:
● Demonstrate how underwater
earthquakes generate tsunamis.
● Explain how earthquake waves
provide information about the
interior of the Earth.

31. Quiz Time:
1. What does the word “tsunami” mean in Japanese?
A. Tidal Wave C. Harbor Wave
B. Century Wave D. Killer Wave
2. What is frequently a warning sign of an impending
tsunami?
A. Seawater suddenly retreats from the shore.
B. Winds suddenly change direction
C. The sky suddenly clears
D. All of the above

32. Quiz Time:
3. What of the subsequent is true about tsunamis?
A. It’s associated with tides
B. It’s a large moving ridge
C. It’s because of the upward movement of rock at the
seafloor
D. It’s because of the upward movement of rock ashore.
4. Which attributes to the vibrations created by an
earthquake?
A. Sea – surface waves C. Seismic Waves
B. Pressure waves D. Tidal waves

33. Quiz Time:
5. Which of the following sequences correctly lists
the different arrivals from first to last?
A. P waves….. S waves…… Surface Waves
B. Surface Waves….. P waves….. S waves
C. P waves….. Surface waves….. S waves
D. S waves….. P waves…..Surface waves

34. Breaking News……..

35. Tsunami (soo.naa.mee)
● Japanese Word:
“tsu” – port of harbor
“nami” – wave
Series of wave in a water body
caused by a displacement of a
large volume of water generally
in an ocean or large lakes.

36. What generate tsunami?
● Earthquakes
● Volcanic Eruption
● Underwater explosions above and below water
Tsunami & Earthquake
Philippines
 Tsunami and Earthquakes can
happen anytime along the Pacific
Ring of Fire

37. Tsunami in the Philippines
● The last measurable tsunami in the Philippines
affected the Northern and Eastern seaboards on 11th
March 2011.

38. Activity 1
● After performing this activity, you should be able to:
1. explain how tsunamis are generated; and
2. infer why tsunamis do not always occur even
when there is an earthquake.
Materials Needed::
 Flat basin or laundry tub (batya)
 Water
 Rectangular piece of plastic panel or plywood or card
 Rock

39. Procedure:
1. Put water in the container. Place the rock in the water
at one end of the container.
2. At the other end of the container, put the plastic panel
flat at the bottom of the container.
3. You will need some help: a person to watch the surface
of the water, and another to watch the level of water
by the rock.
4. Hold the corners of the plastic panel with your thumbs
and fingertips. Wait for the water to stop moving. Using
your fingertips, jerk the edge of the plastic board up.

40. Guide Questions:
1. What was formed in the water by the
sudden push of the plastic panel?
2. How was the water level by the rock
affected by the wave?
3. What does the water represent? How
about the rock?
4. What does the plastic panel represent?

41. Fault
● Fault are found not only on land but also under the sea.

42. Wind waves vs Tsunami waves

43. How Earthquakes related to Tsunamis?

44. Inside the Earth
How Earthquake waves provide information
about the Interior of the Earth?
Seismic Waves – 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 seismograph.

45. Seismic Waves
Seismic Waves radiate from
the focus of an Earthquake.
It can travel in several
ways. There are several
types of seismic waves.
3 Basic Types of Seismic
Waves:
1. P wave
2. S wave
3. Surface Wave

47. P wave & S wave

48. Surface Waves
● Similar to water waves
● Travel under the Earth’s
surface
● They are typically
generated when the source
of the Earthquake is close to
the Earth’ssurface.
● It travel slower that S waves but
they can be much larger in
amplitude and can be the most
destructive of seismic waves.

49. What can Seismic Waves tell us?

52. Good from the Bad?