The Office of Civil Defense (OCD) directed its regional offices in Ilocos (Region 1), Cagayan Valley (Region 2), and Central Luzon (Region 3) to create a comprehensive tsunami evacuation plan in light of the movement of the Manila Trench that triggered an earthquake swarm.
The OCD said Saturday, Dec. 28, that it was closely monitoring areas that are likely to be impacted by a tsunami, a series of sea waves commonly generated by under-the-sea earthquakes, following the recent series of quakes that jolted off the coast of Santa Catalina, Ilocos Sur last week.
OCD Administrator, Undersecretary Ariel Nepomuceno issued a memorandum order directing civil defense offices in Regions 1, 2, and 3 “to undertake essential actions for tsunami preparedness, including drafting a comprehensive tsunami evacuation plan.”
“The NDRRMC [National Disaster Risk Reduction and Management Council] emphasized that evacuation routes must be clearly mapped out to ensure accessibility, prioritizing communities that require a swift 15-minute response time,” the OCD said.
Meanwhile, the Provincial Disaster Risk Reduction and Management Offices (PDRRMOs) in Region 1 were placed on a heightened alert amid a tsunami threat.
To help them craft an appropriate response plan, the OCD discussed historical data related to destructive tsunami events in the country with Department of National Defense (DND) Sec. Gilberto Teodoro Jr., who also serves as the chairperson of the NDRRMC.
“This analysis will help establish a framework for countermeasures aimed at mitigating damages when hazards exceed anticipated levels. In line with this, the identification of worst-case scenarios has been emphasized, allowing for comprehensive planning,” the OCD noted.
On Friday, Dec. 27, OCD deputy administrator for operations Director Cesar Idio convened an urgent tsunami preparedness meeting in Camp Aguinaldo, Quezon City to address the potential impacts of a tsunami following seismic activity off Ilocos Sur’s shores.
It can be noted that 50 earthquakes were recorded between Dec. 17 to 20 with magnitudes ranging from 1.8 to 5.0 due to the movement of the Manila Trench, which experts said could trigger an even bigger rumbling with a magnitude of 8.4.
The Manila Trench is an oceanic trench located west of the Philippines which has a depth of about 5,400 meters.
During the meeting, the OCD said it was “actively researching tsunami events and countermeasures to save lives.”
“Insights from Japan's early warning system, recognized as one of the most effective in the world, are being studied to enhance the Philippines' preparedness for tsunami events,” the civil defense agency pointed out.
According to the Philippine Institute of Volcanology and Seismology (Phivolcs), there have been instances of tsunami incidents in the country.
On Aug. 17, 1976, the Phivolcs said that a magnitude 8.1 earthquake in Moro Gulf produced up to nine-meter-high tsunamis which devastated the southwest coast of Mindanao and left more than 3,000 people dead, with at least 1,000 people missing.
Meanwhile on Nov. 15, 1994, a magnitude 7.1 earthquake in Mindoro also generated tsunamis that left 49 casualties.
The Phivolcs said that the cities of Valenzuela, Navotas, Malabon, Manila, Pasay, Las Piñas, and Parañaque “face the threat of tsunami that could be generated from a possible movement of the Manila Trench,” prompting the need for local government units (LGUs) to be prepared for any eventuality.