Active Faults and Disaster Risk Management in the Philippines

ACTIVE FAULTS IN THE PHILIPPINES

Overview of Active Faults in the Philippines

  • The Philippines has nearly 30 active faults, leading to increased risk for communities facing earthquakes.
  • The geographical positioning of the country is along the Philippine Mobile Belt, which is characterized by intense tectonic activity.
  • Factors contributing to this phenomenon include the convergence and compression of three primary tectonic plates:
    • Sunda Plate
    • Philippine Sea Plate
    • Eurasian Plate

The Philippine Fault System

  • Philippine Fault System (PFS): Comprised primarily of the Philippine Fault Zone (PFZ).
  • Location: The PFZ is situated roughly 1,200 km behind the Philippine Trench, in proximity to multiple subduction zones.
  • Movement: The fault exhibits a slow movement rate within the range of 2.0extto2.5extcm/year2.0 ext{ to } 2.5 ext{ cm/year}.

Notable Active Faults

  • List of Active Faults:
    • Guinayangan Fault
    • Masbate Fault
    • Leyte Fault
    • Sibuyan Sea Fault
    • Bangui Fault
    • Digdig Fault
    • Infanta Fault
    • Eastern Mindanao Fault
    • Central Leyte Fault
    • Lianga Fault
    • Mati Fault

Areas Traversed by the Philippine Fault Zone (PFZ)

  • The PFZ impacts a variety of regions across the country including:
    • Ilocos Region
    • Nueva Ecija
    • Quezon Province
    • Masbate
    • Caraga
    • Davao Gulf
    • Leyte
    • Davao Oriental

Special Fault Systems

Marikina Valley Fault System (MVFS)
  • Location: Extends from Biñan to Taguig, traversing through central Metro Manila.
  • Hazard Assessment: The MVFS poses significant risks, including:
    • Risk to lives
    • Injuries
    • Destruction of properties
  • Identified as one of the most dangerous and active fault systems in the Philippines.
Areas Covered by MVFS
  • Regions Affected:
    • Biñan
    • Calamba
    • Carmona
    • Marikina
    • Rodriguez (Montalban)
    • Muntinlupa
    • Oriental Mindoro
    • Pasig
    • San Mateo (Rizal)
    • San Pedro (Laguna)
    • Santa Rosa (Laguna)
    • Tagaytay
    • Taguig
Western Philippine Fault Line
  • This fault diverges from typical land faults, being situated in Philippine maritime areas.
  • Region Traversed:
    • Luzon Sea
    • Mindoro Strait
    • Panay Gulf
    • Sulu Sea
  • Implications: The movement of this fault is a concern due to its proximity to densely populated cities, posing risks to residents especially in the Southern Mindanao region.
Southern Mindanao Fault Line
  • Characteristics: Features creeping, which is defined as a slow, continuous ground movement.
  • Classification: This fault is categorized as a strike-slip fault, where land moves horizontally side to side, similar to the movement seen in the Marikina Valley Fault System.
  • Provinces Affected:
    • Agusan del Norte
    • Agusan del Sur
    • Aurora
    • Davao del Norte
    • Eastern Leyte
    • Masbate
    • Quezon
    • Southern Leyte
    • Ilocos Norte

Emergency Management and Disaster Risk

Importance of Emergency Management
  • Emergencies arising from natural disasters (like earthquakes) often result in injuries and loss of life.
  • The presence of numerous active faults in the Philippines enhances the potential for earthquake hazards.
  • The risk escalates when communities are exposed and unprepared for such events.
  • Adequate emergency management strategies can significantly mitigate impacts and protect lives.
Disaster Risk Management (DRM)
  • Definition: According to the United Nations Office for Disaster Risk Reduction (UNDRR), DRM encompasses the application of knowledge to formulate plans and strategies that prevent disasters or minimize their impacts.
  • Key Features:
    • DRM enhances community resilience against risks.
    • It is integral to understanding and implementing the Emergency Management Cycle.
Types of Disaster Risk Management
  • Prospective DRM: Aims to prevent the emergence of new disaster risks.
  • Corrective DRM: Focuses on minimizing existing risks.
  • Compensatory DRM: Offers financial protection, such as insurance coverage.
  • Community-Based DRM (CBDRM): Engages families and local communities in the process of disaster planning and response.

Policies and Framework

Sendai Framework for Disaster Risk Reduction (2015–2030)
  • Guidelines suggest that plans, programs, and resources should be responsive to the levels of need identified.
  • Disaster risk reduction measures must be tailored to address the distinct requirements of individuals.
Community-Based Disaster Risk Management (CBDRM)
  • Local communities act as the initial line of defense against disasters.
  • Residents possess the best understanding of their local conditions, aiding in need identification and coordination for planning, preparation, and response efforts.
  • Government support is vital for equipping communities to enhance safety and resilience.

Emergency Management Cycle (EMC)

  • Purpose: Provides a systematic approach aimed at disaster risk reduction.
  • Goals: Aids individuals and communities to:
    • Prevent
    • Mitigate
    • Prepare
    • Respond
    • Recover
Phases of the Emergency Management Cycle (EMC)
  • The EMC consists of a structured four-phase strategy for disaster management:
    1. Prevention and Mitigation: Actions taken before disasters occur.
    2. Preparation: Establishing readiness procedures before disasters strike.
    3. Response: Implementation of measures during the occurrence of disasters.
    4. Rehabilitation and Recovery: Focused on resuming normalcy post-disaster.
  • Attention to planning must be meticulous and organized.
Prevention and Mitigation (First Phase)
  • Focus on actions taken prior to an earthquake, including:
    • Prevention: Involves enhancing structures to withstand disasters.
    • Mitigation: Involves strategies to minimize potential damage and losses.
  • Example: Schools located near the West Valley Fault face risks during strong earthquakes (e.g., the anticipated “Big One” in Metro Manila), which may lead to:
    • Collapse of bridges and roads
    • Structural damages
    • Injuries and casualties
Prevention and Mitigation in Schools
  • Schools should undertake several measures including inspections of the physical infrastructure, such as:
    • Walls
    • Water lines
    • Electrical connections
    • Doors and windows
    • Hanging lights and fixtures
    • Bolting cabinets to walls
    • Laminating glass
    • Securing lighting fixtures

Oplan Metro Yakal

  • Definition: A government contingency plan established for the anticipated impact of a magnitude 7.2 earthquake emerging from the Marikina Valley Fault System (MVFS).
  • Structure: Metro Manila has been divided into four quadrants to facilitate organized evacuation and response protocols.
  • In instances where Local Government Units (LGUs) are overwhelmed, support will be provided by other regions and Armed Forces of the Philippines (AFP) brigades.

Assisting Regions & AFP Units

  • North: Coordination with Regions I & VII; AFP Northern Luzon Command (NOLCOM)
  • East: Support provided from Regions II & XI; AFP Southern Luzon Command (SOLCOM)
  • West: Regions V & VI coordinated through AFP NOLCOM
  • South: Coordination with the Cordillera Administrative Region (CAR) & Region X; AFP SOLCOM

Tsunami Preparedness

  • Monitoring of earthquakes and tsunami threats is undertaken by the Philippine Institute of Volcanology and Seismology (PHIVOLCS).
  • Alerts are disseminated across various platforms including text, radio, TV, and social media.
Tsunami Alert Levels
  • Watch: Advise to be prepared and aware of evacuation routes.
  • Advisory: Recommendation to maintain distance from beaches and waterways.
  • Warning: Immediate evacuation to higher ground is required.
  • No Threat / Alert Lifted: No action required.

Rehabilitation and Recovery (Final Phase of EMC)

  • Focus on managing post-earthquake situations including:
    • Assessing damage based on extent and severity.
    • Aiming to restore normalcy to community life and livelihoods.
    • Necessitates ongoing and thorough execution of recovery plans.