An earthquake is natural when the earth’s tectonic plates shift and release energy, creating surface tremors. The Philippines is located in the Pacific Ring of Fire, where tectonic plates clash, making it highly prone to earthquakes.
The Philippines’ placement along significant fault lines, such as the West Valley Fault, enhances the danger of large and potentially devastating earthquakes. The country has already undergone severe earthquakes, and it is critical for citizens to be aware of the risks and to be prepared for these calamities.
Frequency of earthquakes in the Philippines
The Philippines is one of the world’s most seismically active countries, with frequent earthquakes of varied magnitudes. The Philippine Institute of Volcanology and Seismology (PHIVOLCS) records about 20 earthquakes every day or about 7,000 earthquakes per year on average.
Most of these earthquakes are too weak to be felt, but the country is also subjected to many significant earthquakes yearly, which can cause damage and loss of life. The frequency of earthquakes in the Philippines emphasizes the need of earthquake preparedness and the need for citizens to be informed of potential hazards.
Major earthquakes that occurred in the Philippines
The Philippines has experienced several major earthquakes throughout its history. Some of the most significant earthquakes include:
Luzon Earthquake of 1990
Also known as the Baguio City Earthquake, it had a magnitude of 7.7 and caused significant damage and loss of life in Northern Luzon.
Bohol Earthquake of 2013
This earthquake had a magnitude of 7.2 and struck the island of Bohol, causing extensive damage to buildings and infrastructure.
Mindanao Earthquake of 2019
A series of earthquakes with magnitudes ranging from 6.3 to 6.6 struck Mindanao in 2019, causing significant damage and loss of life.
Leyte Earthquake of 2017
This earthquake had a magnitude of 6.5 and struck the island of Leyte, causing damage to buildings and infrastructure.
Luzon Earthquake of 1968
Also known as the Casiguran Earthquake, it had a magnitude of 7.3 and caused significant damage and loss of life in Northern Luzon.
These earthquakes serve as a reminder of the potential risks of living in a seismically active country like the Philippines and highlight the importance of earthquake preparedness.
Causes of earthquakes in the Philippines
As the Philippines is situated along the Pacific Ring of Fire, earthquakes and other geological occurrences, such as volcanic eruptions, are extremely common.
Tectonic plate movement
Most earthquakes in the Philippines are caused by the movement and interaction of tectonic plates beneath the earth’s surface.
The country is also located along several subduction zones, where one tectonic plate is forced beneath another. This process can cause significant energy buildup, leading to strong earthquakes.
The Philippines is home to numerous active volcanoes, and volcanic activity can trigger earthquakes in the surrounding areas.
Some earthquakes in the Philippines may also be caused by human activity, such as mining or the construction of large dams.
Tectonic plates and fault lines that cause earthquakes in the Philippines
Within the Pacific Ring of Fire, some of the major tectonic plates and fault lines that cause tremors in the Philippines include:
The primary tectonic plate underlying the Philippine Islands is the Philippine Plate. It interacts with numerous other plates, including the Pacific, Eurasian, and Australian plates.
The Manila Trench is a subduction zone located to the west of Luzon Island. It marks the boundary between the Philippine and Eurasian Plates and is responsible for several large earthquakes in the region.
Philippine Fault System
This complex network of active fault lines runs throughout the country. It includes several significant fault segments, such as the West Valley Fault, Marikina Valley Fault System, Eastern Mindanao Fault System, and Negros Trench Fault System.
Mindanao Fault System
The Mindanao Fault System is another network of active faults that runs through the island of Mindanao. It is responsible for several regional earthquakes, including the 2019 Mindanao earthquakes.
Overall, the interaction of these tectonic plates and fault systems makes the Philippines highly susceptible to earthquakes, and residents must be prepared for potential disasters.
How is earthquake intensity measured?
Earthquake intensity is measured on a variety of scales. The Modified Mercalli Intensity (MMI) scale, which quantifies the intensity of an earthquake based on its consequences on people, structures, and the environment, is one regularly used scale. The MMI scale spans from I (not felt) to XII (very severe) (total destruction).
The Richter scale, which quantifies the magnitude of an earthquake based on the amplitude of the seismic waves produced, is another extensively used scale. Because the Richter scale is logarithmic, an earthquake with a magnitude of 7.0 is ten times stronger than one with a value of 6.0.
Other scales that are used to measure earthquake intensity include the moment magnitude scale (MMS), the surface wave magnitude (MS) scale, and the moment tensor scale (MT). Each of these scales uses different methods to measure and quantify the intensity of earthquakes.
Impact of earthquakes on lives and properties
Earthquakes can have a significant impact on lives and properties in affected areas.
Loss of life
Earthquakes can result in fatalities due to collapsed buildings, falling debris, and other hazards.
Luzon Earthquake (July 16, 1990)
This 7.8 magnitude earthquake struck the northern part of Luzon Island, resulting in approximately 1,621 deaths.
Bohol Earthquake (October 15, 2013)
This 7.2 magnitude earthquake struck the island of Bohol and resulted in 222 deaths.
Surigao Earthquake (February 10, 2017)
This 6.7 magnitude earthquake struck the island of Mindanao and resulted in 8 deaths.
Mindanao Earthquakes (October 2019)
A series of earthquakes struck the island of Mindanao, including a 6.6 magnitude earthquake on October 29, 2019. These earthquakes resulted in 24 deaths and significant damage to infrastructure.
Even in non-fatal earthquakes, people can sustain injuries from falling objects, broken glass, or other hazards.
Damage to buildings and infrastructure
Earthquakes can cause significant damage to buildings, roads, bridges, and other infrastructure. This damage can be costly to repair and may require long-term reconstruction efforts.
Major earthquakes in the Philippines have caused significant damage to houses and commercial establishments.
Luzon Earthquake (July 16, 1990)
This earthquake caused extensive damage to buildings, particularly in Nueva Ecija, Pampanga, and Pangasinan provinces. Many houses and commercial establishments were destroyed or severely damaged.
Bohol Earthquake (October 15, 2013)
This earthquake caused damage to more than 73,000 houses, as well as schools, hospitals, and other buildings. Many commercial establishments, including malls, markets, and restaurants, were also damaged.
Surigao Earthquake (February 10, 2017)
This earthquake caused damage to more than 4,000 houses and buildings, as well as roads, bridges, and other infrastructure. Many commercial establishments, including hotels, restaurants, and shops, were also damaged.
Mindanao Earthquakes (October 2019)
The earthquakes that struck Mindanao caused significant damage to houses and commercial establishments, particularly in Cotabato and Davao del Sur. Many buildings collapsed or suffered severe damage, including schools, hospitals, and malls.
The damage to houses and commercial establishments can have long-term economic and social impacts, particularly for affected communities. It underscores the importance of earthquake-resistant building design and preparedness and response measures to mitigate the impact of earthquakes on buildings and infrastructure.
Earthquakes can have a significant economic impact, particularly in heavily populated areas. The damage to buildings and infrastructure can result in loss of business and income, and the cost of reconstruction can be substantial.
The economic impact of Philippine earthquakes can be significant, particularly in heavily affected areas.
Damage to infrastructure
Earthquakes can damage roads, bridges, and other infrastructure, which can lead to disruptions in transportation and commerce.
Damage to businesses
Many businesses, particularly small and medium-sized enterprises, can be severely impacted by earthquakes. Damage to buildings and equipment and disruptions to supply chains and markets can lead to lost revenue and profits.
Displacement of people
Earthquakes can lead to the displacement of people from their homes and communities, which can have significant economic impacts. Displaced people may have to rely on government aid or charity to meet their basic needs, which can strain public resources.
Loss of tourism revenue
Earthquakes can also significantly impact tourism, particularly if popular destinations are affected. Damage to hotels, restaurants, and other tourist facilities can lead to lost revenue and jobs.
Overall, the economic impact of earthquakes can be difficult to quantify, as it depends on various factors, including the severity and location of the earthquake and the preparedness and response measures in place. However, earthquakes can have significant economic consequences for affected communities, businesses, and industries, and preparedness and response efforts are essential to minimize these impacts.
The Big One
The name “Big One” refers to the expected earthquake of 7.2 or higher expected to strike the Metro Manila area and adjacent provinces in the Philippines. The West Valley Fault, which goes across multiple densely populated locations, is predicted to cause it.
The Philippine government and disaster management agencies have been preparing for the likelihood of the Big One by holding regular earthquake drills, revising building codes and infrastructure standards, and implementing early warning systems. The goal is to decrease the possible impact of the earthquake, as well as the loss of life and property damage.
While the exact timing and intensity of the Big One cannot be anticipated with precision, it is critical for individuals and communities in earthquake-prone areas to be aware of the hazards and to take precautions to prepare for and respond to an earthquake. This involves keeping an emergency kit on hand, locating secure hiding places, and adhering to established evacuation procedures.
Preparing for an earthquake
Preparing for an earthquake in the Philippines can help minimize a seismic event’s risks and potential impacts.
Know the risks
Familiarize yourself with the earthquake hazards in your area. Learn about the local faults and the expected intensity of ground shaking.
Create an emergency kit
Prepare an emergency kit with food, water, first aid supplies, and a battery-powered radio.
Identify safe places
Identify safe places in your home or workplace to take cover during an earthquake. Avoid windows, mirrors, and other objects that can break or fall.
Secure your property
Secure heavy furniture and other objects that can tip over or fall during an earthquake. Check for loose fittings, electrical wiring, and gas connections.
Learn evacuation procedures
Familiarize yourself with the evacuation procedures in your area. Know the routes to the nearest evacuation centers and have a plan for reuniting with your family.
Participate in earthquake drills
Participate in earthquake drills organized by your local government or community. Practice drop, cover, and hold-on procedures, and learn how to respond in the event of an earthquake.
Stay informed about earthquake hazards and potential risks in your area. Monitor local news and weather reports, and be prepared to take action if necessary.
Government policies and programs
The Philippine government has implemented various policies and programs to prepare for earthquakes and minimize their impact on lives and properties.
National Disaster Risk Reduction and Management Plan (NDRRMP)
The NDRRMP is a comprehensive plan that outlines the government’s policies and programs for disaster risk reduction and management, including earthquake preparedness.
Philippine Institute of Volcanology and Seismology (PHIVOLCS)
PHIVOLCS is the government agency responsible for monitoring earthquake activity in the Philippines. It provides earthquake information and warnings, conducts research and assessment, and disseminates information to the public.
Earthquake drills and simulations
The government regularly conducts earthquake drills and simulations to raise awareness and prepare communities for seismic events. Schools, government offices, and private companies must conduct regular drills to ensure preparedness.
Building codes and standards
The government has established building codes and standards to ensure that buildings and structures are designed and constructed to withstand earthquakes. The National Building Code of the Philippines and the Philippine Earthquake Resilience and Safety Act are examples of these codes and standards.
Disaster response and management
The government has established disaster response and management systems to ensure a coordinated and effective response to earthquake emergencies. The National Disaster Risk Reduction and Management Council (NDRRMC) is the primary agency responsible for disaster response and management.
Community-based disaster risk reduction and management
The government promotes community-based disaster risk reduction and management (CBDRM) to empower communities to prepare for and respond to earthquakes. CBDRM involves capacity building, risk assessment, and the development of community-based disaster management plans.
The Philippines has experienced devastating earthquakes, and experts warn that a major earthquake, known as “The Big One,” is imminent. In light of this, there is a growing sense of urgency for disaster preparedness in the Philippines.
Disaster preparedness involves taking steps to prepare for potential disasters, including earthquakes. This includes creating emergency plans, stockpiling supplies, and educating oneself and others on how to respond in an earthquake. Individuals, families, and communities need to take an active role in disaster preparedness to minimize the impact of earthquakes on lives and properties.
The call to action for disaster preparedness in the Philippines is urgent and ongoing. The government, non-governmental organizations, and the private sector work together to promote disaster preparedness and resilience. However, it is ultimately up to individuals and communities to take responsibility for their safety and well-being. By taking proactive measures to prepare for earthquakes, the people of the Philippines can improve their chances of surviving and recovering from seismic events.