Unit 1
Volcanoes, Epicenters, and Major
Mountain Belts in the Philippines
Table of Contents
Introduction
3
Essential Questions
4
Review
4
Lesson 1.1: Distribution of Active Volcanoes
5
Objectives
Warm-up
Learn about It
Key Points
Web Links
Check Your Understanding
Challenge Yourself
Lesson 1.2: Earthquake Epicenters
Objectives
Warm-up
Learn about It
Key Points
Web Links
Check Your Understanding
Challenge Yourself
Lesson 1.3: Mountain Belts in the Philippines
Objective
Warm-up
Learn about It
Key Points
Web Links
5
5
6
13
13
14
15
16
16
16
17
23
24
24
25
26
26
26
27
31
31
Check Your Understanding
Challenge Yourself
Lesson 1.4: Formation of Landforms
Objectives
Warm-up
Learn about It
Key Points
Web Links
Check Your Understanding
Challenge Yourself
31
32
33
33
33
34
39
40
40
41
Laboratory Activity
42
Performance Task
44
Self Check
47
Key Words
47
Wrap up
48
Photo Credits
48
References
49
Copyright ​©​ 2018 Quipper Limited
2
The Philippines is one of the countries in the world with high disaster risk index. It
means that we are vulnerable to different natural hazards like storms, floods, and
most of all seismic activities. Several earthquakes occur everyday but most are
weak and generally cannot be felt by people.
Most of these are caused by fault movements, while some are due to volcanic
activity. Volcanoes and mountains are the most common landforms in the
archipelago. Each landform has unique legendary stories on its origin but scientists
argue that its formation is because of the movement of Earth’s crust. According to
Copyright ​©​ 2018 Quipper Limited
3
the Philippine Institute of Volcanology and Seismology (PHIVOLCS), there are 23
active volcano and more than 400 mountains in the country.
At the end of this unit, you should be able to answer the following questions.
● Why are there numerous volcanoes in the Philippines? How were they
formed?
● What are the major causes of earthquakes in the Philippines?
● Where are the active volcanoes in the Philippines located?
● What is the difference between a mountain and a volcano?
● There are four different layers consisting Earth.
○ The center is the ​inner core which is a layer made up of solid iron and
nickel and is the hottest spot on the planet.
○ The inner core is surrounded by a liquid layer of nickel and iron called
the o
​ uter core​.
○ The thick layer made up of molten rocks covering the center is called
the m
​ antle​. The outer solid rock layer is the c
​ rust​.
The crust is consist of ​tectonic plates ​that according to the ​theory of plate
tectonics​, change shape and position over time due to ​convection currents
beneath the plates.
● Heat fluctuation at the earth’s mantle produces these currents. The ocean
floors are spreading from the center, sinking at the edges, and being
regenerated.
● The constant movement of the plates forms ​ocean basins, mountain
ranges, islands, volcanoes, and earthquakes.
●
Copyright ​©​ 2018 Quipper Limited
4
The Philippines is an archipelago blessed with beautiful natural landforms that
include dormant and active volcanoes. Alongside with the aesthetics value
provided, however, is the high risk of disaster. Earthquakes due to volcanic
activities are very common in the county. It is likely that volcanoes are present in
every region. ​Have you ever wondered why there are so many volcanoes in the
Philippines?
Mapping the Volcanoes in the Philippines
Materials:
● list of active volcanoes in the
Philippines
● map of the Philippines
● pins
Procedure:
1. Divide the groups with a maximum
of five members each.
2. Each group will choose five
volcanoes from the l​ ist of active volcanoes in the Philippines​.
3. Using a map of the Philippines, pin the cards on the correct location of the
volcanoes.
Copyright ​©​ 2018 Quipper Limited
5
Guide Questions:
1. Do you find any similarities on the location of active volcanoes in the
Philippines?
2. Where do you find most of the active volcanoes in the Philippines?
The Pacific Ring of Fire
Earth’s surface is composed of major and minor tectonic plates. These plates
overlying the semi-solid, plastic-like asthenosphere are in constant motion. It tend
to move towards or away from each other thus, forming mountains or volcanoes.
In the course of volcanic formation, molten rocks or magma make its way up to the
surface and fill the spaces between the two colliding plates. The Philippines is in a
zone within the Pacific ocean that covers a collection of moving plate edges forming
a “ring” of volcanoes that cause earthquakes. This region is called the Pacific Ring
of Fire​ or the​ Circum-Pacific belt​.
Fig. 1 ​The​ P
​ acific Ring of Fire.
Copyright ​©​ 2018 Quipper Limited
6
The Pacific Ring of Fire is a 40 000-kilometer, horseshoe-shaped basin that is
associated with oceanic trenches, volcanic arcs, and plate movements. This ring
includes several volcanoes from southern tip of South America, up along the coast
of North America, across the Bering Strait, down through Japan, into New Zealand,
and even closed by several active and dormant volcanoes in Antarctica. Around
75% of the world’s active and dormant volcanoes can be found in this region. The
Philippines is an archipelago surrounded by subducting plates that provides ideal
condition for volcanic formation resulting to highly active seismicity and volcanism
in the country.
Volcanic Activities
Tectonic activity in the Philippines is one of the most active in the world
characterized by a number of earthquakes and active volcanic activities. ​This is due
to the interaction of tectonic plates comprising the archipelago​.
Most active volcanoes in the Philippines are found in volcanic arcs. ​Volcanic arcs
are chains of volcanoes formed by subducting plates. It is formed through the
subduction of an oceanic tectonic plate under another tectonic plate result in the
formation of volcanic arcs. The oceanic plate is saturated with water and thus affect
melting point of the mantle. The subduction of the plates goes deeper which
increases the pressure acting on it. This action eventually results in the lesser water
content of plates. The process will form magma ascends to form an arc of
volcanoes parallel to the subduction zone. They are two forms of the volcanic arc
that can be formed. When oceanic crust subducts beneath another oceanic crust
on an adjacent plate creates oceanic arc while continental arcs is formed when
oceanic crust subducts beneath continental crust on an adjacent plate, creating an
arc-shaped mountain belt and stratovolcanoes. There are five distinct volcanic arcs
in the Philippines where the volcanically active region can be found, namely: the
Luzon Volcanic Arc, the East-Philippine Volcanic Arc, the Negros-Panay Arc, the
Sulu-Zamboanga Arc, and the Cotabato Arc.
Emission of gases, flowing of lava outside the surface and sudden violent explosive
bursts are some of the characteristics that describe a volcanic activity. Buoyant
molten rock also known as ​magma rises toward the surface, eventually forming a
magma chamber. Some of this molten materials may ascend to the Earth’s surface
and are extruded as l​ ava​ during a v
​ olcanic eruption​.
Copyright ​©​ 2018 Quipper Limited
7
Active Volcanoes
Active volcanoes are those that erupted within the last 10 000 years. This can be
indicated by historical reports or radiometric dating. Examples of few active
volcanoes being monitored by Philippine Institute of Volcanology and Seismology
(PHIVOLCS). As of 2008, PHIVOLCS listed 23 active, 26 potentially active and 281
inactive volcanoes. Out of ​23 active volcanoes, 21 had historic eruptions​. This
number may still increase depending on future tectonic activities. Most volcanoes
in the country are subduction-related although there are few exotic types.
Fig. 2. ​Distribution of active and potentially active volcanoes in the Philippines.
Copyright ​©​ 2018 Quipper Limited
8
Mayon Volcano​, located in Albay, is
the most active volcano in the country.
It is famous because of its almost
perfect cone shape. It is a stratovolcano
with an elevation of 2.46 kilometers
and a base diameter ​of 20 kilometers.
A stratovolcano is one of the three
types
of
volcano
commonly
characterized by a conical shape, nearly
symmetrical structure with a steep
summit and more gradually sloping
side. Its latest eruption activity was a
lava dome growth on January 2018.
Another active volcano being
monitored by PHIVOLCS is ​Taal
Volcano in Batangas. It is a
volcanic caldera composed of
several active volcanic landforms
making it a complex type of
volcano. A ​caldera is a volcanic
landform
associated
with
depression in a circular form and
has a diameter exceeding one
kilometer. Its main crater lake is
1.9 kilometers in diameter and
located 4 meters above sea
level.
It is a popular misconception
that the crater that can be
seen in Tagaytay is the Taal
volcano itself. It is the parent
volcano
of
Taal
called
Binintian Volcano​. The Taal
caldera is 25 kilometers across
and within it is Taal Lake which
has an area of 267 km2 and
Copyright ​©​ 2018 Quipper Limited
9
located 2 meters above sea level. There are a total of 47 craters and four maars in
Taal Volcano Island. The most recent activity of this volcano was noted last April
2011.
Kanlaon Volcano is another active stratovolcano located in Negros Oriental. It is
2.435 kilometers in elevation with a base diameter of 30 kilometers. Its latest
activity was in June 18, 2016 according to PHIVOLCS.
Located in the province of Sorsogon is ​Bulusan ​Volcano​. It is a stratovolcano
formed inside a caldera. It has several craters and fractures along with four
different hot springs adjacent to it. It is 1.599 kilometers in height and has a base
diameter of 15 kilometers. Its latest activity was in March 2, 2017.
Fig. 6. ​Mount Bulusan located in Sorsogon.
The complete list of the 23 active volcanoes in the Philippines according to
PHIVOLCS is listed in table below.
Table 1. ​Active volcanoes in the Philippines.
Name of
Volcano
Province
Elevation
(km)
No. of
Historical
Eruptions
Latest Eruption/
Activity
Babuyan Claro Cagayan
0.843
4
1917
Banahaw
2.169
3
1843
Laguna, Quezon
Copyright ​©​ 2018 Quipper Limited
10
Biliran
Biliran Island
1.340
1
September 1939
Bud Dajo
Sulu
0.62
2
1897
Bulusan
Sorsogon
1.565
18
March 2017
Cagua
Cagayan
1.160
Cabalian
Southern Leyte
2
1907
Camiguin de
Babuyanes
Cagayan
0.712
1
1857
Didicas
Cagayan
(Babuyan Island
Group)
0.843
6
January 1978
Hibok-hibok
Camiguin
1.332
5
September 1948 –
July 1953
Iraya
Batanes
1.009
1
1454
Iriga
Camarines Sur
1.143
2
January 1642
Kanlaon
(Malaspina)
Negros Oriental
2.435
30
June 2016
Leonard
Kniaseff
Davao del Norte
0.200
No Data
1800 years ago
Makaturing
Lanao del Sur
1.940
10
1882
Matutum
Cotabato
2.286
1
March 1911
Mayon
Albay
2.460
51
August 2014
Musuan
Bukidnon
0.646
2
1867
Parker
Cotabato
1.784
1
January 1641
Pinatubo
Boundaries of
Pampanga,
1.445
3
July – August 1992
Copyright ​©​ 2018 Quipper Limited
11
Tarlac and
Zambales
Ragang
Cotabato
2.815
8
July 1916
Smith
Cagayan
(Babuyan Island
Group)
0.688
5
1924
Taal
Batangas
0.311
33
April 2011
Potentially Active Volcanoes
Potentially active volcanoes do not have any historical record of any eruption but
are considered as morphologically young. There are also suspected seismic activity
and documented local ground deformation. Here are some of the potentially active
volcanoes in the country according to PHIVOLCS.
Table 2. ​Some of potentially active volcanoes in the Philippines.
Name of Volcano
Province
Region
Nearby Cities/Towns
Apo
Davao
XI
Kidapawan, Davao City
Corregidor
Bataan
III
Mariveles
Isarog
Camarines Sur
V
Tigaon, Tinangis,
Mayangayanga, Sta. Cruz,
Goa, Simra, Laon, Turat,
Pinaglabanan, Abucayan,
Tagongtong, Buyo
Lapac
Sulu
ARMM
Siasi (Brgy. Sibaud)
Malindig
(Marlanga)
Marinduque
IV
Bagacay, Lipata, Dampulan,
Tigui, Malibago, Sihi
Mandalagan
Negros
Occidental
VI
Bacolod City
Mariveles
Bataan
III
Mariveles, Limay, Orion, Bagac
Copyright ​©​ 2018 Quipper Limited
12
Negron
Zambales
III
Angeles City, Olongapo City
San Cristobal
Laguna, Quezon,
San Pablo City
IV
Kinabuhayan, Kanluran
Napapatid, Abo, Kanluran
Lazaan, Dolores, San Pablo
City
Silay
Negros
Occidental
VI
Cadiz City
Inactive Volcanoes
Inactive volcanoes have not erupted for at least 10 000 years and are not
expected to erupt again in the future. The morphology of these volcanoes was
already modified by weathering and erosion. There are several inactive volcanoes
found in Cotabato but most are unnamed. Few of the named inactive volcanoes in
other areas are Bolod in Sulu, Bontes in Negros Oriental, Burgos in Nueva Ecija,
Calayan in Cagayan, and Canipo in Palawan.
● The Philippines is in a zone within the Pacific ocean that covers a collection of
moving plate edges forming a “ring” of volcanoes and earthquakes called
Pacific Ring of Fire.
● About 23 out of the 220 volcanoes in the Philippines are active according to
the Institute of Volcanology and Seismology (PHIVOLCS).
● Some of the active volcanoes include Mayon (Albay Province), Taal
(Batangas), Kanlaon (​Negros Oriental) and Bulusan (Sorsogon)
Copyright ​©​ 2018 Quipper Limited
13
For further information, you can check the following web links:
● Do you want to know more about the Ring of Fire? You may
view this link
Natural World. 2014. ‘Ring of Fire.’
https://www.youtube.com/watch?v=wJS7hGMr0Ws
● Visit this link to know more facts and details about volcanoes in
the Philippines.
Jeffrey Hays. 2013. ‘Volcano[es] in the Philippines.’
http://factsanddetails.com/southeast-asia/Philippines/sub5_6h/entry-3167.html
A. Modified True or False. ​Write ​true if the statement is correct. If ​false​,
underline the text that makes the statement incorrect and write the correct
word or group of words on top of it.
1. The Pacific Ring of Fire is a 40 000 kilometer, ring-shaped basin that covers
a collection of plate edges.
2. Volcanic eruption is the extrusion of lava and gas from the volcanic vent.
3. Caldera is formed when a volcano collapse into itself.
4. Taal Volcano is an example of a volcanic caldera and is considered as one
of the most active volcanoes in the country.
5. A volcano can be considered inactive if it hasn’t erupted for 5 000 years.
6. The Bulusan Volcano is recorded to have had the latest volcanic eruption in
the country.
7. Mayon Volcano is a stratovolcano found in Naga, Bicol.
8. As recorded, Mt. Pinatubo has the greatest number of volcanic eruptions
with 51 recorded eruptions.
9. Mt. Hibok-Hibok is an inactive volcano found in Camiguin Island.
10. There are 47 craters in Taal Volcano Island
Copyright ​©​ 2018 Quipper Limited
14
B. Identify whether it is an active or inactive volcano. Write ​A for active and ​IA for
inactive. Also identify the region/province where the volcanoes can be found.
1.
2.
3.
4.
5.
Didicas Volcano
Kanlaon Volcano
Calayan Volcano
Mt. Bulusan
Canipo Volcano
6.
7.
8.
9.
10.
Mt. Bontes
Mt. Banahaw
Mt. Hibok-hibok
Biliran Volcano
Mt. Burgos
Answer the following questions.
1. What are the process involved in volcano formation?
2. Which island group has the most active volcanoes? Give also the specific
provinces where they are found.
3. A submarine volcano is a type of volcano located under the sea or ocean. Do
the Philippines have a submarine volcano? Where is it located?
4. Why do some active volcanoes become dormant.
5. Living near volcanoes is very risky however, there are also some advantages.
What benefits can you obtain from a volcano?
Copyright ​©​ 2018 Quipper Limited
15
Everyday, there are records of several seismic activities in the Philippines. It is
always possible that a strong earthquake may hit an area anywhere in the
archipelago. That is why it is essential that we take all precautionary measures to
make ourselves safe and avoid large damages.
Imagine yourself walking in a city with tall buildings, can you tell if these structures
are sturdy and stable? Do you think they are earthquake proof? Buildings that can
withstand high magnitude earthquakes have a broad base, and decreasing size as
the building gets taller. ​Have you wondered what will happen if we experience
strong seismic and the epicenter is in your city?
Earthquake Simulation
Materials:
● soil
● two shallow container or shoebox
● small pieces of wood or toyblock
Procedure:
1. Make a model of the crust and the structures above it using two shallow
containers or shoebox, soil, and toy blocks or small pieces of wood. The first
container will use the soil as the crust while the second container will use toy
blocks.
Copyright ©
​ ​ 2018 Quipper Limited
16
2. Put the containers close together and move it at opposite directions. Observe
how what happened to the structures.
3. Repeat step two, but now move the containers tightly closer to each other.
Guide Questions
1. What happened to the toy blocks or pieces of woods after moving the
containers?
2. How will you describe the behavior of the soil inside the container while it is
moving?
Earthquakes
Earthquakes occur when rocks in the lithosphere rupture or move in order to
release accumulated energy and stress. They commonly occur along plate
boundaries which are made up of many faults​. ​Faults ​are breaks in Earth’s crust
where rocks move or slide past one another. There should be an apparent
displacement for a break or a fracture for it to be considered as a fault.
Rocks along plate boundaries or zones of high stress are either consolidated or
held together by friction. Given enough stress, a fault will overcome the frictional
force, and stressed rocks will rupture to produce a new fault. These events release
incredible amounts of energy creating earthquakes. The surface where the slip
occurs is called a ​fault plane and the location below Earth’s surface where the
Copyright ​©​ 2018 Quipper Limited
17
earthquake originate is called a ​hypocenter​. It is also commonly known as ​focus​.
The surface directly above the hypocenter is the ​epicenter​. Most of the time, it is
the area where the greatest damage takes place during earthquakes.
Fig. 7 ​How to visualize the events leading to an earthquake.
There are two different measures in describing the strength of an earthquake,
namely: intensity and magnitude.
● Intensity is the measure of the degree of shaking experienced in an area.
This description is a combination of what the people felt and the damage
observed in the structures.
● Magnitude​, on the other hand, is a quantitative measurement based on
instruments. It relies on the data from seismic records along with other
techniques to estimate the amount of the energy released.
Faults in the Philippines
The Philippines is comprised of several subduction zones both on its eastern and
western part. These regions are where tectonic plates meet making it responsible
for most of significant earthquakes, terrible tsunamis, and some of the worst
volcanic eruptions in the archipelago. Also, there are some active faults and
trenches where earthquakes frequently occur.
Located in the Eastern part of the country are the East Luzon Trough and Philippine
Trench, while the western region has the Manila Trench, Negros Trench, Sulu
Trench, and Cotabato Trench. The Philippine Fault or Philippine Fault Zone (PFZ), is
Copyright ​©​ 2018 Quipper Limited
18
a 1 200-km fault zone cutting almost the whole archipelago. It transects the
Philippines from Luzon to Mindanao, passing across Bicol and Leyte. PFZ
accommodates the oblique convergence between the Philippine Sea Plate and the
Philippine archipelago. Aside from the Philippine Fault Zone, there are also other
active faults in the country, namely: Valley Fault System or Marikina Valley Fault,
Macolod Corridor, Lubang-Verde Passage Fault System, Mindoro or Aglubang Fault,
Sibuyan Sea Fault, Legaspi Lineament, Tablas Lineament, Mindanao Fault and, and
Offshore Cebu-Bohol faults.
Fig. 8. ​Distribution of many of the active faults and trenches in the Philippines.
Copyright ​©​ 2018 Quipper Limited
19
Seismic Activity in the Philippines
Even though the Philippines is seismically active, historical accounts of earthquakes
only started during the Spanish colonization in the late 15​th century. These
earthquakes are considered as the historical record before the availability of
instruments. However, the instrumentally-derived parameters for earthquakes
started in 1892 onwards.
Fig. 9. ​Seismicity of the Philippines from 1990 to 2006.
As shown in Fig. 9, there are already millions of earthquakes that occurred in the
country. Some of them are either too weak or too deep to be felt, but few have
caused severe damages. However, from time to time, large earthquakes occur in
the country which results in massive damages. Fig. 10 shows the distribution of
strong earthquakes in the Philippines.
Copyright ​©​ 2018 Quipper Limited
20
Fig. 10. D
​ istribution of large earthquakes in the Philippines.
Here are some of the destructive earthquakes in the Philippines according to
PHIVOLCS.
● August 2, 1968​, a ​magnitude of 7.3 and intensity VIII earthquake occurred
in ​Casiguran, Aurora​. Two hundred seventy people died while 261
individuals were reported injured. A six-story building in Binondo, Manila
(Ruby Tower) collapsed instantly while several major buildings in Binondo
and Escolta, Manila were damaged. There were also extensive landslides and
fissures observed in areas near the epicenter.
● March 17, 1973​, a ​magnitude 7.0 ​earthquake occurred in ​Ragay Gulf
located in Bicol Region. Ninety eight houses were totally destroyed by the
earthquake while 270 houses were partially destroyed in Calauag, Quezon.
Other buildings and structures were also damaged by the earthquake like
the Sto. Rosario Catholic Church of Lopez in Quezon as well as the Hondagua
Theater. What was remarkable during this earthquake was the extent of the
Copyright ©
​ ​ 2018 Quipper Limited
21
observable fault trace which reached the barrio of Sumulong, Calauag that is
90 kilometers away from the epicenter.
● August 17, 1976 ​a ​magnitude 7.9 ​earthquake occurred in ​Mindanao​. It
caused a tsunami which devastated 700 kilometers of coastline in Moro Gulf,
north of Celebes Sea. In Region 9, there were 1,440 dead, 909 missing, 7701
injured, and an estimated 49,848 people were left homeless. In Region 12,
3,351 were reported dead, 1,379 missing, 2,227 injured, and an estimated 43,
534 individuals were left homeless. The number of casualties and damages
were the results of two possible reasons: (1) the earthquake occurred just
after midnight when most people were sleeping and (2) a large tsunami
struck the coast from different directions making it difficult for the people to
know where to go. This is considered as the most destructive earthquake in
the country, so far.
● June 14, 1990 a ​magnitude 7.1 earthquake occurred in ​Panay ​at 3:41 PM. It
killed 8 and injured 41 individuals. Its epicenter was in ​Culasi, Antique​. The
largest tremor reported was Intensity VII in Culasi, Antique and Libacao,
Aklan. A number of residential houses, commercial buildings and bridges
were either completely or partially destroyed. In addition, there were also a
2-km long fissure observed in Balete, Aklan as well as landslides and
sandboils which refers to the combination of sand and water that come out
from the ground during an earthquake due to the liquefaction caused by
ground shaking.
● July 16, 1990​, a ​magnitude 7.8 earthquake occurred in ​Luzon as a result of
the movement of the Digdig Fault, a segment of the PFZ. Its epicenter was
located near the town of ​Rizal, Nueva Ecija​. It produced a 125-km long
ground rupture that cut from Dingalan, Aurora to Kayapa, Nueva Vizcaya.
The reported damage to buildings, infrastructures and properties reached a
total of ₱10 billion. Structures directly on top of the fault were completely
destroyed. Areas in Baguio, Cabanatuan in Nueva Ecija, and Dagupan in
Pangasinan were among the most affected areas. More than 1000 people
were killed during the earthquake, mostly as a result of the collapse of
buildings and other structures.
In addition, the following were also included in the list of PHIVOLCS in surface-wave
magnitude (Ms): Ms 6.5 Laoag Earthquake in August 17, 1983; Ms 6.8 Bohol
Earthquake in February 8, 1990; Ms 7.1 Mindoro Earthquake in November 15, 1994;
Ms 5.6 Bohol Earthquake in May 27, 1996; Ms 5.1 Bayugan Earthquake on June 7,
1999; Ms 6.8 Palimbang Earthquake on March 6, 2002; and Ms 6.2 Masbate
Earthquake on February 15, 2003.
Copyright ​©​ 2018 Quipper Limited
22
In February 10, 2017, a ​magnitude 6.7 ​earthquake occurred in Surigao del Norte
located in northeastern Mindanao. The earthquake generated a 4.3-kilometer
rupture in the municipality of San Francisco, Surigao del Norte. The earthquake was
produced by the movement of the Philippine Fault-Surigao segment. The highest
estimated intensity was Intensity VII. Damages to buildings, ports, roads, collapse of
Anao-aon Bridge, liquefaction, as well as earthquake-induced landslides were also
observed.
In addition, two earthquakes also occurred in Mabini, Batangas on ​April 8, 2017​.
The first one occurred at 3:07 PM (​magnitude 5.6​) while the second occurred at
3:09 PM (magnitude 6.0).
● An ​earthquak​e is the shaking of Earth’ surface resulted from the sudden
release of energy due to the movement of tectonic plates
● The point in Earth’s surface where the earthquake originate is called a
hypocenter​. It is also commonly known as ​focus​.
● Directly above the hypocenter located at the surface is the ​epicenter​. Most
of the time, it is the area where the greatest damage takes place during
earthquakes.
● Casiguran Aurora, Ragay Gulf, Mindanao, Panay, and Nueva, Ecija are
areas in the Philippines where the strongest earthquakes occurred with
magnitude < 7.0
Copyright ​©​ 2018 Quipper Limited
23
For further information, you can check the following web links:
● Know the list of earthquake prone areas in the Philippines.
Manila Observatory. 2005. ‘Mapping Philippine Vulnerability to Environmental
Disasters.’ ​http://vm.observatory.ph/geophys_maps.html
● Interested of knowing the effects of a powerful earthquake a
country?
DOST PHIVOLCS. 2017. ‘Earthquakes and its Hazards.’
https://www.youtube.com/watch?v=Py9k7dacoKo
A. Identify the following.
1. It occurs when rocks in the lithosphere rupture or move in order to release
accumulated energy and stress.
2. The point where an earthquake rapture begins.
3. It is where the latest recorded earthquakes in the country took place.
4. These the fractures in the Earth’s crust where rocks move or slide past one
another.
5. The surface where the slips occurs.
6. The measure of the degree of shaking experienced in an area.
7. The quantitative measurement based on instruments.
8. It is where the Ragay Gulf is located.
9. The earthquake that will cause movements on the West Valley Fault. It is
what the PHIVOLCS warns to prepare for.
10. The fault zone cutting almost the whole archipelago.
B. Write t​ rue​ if the statement is correct. Otherwise, write ​false​.
1. The hypocenter is located at the top of the epicenter.
2. The instrumentally-derived parameters for earthquakes started in 1892.
3. The hypocenter and epicenter are the same.
Copyright ​©​ 2018 Quipper Limited
24
4. The most destructive earthquake—having a magnitude of 7.9—occurred in
Luzon.
5. The Intensity of an earthquake is observed through seismological
instruments.
Answer the following questions.
1. What are the two ways of measuring the strength of earthquake? Define
each.
2. What is the Philippine Fault Zone (PFZ) and where is it located?
3. How are earthquakes produced during plate movement?
4. What are the possible effects if an earthquake with magnitude 7.0 hits Metro
Manila?
5. Locate the West Valley fault in the Philippine map. What areas might be
affected if the fault moves?
Copyright ©
​ ​ 2018 Quipper Limited
25
In Filipino culture, the formation of mountains is often associated with myths and
legends. Based on stories, mountains are protected with enchanted creatures. It is
sometimes the reason why some parts of the vast mountains were remained
almost untouched. It is a fact that mountains provide a lot of benefits to people. It
is the source of food, clean water, and shelter for most of us. It serves as protection
and barrier during typhoons. Mountains can be found all over the archipelago
because of the presence faults. ​But what would it look like if there were no
mountains formed in the Philippines?
Mapping the Mountains in the Philippines
Materials:
● list of mountains in the Philippines
● map of the Philippines
● pins
Procedure:
1. Divide the groups with a maximum of five members each.
2. Search on the web a list of mountains in the Philippines with coordinates.
3. Each group will choose ten mountains from the list.
4. Using a map of the Philippines, pin the cards on the correct location of the
mountains.
Copyright ​©​ 2018 Quipper Limited
26
Guide Questions:
1. Where do you find most of the mountains in the Philippines?
2. Do you find any similarities on the location of active volcanoes and
mountains in the Philippines?
Mountains are usually formed by different geological processes like the movements
of tectonic plates. These landforms are present all over the Philippine archipelago.
Groups of these mountain ranges that are similar in form, structure and alignment
are referred to as ​mountain belts​. The country is comprised mostly of
mountainous regions with narrow to extensive coastal lands. The highest point is
Mt. Apo at 2 954 m above sea level. The mountain belts in the country have tropical
vegetation but has no alpine peaks such as those found in Indonesia and Malaysia
since the highest mountain in the country, Mt. Apo, does not reach the required
elevation to acquire alpine conditions.
Mountain
Ranges
in
the
Philippines
The most prominent range in the
country is ​Central Cordillera​, the
central mountain chain of Luzon
which cuts across the north to the
Luzon Strait from the northern
boundary of the central plain. The
Central Cordillera is an orogen. ​An
orogen is ​a belt of Earth’s crust
involved in mountain formation
caused by the compression of
ancient sedimentary and igneous
terranes. It encompasses the
provinces
of
Cordillera
Administrative Region including portions of Ilocos Norte, Ilocos Sur, La Union,
Pangasinan, Nueva Vizcaya and Cagayan. It is considered as one of the highest
mountain ranges in the country. The highest peak is ​Mt. Pulag which reaches an
elevation of 2,922 meters. It is also considered as the highest mountain in Luzon
Copyright ​©​ 2018 Quipper Limited
27
and the third highest in the whole archipelago.
Fig. 12. R
​ elief map of the Philippine and its mountain ranges.
The ​Sierra Madre Mountain
Range is the longest mountain
range in the country. It is one of
the
oldest
orogen
in
the
archipelago. It runs in the
north-south direction from the
provinces of Cagayan to the north
and Quezon to the south. It covers
the areas of Aurora, Bulacan,
Cagayan, Isabela, Nueva Ecija,
Nueva Vizcaya, Quezon, Quirino,
and Rizal province. The range’s
highest point is still unclear since
Copyright ​©​ 2018 Quipper Limited
28
several peaks are considered as the highest. For example, Mount Anacuao in
Aurora has a height of 1 850 meters while Mount Cetaceo in Cagayan has the same
altitude as well. In April 2012, Mount Guiwan in Nueva Vizcaya had a preliminary
measurement of 1 915 meters on the summit.
The ​Caraballo Mountains connect
Sierra Madre Mountain with the
Central Cordillera. The mountain
range is located in the province of
Nueva Vizcaya. It serves as the
location of the headwaters of
Cagayan River which is the longest
river in the country. This mountain
range reaches an altitude of 1 680
meters.
The ​Zambales Mountains lies on
the western island of Luzon. It is an
ophiolite​, an abducted slice of
oceanic crust emplaced during
subduction. It separates Luzon’s
central plain from the South China
Sea. It extends from western
Pangasinan province, the whole
length of Zambales, to the tip of the
Bataan Peninsula in the south. Its
most noticeable feature is the
Cabusilan
Mountain
Range
comprised of Mt. Pinatubo, Mount
Negron, and Mount Cuadrado.
These mountains are believed to be
volcanic in origin, but the only
active volcano in the mountain
range is ​Mt. Pinatubo​. Its highest
peak is ​Mt. Tapulao with a height
of 2 037 meters.
The longest mountain range in Panay Island is the ​Central Panay Mountain
Range​, also known as the ​Antique Range​. It cuts across the center of Panay Island.
Copyright ​©​ 2018 Quipper Limited
29
Its highest point is Mount Madjaas with an elevation of about 2 100 meters above
sea level.
In the central portion of the
province
of
Bukidnon
lies
Kalatungan Mountain Range​. This
mountain range is situated in
Northern Mindanao. Its highest
peak is ​Mount Kalatungan which
reaches a height of 2 824 meters.
This mountain range is also where
the major river systems in
Bukidnon originate.
Neighboring
the
Kalatungan
Mountain Range is the ​Kitanglad
Mountain Range​. It is located in
the northern central part of
Bukidnon province. Its highest
peak is Mount Dulang-dulang at an
altitude of 2,941 meters. It is also
where the headwater catchment
areas of several major river
systems in the north and central
Mindanao are located. Along with
Kitanglad,
these
rivers
are
considered as protected areas by
the Philippine government.
Pantaron Mountain Range is
considered
as
the
​Central
Cordillera of Mindanao​. It is also
an orogen. It passes through the provinces of Misamis Oriental, Bukidnon, Agusan
del Norte, Agusan del Sur, Davao del Norte and Davao del Sur. Headwaters of
Mindanao River, Pulangi River and Davao River originate from this mountain range.
Copyright ​©​ 2018 Quipper Limited
30
● Groups of these mountain ranges that are similar in form, structure and
alignment are called​ mountain belts.
● An o
​ phiolite​ separates Luzon’s central plain from the South China Sea
● The most prominent range in the country is ​Central Cordillera Mountain
Range​, the central mountain chain of Luzon which cuts across the north to
the Luzon Strait from the northern boundary of the central plain.
For further information, you can check the following web links:
● Do you want to know about the world’s longest mountain
range?
User:Worldswonders. 2010. ‘Himalayas - World's largest mountain range.’
https://www.youtube.com/watch?v=jFC4yD5EgGs
● Know more about the important of mountains by visiting this
link.
United Nations Development Programme. 2014. ‘The importance of mountains for
our sustainable future.’
http://www.hr.undp.org/content/croatia/en/home/presscenter/articles/2014/12/11/t
he-importance-of-mountains-for-our-sustainable-future.html
A. Indicate the location of each given mountain and write the name of the
mountain range where it belongs.
1. Mt. Negron
2. Mt. Pulag
3. Mt. Guiwan
Copyright ​©​ 2018 Quipper Limited
4. Mt. Pinatubo
5. Mt. Negron
6. Mt. Kalatungan
31
7. Mt. Dulang-dulang
8. Mt. Cuadrado
9. Mt. Cetaceo
10. Mt. Tapulao
B. Modified True or False​. Write ​true if the statement is correct. If ​false​, underline
the text that makes the statement incorrect and write the correct word or group
of words on top of it.
1. The Sierra Madre is the most prominent range in the country.
2. Orogeny is a process in which a section of the earth’s crust is crumpled and is
pushed upwards by lateral compression, forming a mountain range.
3. Mt. Pulag is the highest mountain in Luzon.
4. Mt. Apo, being the highest mountain in the country, acquires alpine
conditions.
5. Caraballo Mountains connect Sierra Madre with the Cordillera Central.
6. The highest peak of Kitanglad Mountain Range is Mount Hibok-hibok.
7. Sierra Madre is the longest mountain range in the country.
8. Central Panay Island is also known as Antique Range.
9. Mt. Pinatubo is part of Caraballo Mountains, and is the only active volcano in
the mountain range.
10. Kalatungan Mountain Range is considered as the Central Cordillera of
Mindanao.
Answer the following.
1. What is ophiolite? Where is it located in the Philippines?
2. What is an orogen and how is it involved in mountain formation?
3. What is the difference between a volcano and a mountain?
4. What are the benefits you can get from mountains?
5. Make a list of the names of mountains or mountain ranges in your province.
Provide specific coordinates.
Copyright ​©​ 2018 Quipper Limited
32
Everytime you ride a plane, you get a chance to view from above, vast lands and
majestic mountains. Alongside with these natural creations are man-made
structures. Because of our intelligence, resourcefulness, and creativity, we have
altered the natural landscape of our planet. It is easy for us to deconstruct lands
and turn it into buildings or farmlands. Can we also easily create mountains like
we are building towering skyscrapers?
Building Landforms with Clay
Materials:
● modelling clay of different colors
Procedure:
1. Divide the class into groups with a maximum of five members each.
2. The teacher will assign a landform to each group.
3. Using clays of different colors, try to create the landforms in the picture
Guide Questions:
1. How do you think landforms are formed?
2. What are the things needed in order to create landforms in real-life?
Copyright ​©​ 2018 Quipper Limited
33
The formation of several landforms in the country lies on the concept of ​plate
tectonics​. The plate’s constant motion and interaction with each other produces
mountains, volcanoes, and earthquakes.
According to ​plate tectonics theory​, the lithosphere is a strong rigid layer the
uppermost mantle and crust that were broken into several major and minor
segments called ​tectonic plates​. The lithospheric crust is thinnest in the oceans
and thicker in continents. It lies on top of asthenosphere, a weak and ductile region
in the mantle, which allows the lithosphere to move as a separate component.
There are ​seven major tectonic plates which include North America, South
America, Pacific, African, Eurasian, Australian-Indian, and Antarctic plates. In
addition, there are also intermediate-sized plates such as the Caribbean, Nazca,
Philippine, Arabian, Cocos, Scotia, and Juan de Fuca plates. These plates are further
divided into regions then into microplates such as the Sundaland Plate. The edges
of these plates are marked by volcanic and seismic activities which lead to the
formation of spectacular landforms.
Fig. 18. M
​ ajor plates and plate boundaries.
Copyright ​©​ 2018 Quipper Limited
34
Plate Boundaries
There are three main types of plate boundaries, namely: ​divergent, convergent,
and transform fault​. These plate boundaries also mark the occurrence of
earthquakes and formation of volcanoes and mountains.
● A divergent boundary is formed when two plates move away from each
other resulting to upward movement of molten material and formation of
new seafloor. This type of boundary is also called ​constructive margin​. The
ocean floor is a landform produced by a divergent boundary. An example
would be Atlantic Ocean which was formed by the separation of African,
Eurasian, and American continents.
● A ​convergent boundary is formed when two plates move toward each
other. It is also known as a ​destructive margin​. This type of boundary also
marks subduction zones where the denser lithospheric plate, which is the
oceanic lithosphere, descends into the mantle. It is where the oceanic crust is
destroyed and recycled.
● Transform plate occurs when two plates simply slide past each other. It is
also known as the ​transform fault boundary. ​In this type of boundary,
there is no formation or destruction of the new lithosphere. That is why it is
also called a ​conservative margin​. Most of the transform fault boundaries
can be found on the ocean floor, but there are instances where they also
cut across the continental crust.
Fig. 19 T
​ hree types of plate boundaries.
One example of the landform produced by a divergent boundary is a new
oceanfloor​. A good example would be Atlantic Ocean which was formed by the
Copyright ​©​ 2018 Quipper Limited
35
separation of African, Eurasian, and American continents. Molten material rises in a
divergent boundary, where melting occurs due to decompression of hot
asthenosphere as the plates move apart. As the cracking and expansion continue,
more magma is extruded which later on the young oceanic crust. As the spreading
continues, the oceanic crust becomes wider. Older and denser oceanic crust moves
away from the ridges and is recycled in subduction zones.
Fig. 20. F
​ ormation of a new ocean.
In a convergent boundary, volcanoes and mountain ranges can be formed
depending on the type of crust colliding with each other.
● Earthquakes occur in convergent boundaries as the descending plate sinks
below the other plate. Earthquake locations form a planar zone called the
Wadati-Benioff zone, and it usually starts in the oceanic trench and dips at a
steep angle away from the ocean basins. These earthquakes occur at depths
shallower than 70 kilometers caused by the grinding and pushing of the cold,
brittle descending plate against the other plate. This is one of the reasons
why active seismicity is observed in subduction zones.
Copyright ​©​ 2018 Quipper Limited
36
● When the sinking plate starts to melt, the molten and hotter magma slowly
rises. Some of it will reach the surface, erupt through a vent or a fissure, and
eventually produce a ​volcano​.
Fig. 21. T
​ hree types of convergent boundary.
● When continental lithosphere converges with the oceanic lithosphere, the
continental block remains buoyant while the oceanic crust starts to sink into
the mantle. This ​oceanic-continental convergence forms ​continental
volcanic arcs​. A classic example is the Andes Mountains near the Peru-Chile
Trench.
● When two oceanic crusts converge, the denser oceanic block sinks beneath
the other. This ​oceanic-oceanic convergence produces a ​volcanic island
Copyright ​©​ 2018 Quipper Limited
37
arc o
​ r​ island arc​. Some examples are Indonesia, Japan, and the Philippines.
● When two continental plates converge, it produces spectacular mountain
ranges, also known as orogens, such as the Himalayas. This occurs when
rocks in continental plates are folded into linear belts, metamorphosed, and
pushed upward.
Philippine Plate Interactions
The Philippines is composed of many ​island arcs ​and orogens produced by
subduction. Majority of the islands are considered as part of the ​Philippine Mobile
Belt (PMB)​. Several million years ago, the Philippine Sea Plate collided with the
Sundaland Plate, a part of the larger Eurasian plate. The collision resulted in a
complex system of tectonic interactions of the Philippine Sea Plate and the
Sundaland Plate, featuring several subduction zones and orogenies.
In the Western border, the South China Sea, Sulu Sea, and Celebes Sea Basins are
subducting beneath the PMB. These different subductions, along with many others,
resulted in the emergence of island arcs of Luzon, Negros, Sulu, Zamboanga, and
Cotabato.
On the Eastern border, the subduction along the East Luzon Trough and Philippine
Trench resulted in the formation of island arcs of Northern Sierra Madre, Southern
Sierra Madre-Polillo-Catanduanes, and the East Philippine Arc.
On the other hand, the Palawan blocks (North and South Palawan, Mindoro,
Western Panay, Romblon Islands) were said to come from the southeast edge of
the continental crust of China as part of the Eurasian plate. This is also one of the
reasons why Palawan is not seismically active unlike the rest of the Philippines.
Copyright ​©​ 2018 Quipper Limited
38
Fig. 22. S
​ eismic hazard and relative motion of the Philippine Sea Plate.
● There are three main types of plate boundaries namely ​divergent,
convergent, and transform fault​.
● Volcanoes and mountain ranges can be formed in convergent boundaries
depending on the type of crust colliding with each other. Earthquakes occur
when descending plate sinks below the other plate.
● Divergent boundary​ creates new oceanic crust.
Copyright ​©​ 2018 Quipper Limited
39
For further information, you can check the following web links:
● Watch this video for more visual presentation of plate
boundaries
Iris Earthquake Science. 2016. ‘Plate Boundaries & Tectonic Plates.’
https://www.youtube.com/watch?v=Xzpk9110Lyw
● Do you want to have a more detailed knowledge on plate
tectonics?
Live Science. 2017. ‘What is Plate Tectonics’
https://www.livescience.com/37706-what-is-plate-tectonics.html
A. Identify whether it is a major tectonic plate or a intermediate-sized plate. Write
MP​ if it is a major tectonic plate or I​ P​ if it is an intermediate-sized plate.
1.
2.
3.
4.
5.
Australian-Indian Plate
Nazca Plate
Arabian Plate
Pacific Plate
Antarctic Plate
6.
7.
8.
9.
10.
Eurasian Plate
Cocos Plate
North American Plate
African Plate
Caribbean Plate
B. Modified True or False​. Write ​true if the statement is correct. If ​false​,
underline the text that makes the statement incorrect and write the correct
word or group of words on top of it.
1. There are eight major tectonic plates.
2. The lithospheric crust is thicker in continents than in oceans.
3. When a convergent boundary is formed, it can result to a formation of new
seafloor.
4. The convergence of two continental plates produces orogens.
5. Transform plate occurs when two plates simply slide past each other.
6. Divergent boundary is also called constructive margin.
Copyright ​©​ 2018 Quipper Limited
40
7. Lithosphere is located down below the asthenosphere.
8. Lithosphere consists of the uppermost mantle and the overlying crust.
9. Asthenosphere is a weak and ductile region that allows the lithosphere to
move as a separate continent.
10. The Atlantic Ocean is produced by a divergent boundary.
Answer the following questions
1. What is the process involved in volcano formation?
2. In what type of boundary can you observe crust formation? Explain the
process of crust formation.
3. What is the plate tectonics theory? Describe briefly.
4. How are volcanic arcs formed?
5. How are the island arc at the eastern part of the Philippines formed?
Copyright ​©​ 2018 Quipper Limited
41
Activity 1.1
Graphical Analysis of Earthquakes
Objectives
At the end of this laboratory activity, the students should be able to:
● create a graph showing the trend of earthquakes in the Philippines that
occured last January 2018; and
● describe the trend of the earthquakes based of the graph.
Materials and Equipment
● laptop with spreadsheet
● earthquake list (as of January 2018)
Procedure
1. Obtain a list of earthquakes occured last January 2018. ​Take note of the
date, locations and magnitude of the earthquake. You may access the list
from PHIVOLCS using the link below.
● PHIVOLCS Earthquake Bulletins of latest seismic events in the
Philippines are listed on this link.
PHIVOLCS. 2018. ‘Seismological Observation and Earthquake Prediction
Division‘Atomic Structure Timeline.’
http://www.phivolcs.dost.gov.ph/html/update_SOEPD/EQLatest.html
2. Using a spreadsheet, input the gathered data on a table.
Earthquake no.
Magnitude
range*
Location
(Major Island Group**)
1
0-2.5
Abra (Luzon)
2
0-2.5
Ilocos Norte (Luzon)
3
2.5-5.4
Northern Samar (Visayas)
Copyright ​©​ 2018 Quipper Limited
42
Notes:
* In what magnitude range of does the earthquake fall?
● 0–2.4
Usually not felt
● 2.5–5.4
Often felt, but only causes minor damage
● 5.6–6.0
Slight damage to buildings and other structures
● 6.1–6.9
May cause a lot of damage in very populated areas
● 7.0–7.9
Major earthquake. Serious damage
** Identify the major island group (Luzon, Visayas, Mindanao)
3. Count the total number of earthquakes occured in each major island groups.
Also count the total occurrence for each magnitude range.
4. Draw graphs using the chart function of the spreadsheet.
a. Magnitude range and number of occurence
b. Number of occurene per major island group
Data and Results
Table 1​. Earthquakes that happened in the Philippines.
Earthquake no.
Magnitude
range*
Location
(Major Island Group**)
1
2
3
4
5
Copyright ​©​ 2018 Quipper Limited
43
Copyright ​©​ 2018 Quipper Limited
44
Guide Questions
1. What major island group has the most number of earthquakes recorded?
Explain its possible implication
2. What was the strongest earthquake recorded last January 2018? Where was
it located? Implications?
3. How many earthquakes occurred last January 2018? How strong are these
earthquakes?
Distribution Map and Earthquake Awareness
Goal:
● Your group’s goal is to disseminate information about the earthquake
activities occurred in the Philippines in the year 2017, and to give your
audience safety guidelines in case of an earthquake emergency.
Role:
● You are a group of young researchers aiming to spread awareness about
current seismic activities and its implications. You are also going to give the
school guidelines on how to be ready and prepared for earthquake.
Audience:
● Your audience are your schoolmates and the school teachers and staff.
Situation:
● The challenge is to convince your audience to have a survival kit ready and to
be calamity-ready all the time. You will create a brochure containing the
distribution map of 2017 earthquake you made with the information you
have gathered during your research, and the safety precautions you would
like to share to your audience; like the contents of a survival kit and the
things to do before, during and after an earthquake. You will have the
brochures distributed to every classroom in your school. It is always better to
be prepared!
Copyright ​©​ 2018 Quipper Limited
45
Standards and Criteria for Success
Your performance will be graded by the following rubric.
Criteria
Content.
Detailed facts are
presented well.
Contents are related
to the task
Communication
Skills.
Needs
Improvement
50% to 74%
Successful
Performance
75% to 99%
Exemplary
Performance
100%
Details not
presented.
Content is not
related to the task.
Details are
presented but not
organized. There
are some content
that are not
related to task.
Details are
presented in an
organized manner.
Content
are related
Details are
presented in an
organized matter
that can be easily
understood.
Content are
related to the task.
Additional
supporting details
are presented.
Presentation was
not done.
Presentation was
done but in a
disorganized and
illogical manner.
Presentation was
done smoothly but
the concepts are
presented in such
a way that should
be rearranged for
better
understanding.
Presentation was
done clearly.
Concepts were
presented in a
logical manner
and easily
understandable by
the audience.
No concepts on
earthquake
formation and its
distribution in the
Philippines was
discussed in the
task.
The concepts on
earthquake
formation and its
distribution in the
Philippines
Were mentioned
but not integrated
in the task.
The concepts on
earthquake
formation and its
distribution in the
Philippines were
integrated in the
task. Concepts
were properly
presented in
relation to the
task.
The concepts on
earthquake
formation and its
distribution in the
Philippines was
integrated in
an organized and
logical way.
Additional
Concepts related
to the task
were presented.
Below Expectations,
0% to 49%
Presentation was
done in a clear and
logical manner.
Integrating
concepts on
earthquake
formation and its
distribution in
the Philippines.
Subject matter is
integrated and
properly used in
presenting facts.
Copyright ​©​ 2018 Quipper Limited
46
After studying this unit, can you now do the following?
Check
I can…
discuss the occurrence of volcanoes and mountains in Philippines.
describe an earthquake and its effect around its epicenter.
explain the formation of mountain belts.
list down major volcanic eruptions and their location in the
Philippines.
discuss the movement of plates during land formations.
list down examples of mountain belts in the Philippines.
Active volcano
It refers to volcanoes that has had at least one eruption
during the past 10 000 years.
Asthenosphere
It is the upper layer of the mantle just below the
lithosphere.
Epicenter
Is the point on Earth’s surface vertically above the focus
on an earthquake.
Faults
It is a break in the rocks that make up the crust that
moved past each other.
Focus
It is the location where earthquake begins.
Lithosphere
It is the rigid part of Earth consisting of the crust and the
upper mantle.
Mountain belts
It is a group of mountain ranges with similar form,
structure and alignment.
Copyright ​©​ 2018 Quipper Limited
47
Orogen
It is a belt in Earth’s crust involved in the formation of
mountains.
Pacific Ring of Fire
It is a horseshoe shape zone the Pacific Ocean where
large number of earthquakes and volcanic eruptions
occur.
Plate tectonic theory It is a theory that describes the large-scale motion of
seven large plates movements of small plates of the
lithosphere.
Volcanic arc
It is the chain of volcanoes above a subducting plate,
positioned in an arc shape as seen from above
Distribution of Volcanoes, Earthquakes, and Mountain Belts
Copyright ​©​ 2018 Quipper Limited
48
Fig. 4.​ M
​ t. Mayon aerial photo​ by D
​ exbaldon​ is licensed under ​CC BY-SA 4.0​ via
Wikimedia Commons​.
Fig. 5.​ T
​ aal Volcano aerial 2013​ by ​The Coffee (Mike Gonzalez)​ is licensed under ​CC
BY-SA 3.0​ via ​Wikimedia Commons​.
Fig. 8. ​Active Faults and Trenches in the Philippines. Public domain.
http://www.phivolcs.dost.gov.ph/index.php?option=com_content&view=articl
e&id=78&Itemid=500024
Bautista, Maria Leonila P. and Bartolome C. Bautista. “The Philippine historical
earthquake catalog: its development, current state and future directions.”
Anals of Geophysics​, vol. 47 (April/May 2004).
Borlaza, Gregorio C. and Carolina Hernandez. “Philippines” ​Encyclopedia Britannica​.
Last
modified
December
13,
2016.
https://www.britannica.com/place/Philippines
Carlson, Diane H. and Charles C. Plummer. 2009. ​Physical Geology: Earth Revealed​,
8​th​ Edition.​ New York: McGraw-Hill Companies, Inc.
Coenraads, Robert R. 2005. ​Rocks & Fossils: A Visual Guide​. Australia: Weldon Owen
Inc.
DOST-PHIVOLCS. 2008. “PHIVOLCS Volcano Monitoring”. Accessed April 23, 2017.
http://www.phivolcs.dost.gov.ph/index.php?option=com_content&view=articl
e&id=50&Itemid=86 Hefferan, Kevin, and John O’Brien. 2010. Earth Materials.
UK: Wiley-Blackwell.
Marshak, Stephen. 2009. Essentials of Geology 3rd Edition. New York: W.W. Norton
Copyright ​©​ 2018 Quipper Limited
49
& Company.
MGB (Mines and Geosciences Bureau, Philippines). 2010. ​Geology of the Philippines,
2​nd​Edition​. MGB, Department of Environment and Natural Resources, Manila
Monroe, James S. and Reed Wicander.2012. T​ he Changing Earth: Exploring Geology
andEvolution, 6​th Edition, International Edition​. United States: Brooks Cole
Publishing
Philippine Institute of Volcanology and Seismology. 2017. “Various Articles”.
Accessed April27. ​http://www.phivolcs.dost.gov.ph
Tarbuck, Edward J. and Frederick J. Lutgens. 2015. ​Earth Science​. New Jersey:
Pearson Prentice Hall.
Yumul Jr., Graciano P., Carla B. Dimalanta, Victor B. Maglambayan and Edanjarlo J.
Marquez.“Tectonic Setting of a Composite Terrane: A Review of the Philippine
Island Arc System.” 12 ​Geosciences J​ ournal 1, (March 2008), 7 – 17
Copyright ​©​ 2018 Quipper Limited
50