SCIENCE

• Magma rising to Earth's surface

  Can cause movement or deformation of the crust, detected by seismographs
• Detecting movement or deformation of the crust

  Important tool to predict future volcanic eruptions
• Pacific Ring of Fire


  A zone within the Pacific ocean that covers a collection of moving plate edges forming a "ring" of volcanoes that cause earthquakes
• Pacific Ring of Fire

  • A 40,000-kilometer, horseshoe-shaped basin associated with oceanic trenches, volcanic arcs, and plate movements
  • The Philippines is an archipelago surrounded by subducting plates that provides ideal conditions for volcanic formation resulting in highly active seismicity and volcanism

  
• Magma


  Buoyant molten rock that rises toward the surface and is extruded as lava during a volcanic eruption
• Tectonic activity in the Philippines is one of the most active in the world characterized by a number of volcanic activities

  
• Active volcanoes


  Those that erupted within the last 10,000 years

  
• As of 2008, PHIVOLCS listed 23 active volcanoes in the Philippines

  
• Mayon Volcano


  • The most active volcano in the Philippines located in Albay, famous for its almost perfect cone shape
• Taal Volcano


  • A volcanic caldera composed of several active volcanic landforms making it a complex type of volcano

  
• Kanlaon Volcano


  • An active stratovolcano located in Negros Oriental, with latest activity in June 2016

  
• Bulusan Volcano


  • A stratovolcano formed inside a caldera, located in Sorsogon, with latest activity in March 2017

  
• Potentially active volcanoes


  Volcanoes that do not have any historical record of eruption but are considered morphologically young

  
• Potentially active volcanoes in the Philippines

  • Apo (Davao)
  • Corregidor (Bataan)
  • Isarog (Camarines Sur)
  • Lapac (Sulu)
  • Malindig (Marinduque)
  • Mandalagan (Negros Occidental)

  
• Inactive volcanoes


  Volcanoes that have not erupted for at least 10,000 years and are not expected to erupt again in the future, with their morphology modified by weathering and erosion

  
• As of 2008, PHIVOLCS listed 26 potentially active and 281 inactive volcanoes in the Philippines

  
• Earthquake


  Shaking of Earth's surface resulting from the sudden release of energy due to the movement of tectonic plates
• Earthquakes occur when


  Rocks in the lithosphere rupture or move in order to release accumulated energy and stress
• Faults


  • 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

  
• Fault plane


  The surface where the slip occurs
• Hypocenter


  The location below Earth's surface where the earthquake originates

  
• Epicenter


  The surface directly above the hypocenter
• Mountain belts


  Groups of mountain ranges that are similar in form, structure and alignment
• The epicenter is the area where the greatest damage takes place during earthquakes
• Mountains in the Philippines

  • Present all over the Philippine archipelago
  • Country is comprised mostly of mountainous regions with narrow to extensive coastal lands

  
• Mountain formation


  1. Convergent boundaries where two tectonic plates move toward each other

  2. Collision of tectonic plates results in crustal uplift and mountain formation
• Intensity


  The measure of the degree of shaking experienced in an area
• Mountain ranges in the Philippines

  • Tropical vegetation but no alpine peaks such as those found in Indonesia and Malaysia

  
• Magnitude


  A quantitative measurement that relies on the data from seismic records along with other techniques to estimate the amount of the energy released
• Cordillera Central Mountain Range


  • The most prominent range in the country
  • Central mountain chain of Luzon which cuts across the north to the Luzon Strait from the northern boundary of the central plain
• Highest peaks in the Philippines

  • Mt. Pulag (2,922 meters)
  • Mt. Kalatungan (2,824 meters)
  • Mt. Dulang-dulang (2,941 meters)

  
• Active faults in the Philippines

  • East Luzon Trough
  • Philippine Trench
  • Manila Trench
  • Negros Trench
  • Sulu Trench
  • Cotabato Trench
• Sierra Madre Mountain Range

  • The longest mountain range in the country
  • One of the oldest orogen in the archipelago
• Philippine Fault or Philippine Fault Zone (PFZ)


  • A 1,200-km fault zone cutting almost the whole archipelago

  
• Caraballo Mountains


  • Connect Sierra Madre Mountain with the Cordillera Central
  • Location of the headwaters of Cagayan River, the longest river in the country
• Other active faults in the Philippines

  • Valley Fault System or Marikina Valley Fault
  • Legazpi Lineament
  • Macolod Corridor
  • Tablas Lineament
  • Lubang-Verde Passage Fault System
  • Mindanao Fault
  • Mindoro or Aglubang Fault
  • Offshore Cebu-Bohol Faults
  • Sibuyan Sea Fault

  
• Zambales Mountains


  • An ophiolite, an abducted slice of oceanic crust emplaced during subduction
• Cabusilan Mountain Range


  • Comprised of Mt. Pinatubo, Mount Negron, and Mount Cuadrado
• Historical accounts of earthquakes only started during the Spanish colonization in the late 15th century
• Kalatungan Mountain Range


  • Highest peak is Mount Kalatungan at 2,824 meters