unit 1 volcanoes, epicenters, and major mountain belts in

Unit 1

Volcanoes, Epicenters, and Major Mountain Belts in the Philippines

Table of Contents

Table of Contents 1

Introduction 3

Essential Questions 4

Review 4

Lesson 1.1: Distribution of Active Volcanoes 5 Objectives 5 Warm-Up 5 Learn about It 6 Key Points 13 Web Links 14 Check Your Understanding 14 Challenge Yourself 15

Lesson 1.2: Earthquake Epicenters 16 Objectives 16 Warm-Up 16 Learn about It 17 Key Points 23 Web Links 24 Check Your Understanding 24 Challenge Yourself 25

Lesson 1.3: Mountain Belts in the Philippines 26 Objective 26 Warm-Up 26 Learn about It 27 Key Points 31 Web Links 31 Check Your Understanding 31 Challenge Yourself 32

Lesson 1.4: Formation of Landforms 33 Objectives 33 Warm-Up 33 Learn about It 34 Key Points 39 Web Links 40 Check Your Understanding 40 Challenge Yourself 41

Laboratory Activity 42

Performance Task 45

Self Check 47

Key Words 47

Wrap Up 48

Photo Credits 49

References 49

Copyright © 2018 Quipper Limited 2

SCIENCE | GRADE 10

Unit 1 Volcanoes, Epicenters, and Major Mountain Belts in the Philippines

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 every day 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 the Philippine Institute of Volcanology and Seismology (PHIVOLCS), there are 23 active volcano and more than 400 mountains in the country.


Essential Questions

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?

Review

● 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 outer core. ○ The thick layer made up of molten rocks covering the center is called

the mantle. The outer solid rock layer is the crust.

● 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.


Lesson 1.1: Distribution of Active Volcanoes

Objectives In this lesson, you should be able to:

● identify the active volcanoes in the Philippines; and ● determine the location and distribution of the volcanoes.

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?

Warm-Up 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 list of active volcanoes in the Philippines.

3. Using a map of the Philippines, pin the cards on the correct location of the volcanoes.


http://www.phivolcs.dost.gov.ph/html/update_VMEPD/vmepd/vmepd/active.htm



Guide Questions: 1. Do you find any similarities in the location of active volcanoes in the

Philippines? 2. Where do you find most of the active volcanoes in the Philippines?

Learn about It

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 tends to move towards or away from each other thus, forming mountains or volcanoes. In the course of volcanic formation, molten rocks or magma makes 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 Pacific Ring of Fire.


The Pacific Ring of Fire is a 40 000-kilometer, a horseshoe-shaped basin that is associated with oceanic trenches, volcanic arcs, and plate movements. This ring includes several volcanoes from the 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 provide the 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 the 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 these molten materials may ascend to the Earth’s surface and are extruded as lava during a volcanic eruption.


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 the 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.


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 sides. 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 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 on 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 on March 2, 2017.

Fig. 6. Mount Bulusan in Sorsogon.

The complete list of the 23 active volcanoes in the Philippines according to PHIVOLCS is listed in the 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 Laguna, Quezon 2.169 3 1843

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, Tarlac, and Zambales

1.445 3 July – August 1992


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 the 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

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.

Key Points

● 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)


Web Links

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

Check Your Understanding

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. A volcanic eruption is the extrusion of lava and gas from the volcanic vent. 3. Caldera is formed when a volcano collapses 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


https://www.youtube.com/watch?v=wJS7hGMr0Ws

https://www.youtube.com/watch?v=wJS7hGMr0Ws

http://factsanddetails.com/southeast-asia/Philippines/sub5_6h/entry-3167.html

http://factsanddetails.com/southeast-asia/Philippines/sub5_6h/entry-3167.html

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. Didicas Volcano 2. Kanlaon Volcano 3. Calayan Volcano 4. Mt. Bulusan 5. Canipo Volcano

6. Mt. Bontes 7. Mt. Banahaw 8. Mt. Hibok-hibok 9. Biliran Volcano

10. Mt. Burgos

Challenge Yourself

Answer the following questions.

1. What is 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.

Does 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?


Lesson 1.2: Earthquake Epicenters


● define fault, earthquake, and epicenter; ● learn the location of major faults in the Philippines; and ● describe the seismic activities in the country.

Every day, 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?

Warm-Up

Earthquake Simulation

Materials:

● soil ● two shallow containers or shoebox ● small pieces of wood or toy block

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.

2. Put the containers close together and move it in 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?

Learn about It

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 the fault plane and the location below Earth’s surface where the earthquake originates 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 a 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 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 the 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 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.


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 15th 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.


Fig. 10. Distribution 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


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 sand boils which refers to the combination of sand and water that come out from the ground during an earthquake due to 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.


On 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, the 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).

Key Points

● An earthquake 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 originates 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


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 in knowing the effects of a powerful earthquake a country? DOST PHIVOLCS. 2017. ‘Earthquakes and their 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 fractures in the Earth’s crust where rocks move or slide past one

another. 5. The surface where the slips occur. 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 true 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.


http://vm.observatory.ph/geophys_maps.html

http://vm.observatory.ph/geophys_maps.html

https://www.youtube.com/watch?v=Py9k7dacoKo

https://www.youtube.com/watch?v=Py9k7dacoKo

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.

Challenge Yourself

Answer the following questions.

1. What are the two ways of measuring the strength of earthquakes? 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?


Lesson 1.3: Mountain Belts in the Philippines

Objective In this lesson, you should be able to:

● identify the different mountain ranges in the Philippines and their locations.

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 of faults. But what would it look like if there were no mountains formed in the Philippines?

Warm-Up 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.


Guide Questions: 1. Where do you find most of the mountains in the Philippines? 2. Do you find any similarities in the location of active volcanoes and mountains

in the Philippines?

Learn about It

Mountains are usually formed by different geological processes like the movement 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 have 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 the 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 and the third highest in the whole archipelago.

Fig. 12. Relief 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 orogens 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 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.


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.


Key Points

● Groups of these mountain ranges that are similar in form, structure, and alignment are called mountain belts.

● An ophiolite 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.

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 importance 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/the-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 4. Mt. Pinatubo 5. Mt. Negron

6. Mt. Kalatungan 7. Mt. Dulang-dulang 8. Mt. Cuadrado 9. Mt. Cetaceo

10. Mt. Tapulao


https://www.youtube.com/watch?v=drCg4ruJCfA

http://www.hr.undp.org/content/croatia/en/home/presscenter/articles/2014/12/11/the-importance-of-mountains-for-our-sustainable-future.html



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 the Sierra Madre with the Cordillera Central. 6. The highest peak of Kitanglad Mountain Range is Mount Hibok-hibok. 7. The 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.

Challenge Yourself

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 the mountains? 5. Make a list of the names of mountains or mountain ranges in your province.

Provide specific coordinates.


Lesson 1.4: Formation of Landforms


● describe the formation of landforms in the Philippines; and ● be familiar with the plate boundaries surrounding the country.

Every time 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?

Warm-Up Building Landforms with Clay Materials:

● modeling 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?


Learn about It

The formation of several landforms in the country lies in the concept of plate tectonics. The plate’s constant motion and interaction with each other produce 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 the 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. Major plates and plate boundaries.


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 the formation of volcanoes and mountains.

● A divergent boundary is formed when two plates move away from each other resulting to an 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 the 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 Three types of plate boundaries.

One example of the landform produced by a divergent boundary is a new ocean floor. A good example would be the Atlantic Ocean which was formed by the 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. Formation 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.


● 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. Three 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


arc or island arc. Some examples are Indonesia, Japan, and the Philippines.

● When two continental plates converge, it produces a 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.


Fig. 22. Seismic hazard and relative motion of the Philippine Sea Plate.

Key Points

● 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 the descending plate sinks below the other plate.

● Divergent boundary creates a new oceanic crust.


Web Links


● Watch this video for a 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 an intermediate-sized plate.

Write MP if it is a major tectonic plate or IP if it is an intermediate-sized plate.

1. Australian-Indian Plate 2. Nazca Plate 3. Arabian Plate 4. Pacific Plate 5. Antarctic Plate

6. Eurasian Plate 7. Cocos Plate 8. North American Plate 9. African Plate

10. 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.


https://www.youtube.com/watch?v=Xzpk9110Lyw

https://www.youtube.com/watch?v=Xzpk9110Lyw

https://www.livescience.com/37706-what-is-plate-tectonics.html

https://www.livescience.com/37706-what-is-plate-tectonics.html

7. The lithosphere is located down below the asthenosphere. 8. The lithosphere consists of the uppermost mantle and the overlying crust. 9. The 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.

Challenge Yourself

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 is the island arc at the eastern part of the Philippines formed?


Laboratory Activity

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 occurred last January 2018; and

● describe the trend of earthquakes based on the graph. Materials and Equipment

● laptop with spreadsheet ● earthquake list (as of January 2018)

Procedure

1. Obtain a list of earthquakes occurred 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)


http://www.phivolcs.dost.gov.ph/html/update_SOEPD/EQLatest.html

http://www.phivolcs.dost.gov.ph/html/update_SOEPD/EQLatest.html

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 occurred 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 occurrence b. Number of occurrence 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


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?

Performance Task

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 is 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!


Standards and Criteria for Success Your performance will be graded by the following rubric.

Criteria Below Expectations, 0% to 49%

Needs Improvement

50% to 74%

Successful Performance 75% to 99%

Exemplary Performance

100%

Content. Detailed facts are presented well. Contents are related to the task

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 the task.

Details are presented in an organized manner. Content are related

Details are presented in an organized matter that can be easily understood. Content is related to the task. Additional supporting details are presented.

Communication Skills. The presentation was done in a clear and logical manner.

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.

Integrating concepts on earthquake formation and its distribution in the Philippines. Subject matter is integrated and properly used in presenting facts.

No concepts on earthquake formation and its distribution in the Philippines was discussed in the task.

The concepts of earthquake formation and its distribution in the Philippines Were mentioned but not integrated in the task.

The concepts of earthquake formation and its distribution in the Philippines were integrated into 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.


Self Check

After studying this unit, can you now do the following?

Check I can…

discuss the occurrence of volcanoes and mountains in the 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.

Key Words

Active volcano It refers to volcanoes that have 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 It is the point on Earth’s surface vertically above the focus of 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 the 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.


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 a 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

Wrap Up

Distribution of Volcanoes, Earthquakes, and Mountain Belts


Photo Credits

Fig. 4. Mt. Mayon aerial photo by Dexbaldon is licensed under CC BY-SA 4.0 via

Wikimedia Commons. Fig. 5. Taal 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=article&id=78&Itemid=500024

References

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, 8th 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=article&id=50&Itemid=86 Hefferan, Kevin, and John O’Brien. 2010. Earth Materials. UK: Wiley-Blackwell.


https://commons.wikimedia.org/wiki/File:Mt._Mayon_aerial_photo.jpg

https://commons.wikimedia.org/wiki/User:Dexbaldon

https://creativecommons.org/licenses/by-sa/4.0/legalcode

http://commons.wikimedia.org/

https://commons.wikimedia.org/wiki/File:Taal_Volcano_aerial_2013.jpg

https://commons.wikimedia.org/wiki/User:TheCoffee



http://commons.wikimedia.org/

Marshak, Stephen. 2009. Essentials of Geology 3rd Edition. New York: W.W. Norton & Company.

MGB (Mines and Geosciences Bureau, Philippines). 2010. Geology of the Philippines, 2ndEdition. MGB, Department of Environment and Natural Resources, Manila

Monroe, James S. and Reed Wicander.2012. The Changing Earth: Exploring Geology

and evolution, 6th Edition, International Edition. United States: Brooks Cole Publishing

Philippine Institute of Volcanology and Seismology. 2017. “Various Articles”.

Accessed April 27. 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 Journal 1, (March 2008), 7 – 17


http://www.phivolcs.dost.gov.ph/

unit 1 volcanoes, epicenters, and major mountain belts in

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