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Science Grade 10 Unit 1:Volcanoes, Epicenters, and Major Mountain Belts in the Philippines LESSON 1.1 Distribution of Active Volcanoes Table of Contents Introduction...

Science Grade 10 Unit 1:Volcanoes, Epicenters, and Major Mountain Belts in the Philippines LESSON 1.1 Distribution of Active Volcanoes Table of Contents Introduction 1 Learning Competency 2 Learning Objectives 2 Warm-Up 2 Learn about It 3 The Pacific Ring of Fire 3 Volcanic Activities 5 Active Volcanoes 7 Potentially Active Volcanoes 11 Inactive Volcanoes 12 Key Points 13 Check Your Understanding 14 Photo Credits 15 Bibliography 15  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Lesson 1.1 Distribution of Active Volcanoes Mount Pinatubo is one of the active volcanoes found in the Philippines. Introduction The Philippines is an archipelago blessed with beautiful natural landforms that include dormant and active volcanoes. Despite its aesthetic value, the presence of volcanoes in every region of the country poses a high risk to disasters such as earthquakes. In fact, earthquakes due to volcanic activities are very common in the country. Have you ever wondered why there are so many volcanoes in the Philippines? 1  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Learning Competency At the end of this lesson, the given enabling competency should be met by the students: Describe and relate the distribution of active volcanoes, earthquake epicenters, and major mountain belts to plate tectonic theory. Learning Objectives In this lesson, you should be able to do the following: Identify the active volcanoes in the Philippines. Determine the location and distribution of the volcanoes. Warm-Up Mapping the Volcanoes in the Philippine Materials list of active volcanoes in the Philippines map of the Philippines pins Procedure 1. Form a group with a maximum of five members. 2. Using the link below, go to "active volcanoes". Choose five volcanoes from the list of active volcanoes. 2  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines DOST-PHILVOLCS, ‘Volcanoes of the Philippines,’ https://www.phivolcs.dost.gov.ph/index.php/volcano-hazard/volc anoes-of-the-philippines 3. Using the pins, find the correct location of your chosen volcanoes in the Philippine map. Guide Questions 1. How many active volcanoes are known in the Philippines? __________________________________________________________________________________________ __________________________________________________________________________________________ 2. From the list of active, inactive, and dormant volcanoes in the Philippines, how many volcanoes are familiar to you? What are those? __________________________________________________________________________________________ __________________________________________________________________________________________ 3. What region in the Philippines are the active volcanoes usually found? __________________________________________________________________________________________ __________________________________________________________________________________________ Learn about It Essential Questions Why are there numerous volcanoes in the Philippines? How were they formed? 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 3  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines formation, molten rocks or magma make their 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. 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 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 in highly active seismicity and volcanism in the country. Fig. 1. The Pacific Ring of Fire 4  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Volcanic Activities 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. The 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. They are formed through the subduction of an oceanic tectonic plate under another tectonic plate. Subduction of an oceanic plate causes it to go deeper, causing an increasing pressure to act on it. This increasing pressure squeezes water out of the oceanic plate, thereby affecting the melting point of the mantle. The partial melting of the mantle causes magma to ascend and form an arc of volcanoes parallel to the subduction zone. There are two types of volcanic arcs — continental volcanic arc and island volcanic arc. Continental volcanic arcs are formed when an oceanic plate subducts underneath a continental crust, thereby causing magma to rise and form a series of volcanoes along the edge of the continent. On the other hand, when an oceanic plate subducts underneath another oceanic plate, this causes magma to rise and form a whole series of volcanic islands to pop out in the ocean. This process leads to the formation of an island volcanic arc. 5  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Fig. 2. Formation of continental volcanic arc (left) and island volcanic arc (right). Essential Question Where are the active volcanoes in the Philippines located? Fig. 3. Distribution of active and potentially active volcanoes in the Philippines 6  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines 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. Active Volcanoes Active volcanoes are those that erupted within the last 10 000 years. This can be indicated by historical reports or radiometric dating. As of 2008, the Philippine Institute of Volcanology and Seismology (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. 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 volcanoes commonly characterized by a conical shape, a nearly symmetrical structure with a steep summit, and more gradually sloping sides. Mayon Volcano’s last eruption activity was a lava dome growth in January 2018. Fig. 4. Mayon Volcano located in Albay, Philippines 7  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Another active volcano being monitored by PHIVOLCS is the 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. The main crater lake of Taal Volcano is 1.9 kilometers in diameter and is 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. However, it is actually jus one of the many craters of Taal called Binintiang Malaki. The Taal caldera is 25 kilometers across and within it is Taal Lake, which has an area of 267 km2 and is located 2 meters above sea level. There are a total of 47 craters and four maars on the Taal Volcano Island. The most recent activity of this volcano was the sulfur dioxide emission noted last January 2022. Fig. 5. Taal volcano located in Batangas 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 activities were the volcanic earthquakes and very shallow tornillo signals associated with magmatic gas observed on January 2022. 8  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Fig. 6. Mount Kanlaon located in Negros Oriental 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 a weak phreatic eruption recorded on June 11, 2022. Fig. 7. Mount Bulusan in Sorsogon 9  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines The complete list of the 23 active volcanoes in the Philippines according to PHIVOLCS is listed in the table below. Table 1.1.1. Active volcanoes in the Philippines No. of Name of Elevation Latest Eruption/ Province Historical Volcano (km) Activity Eruptions 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 Cagayan 0.712 1 1857 Babuyanes Cagayan Didicas (Babuyan Island 0.843 6 January 1978 Group) September 1948– Hibok-hibok Camiguin 1.332 5 July 1953 Iraya Batanes 1.009 1 1454 Iriga Camarines Sur 1.143 2 January 1642 10  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Kanlaon Negros Oriental 2.435 30 June 2016 (Malaspina) Leonard Davao del Norte 0.200 No Data 1800 years ago Kniaseff Makaturing Lanao del Sur 1.940 10 1882 Matutum Cotabato 2.286 1 March 1911 Mayon Albay 2.460 51 January 2018 Musuan Bukidnon 0.646 2 1867 Parker Cotabato 1.784 1 January 1641 Boundaries of Pinatubo Pampanga, Tarlac, 1.445 3 July–August 1992 and Zambales Ragang Cotabato 2.815 8 July 1916 Cagayan (Babuyan Smith 0.688 5 1924 Island Group) Taal Batangas 0.311 33 January 2020 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. 11  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Table 1.1.2. 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 Tigaon, Tinangis, Mayangayanga, Sta. Cruz, Isarog Camarines Sur V Goa, Simra, Laon, Turat, Pinaglabanan, Abucayan, Tagongtong, Buyo Lapac Sulu ARMM Siasi (Brgy. Sibaud) Bagacay, Lipata, Dampulan, Tigui, Malindig (Marlanga) Marinduque IV Malibago, Sihi Mandalagan Negros Occidental VI Bacolod City Mariveles Bataan III Mariveles, Limay, Orion, Bagac Negron Zambales III Angeles City, Olongapo City Kinabuhayan, Kanluran Laguna, Quezon, San Cristobal IV Napapatid, Abo, Kanluran San Pablo City 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 12  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines 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 La Union, Burgos in Nueva Ecija, Calayan in Cagayan, and Canipo in Palawan. Did You Know? Despite its majestic beauty, Mayon Volcano is said to be the most dangerous active volcano in the Philippines. The worst Mayon eruption ever recorded was on February 1, 1814. The eruption destroyed the villages of Albay and Camarines provinces, including the famous Cagsawa Church. The tragedy claimed a total of 1 200 lives. 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 the Pacific Ring of Fire. About 23 out of the 220 volcanoes in the Philippines are active according to the Philippine Institute of Volcanology and Seismology (PHIVOLCS). Some of the active volcanoes include Mt. Mayon (Albay Province), Mt. Taal (Batangas), Mt. Kanlaon (Negros Oriental), and Mt. Bulusan (Sorsogon). 13  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines Check Your Understanding A. 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. The latest activity of Bulusan Volcano is characterized by a weak phreatic eruption. 3. Binintiang Malaki is one of the 47 craters of Mt. Taal. 4. Taal Volcano is an example of a volcanic caldera and is considered 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. Mt. Mayon is considered to the most active volcano in the Philippines. 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 on Camiguin Island. 10. Mt. Apo is a potentially active volcano in the Davao Region. B. Identify whether each of the following 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 6. Mt. Bontes 2. Kanlaon Volcano 7. Mt. Banahaw 3. Calayan Volcano 8. Mt. Hibok-hibok 4. Mt. Bulusan 9. Biliran Volcano 5. Canipo Volcano 10. Mt. Burgos 14  Science Grade 10 Unit 1: Volcanoes, Epicenters, and Major Mountain Belts in the Philippines 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. Bibliography Carlson, Diane H. and Charles C. Plummer. 2009. Physical Geology: Earth Revealed, 8th Edition. New York: McGraw-Hill Companies, Inc. Hefferan, Kevin, and John O’Brien. 2010. Earth Materials. United Kingdom: Wiley-Blackwell Publishing. Levin, Harold L. 2013. The Earth Through Time. United States of America: John Wiley & Sons Inc. Marshak, Stephen. 2009. Essentials of Geology 3rd Edition. New York: W.W. Norton & Company. Stephen J. Reynolds, et al. 2013. Exploring Geology, 3rd Edition. United States: McGraw-Hill Companies, Inc. Tarbuck, Edward J., and Frederick J. Lutgens. 2015. Earth Science. New Jersey: Pearson Prentice Hall. 15