LESSON 3:
THE FAULT LINES IN THE PHILIPPINES
Fault lines
Affected areas
1. Central Philippine Fault
Entire Ilocos Norte, Aurora, Quezon,
Masbate, Eastern Leyte, Southern
Leyte, Agusan Del Norte, Agusan Del
Sur, Davao Del Norte.
2. Marikina Valley Fault
Montalban, San Mateo, Marikina,
Pasig, Taguig, Muntinlupa, San
Pedro,Binan, Carmona, Santa Rosa,
Calamba, Tagaytay, Oriental Mindoro.
3. Western Philippine Fault
Luzon Sea, Mindoro Strait, Panay
Gulf, Sulu Sea.
4. Eastern Philippine Fault
Philippine Sea
5. Southern of Mindanao Fault
Moro Gulf, Celebes Sea
PHIVOLCS - PHILIPPINE INSTITUTE OF
VOLCANOLOGY AND SEISMOLOGY
Marikina Fault Line – is the most geologically
active fault line in the Philippines.
- it is located in East of Metro Manila and cuts
through all the modern and progressive portions
of Manila, Rizal, Marikina City, Quezon City such
as Eastwood, Rockwell, Ortigas Center, Bonifacio
Global City, Ayala Center, and Alabang.
- it was renamed to West Valley Fault.
Director of Phivolcs
- Director Raymundo Punongbayan
 Why is it he renamed the Marikina Valley
Fault?
- because it caused panic to the
residents of Marikina, as well as most of
the
business
community
within
the
inclusive areas.
Seismologist - said that once the West Valley
Fault Line moved, it can lead to the eruption of
Taal volcano just what happened in June 1990
earthquake when the Central Philippine Fault
moved.
THE CENTRAL PHILIPPINE FAULT
ZONE
PFZ- PHILIPPINE FAULT ZONE
- is a transition zone with slow slip and creep
activity.
 It comprises the Guinyangan Fault, Masbate Fault,
and Central Luzon Fault.
 This is found to be the site and sources of fault
creep activity, slow slip event and great
earthquakes in the archipelago.
 Willis(1937) and Allen(1962)
- studied the PFZ.
- they said that PFZ is comparable to San
Andreas Fault in California because on its geologic
features, faulting and seismic characteristics.
Magnitudes and intensities of earthquakes
Seismograph- can
measure the strength
of an earthquake.
Analyzing a seismogram enables
seismologist to determine the
time, focus, and epicenter, as well
as the amount of energy released
by the movement of the rock
masses.
Magnitude and Intensity- are the
two strength of an earthquake.
Ritcher Scale- designed by Dr. Charles F.
Ritcher of the California Institute of
Technolog.
is
the
best
known
logarithmic scale in measuring the
magnitude( strength of the shock waves)
of earthquakes.
MODIFIED VERSION OF THE RITCHER SCALE
Magnitude
8 and up
General Description
Damage Expected
National
Disaster
Complete
Destruction
7 to 8
Major
Earthquake
Major damage to all
buildings; crust’s
surface cracks
6 to 7
Destructive
earthquake
Collapse of some
structures
5 to 6
Damaging
earthquake
Poorly constructed
buildings are
damaged
4 to 5
Strong
earthquake
Trees broken;
sleepers are
awakened
3 to 4
Small
earthquake
Some fragile are
broken
0 to 3
Tremor
Barely felt, but
sound of tinkling
glass can be heard.
Level of
Instrumental Detected only by Seismograph
Earthquake
I
Instrumental
Detected only by seismograph
II
Feeble
Noticed only by sensitive people
III
Slight
Resembling vibrations caused by heavy traffic
IV
Moderate
Felt by people walking; rocking of free-standing objects
V
Rather strong
Sleepers awakened and bells ring
VI
Strong
Trees sway, some damage from overturning and falling objects
VII
Very strong
General alarm, cracking of walls
VIII
Destructive
Chimneys fall and there is some damage to buildings
IX
Ruinous
Ground begins to crack, houses begins to collapse, and pipes reak
X
Disastrous
Ground badly cracked and many buildings are destroyed. There are
some landslides.
XI
Very disastrous
Few buildings remain standing; bridges and railways destroyed,
water, gas, electricity and telephones out of action
XII
Catastrophic
Total destruction; objects are thrown into the air, much heaving,
shaking, and distortion of the ground.
EARTHQUAKE IN THE PHILIPPINES
Pacific Ring of Fire
- where the philippines is located and it is a
series of interconnected seismic plates that
cause earthquakes and volcanic eruptions.
- the country sits on the Philippine plate, which is
sandwiched by the Pacific Plate and Indian Plate.
LIST OF THE MOST POWERFUL EARTHQUAKES
Date
Magnitude
Place
March 06, 2002
6.8
Palimbang in Mindanao
February 15, 2003
6.2
Masbate
November 18, 2003
6.5
Samar
October 08, 2004
6.5
Mindoro
October 04, 2009
6.6
Moro Gulf, Mindanao
July 23, 2010
7.6
Moro Gulf, Mindanao
What are those examples of damages that caused by
earthquakes?
 Earthquakes pose hazards to humans.
 The vibrations can cause the considerable shaking of
the ground.
 Tsunami in its English equivalent means “seismic sea
waves”.
 Thy can be caused by the following phenomena: The
formation of an earthquake: What are they?
 What happen if the two oceanic plates
meet and collide with one another?
 What if the two colliding plates moved?
 What is the energy released?
 When the waves travels and enter
shallower water in the coastal area. What
will happened?
 If the speed of the tsunami is diminished,
but the wave height is increased
drastically. What will be the cause?
ANSWERS:
 The energy stored between them.
 The denser plates subducts and the lighter
plate is up thrusted.
 The energy released is transferred to the
water.
 It begins to increase in heights and produces
a series of rushing waves.
 It can cause destruction of life and of
property by floating debris and the impact of
water.
THANK YOU GEMINI
FOR LISTENING!!!
HAPPY WEEKEND!!!