Earthquakes: Lurking Danger
Public safety and security start with mitigation and preparedness, and the Philippines has to specifically prepare for earthquakes given its precarious location within the Pacific Ring of Fire. This region encircling the Pacific Ocean is a plate boundary, whose constant movements cause frequent earthquakes and volcanic eruptions.
Records from the Philippine Institute of Volcanology and Seismology (Phivolcs) of the Department of Science and Technology (DoST) show that the Philippines lives through an estimated 100–150 earthquakes every year.
Many of these earthquakes are largely unnoticeable. Others, though, can be catastrophically strong, leaving a trail of death and devastation in their wake.
Take for example the two earthquakes that rocked Surigao del Sur one after the other on 2 and 4 December 2023 — one a magnitude 7.4 and the other a magnitude 6.8. Over 130,000 families were evacuated, with infrastructure damage estimated at P4.8 million, including 3,887 damaged houses.
A year earlier, a magnitude 7.0 earthquake shook Tayum, Abra, killing 11 people, injuring 615, and displacing thousands. It also left an estimated ₱1.88 billion in infrastructure damage as houses, buildings, roads and other structures were either completely destroyed or damaged.
More of these damaging quakes occurred in years past, and more of them will happen in the years ahead. This inevitability, no matter how grim, underscores the need to be prepared and calls to mind President Marcos’ plea “to establish a culture of preparedness.”
But as no one can ever predict when an earthquake will occur, a good start in fulfilling PBBM’s preparedness ethos is to improve the safety and durability of the country’s buildings and other infrastructure.
This is precisely why the DoST-Phivolcs developed the Seismic Hazard Atlas for the Design Earthquake (SHADE) of the Philippines, which the agency officially launched on 21 November 2024 at the Phivolcs Auditorium in Quezon City.
A Vision for the Future: Stronger, More Durable Infrastructure
SHADE is an atlas that shows the Maximum Considered Earthquake (MCE) considering a 2475-year period for the Philippines. The maps included in SHADE reflect the Phivolcs-generated high-quality seismic hazard ground motion maps meant to serve as critical guides for structural design and urban planning in earthquake-prone areas, like localities near and around faults.
Created with the full support of DoST in partnership with the Association of Structural Engineers of the Philippines (ASEP), SHADE is being implemented by DoST-Phivolcs and monitored by the DoST-Philippine Council of Industry, Energy, and Emerging Technology Research and Development (PCIEERD).
It specifically aims to improve the safety and durability of buildings across the country by providing the scientific foundation for earthquake-resistant design practices.
This carefully curated atlas seeks to enhance the capacity of Filipino engineers and architects to design structures that are better equipped to handle seismic events and, in the process, play a leading role in safeguarding not only properties, but also lives.
Through SHADE, DoST-Phivolcs also aims to raise awareness in proper construction and building practices and improve earthquake preparedness to ultimately strengthen the Philippines’ resilience to natural hazards and support sustainable community development across the country.
“My message is, the Philippines is a seismically active country with different hazards… For seismic, we have this map now that can be used for seismic design,” noted Dr. Rhommel N. Grutas, Supervising Science Research Specialist at Phivolcs.
SHADE provides the necessary ground motion seismic hazard through the MCE maps to provide the engineers, building authorities and other stakeholders critical information to comply with international seismic design standards.
SHADE also features the Transition Long Period Map of the Philippines; a map that can help engineers assess the impact of long-period ground movement so they can design structures that can withstand prolonged and repeating seismic activity.
According to Dr. Grutas, SHADE is “intensive” as it contains all relevant data pertaining to faults and the geologies of the different localities in the country. It also details seismicity in the Philippines dating back to 1654 — giving users of this atlas the complete picture of any and all locations.
“So, we did the disaggregation, if there are gaps, the faults. We studied each fault, what are the magnitudes that always come back in the past several years, or what else can happen in a fault that has had a strong earthquake,” Dr. Grutas pointed out.
“That’s why our coverage is a 2,500-year return period. So, that’s the design. Just like in the US, with that 2,500-year return period, we can get strong earthquakes, not just moderate and small earthquakes. So, we did a very intensive study.”
The project, Dr. Grutas said, ostensibly began in 2022, when the agency’s budget for it was first approved. However, actual project development started only in March 2023 with a two-year timeline for completion.
Despite the abbreviated timeframe, DoST-Phivolcs got the job done, officially launching SHADE on 21 November 2024 at the Phivolcs Auditorium.
“This atlas is a crucial resource for improving the safety and durability of buildings across the country, providing the scientific foundation for earthquake-resistant design practices,” said DoST-Phivolcs during the launch of SHADE.
Why SHADE Matters
Historical data is empirical and bodes well for preparedness.
Hence, it is safe to infer that strong earthquakes will rock the Philippines — anywhere and at any time, sparing nothing and no one.
As scientists race around the clock to unravel the many mysteries of earthquakes, the best thing Filipinos can do at present is heed the President’s impassioned plea for everyone “to follow proactive, vigilant, and adaptable strategies for our own and our communities’ safety.”
Engineers, builders, relevant government agencies, and local government units can do their part by leveraging SHADE to ensure the viability, integrity, and durability of every structure — houses, buildings, roads, and other infrastructures —throughout the country.
“If you’re a designer, the building should not collapse for the people to have time to evacuate. That is the primary purpose of our design. The building should not collapse because many people may get injured or die,” Grutas emphasized. “If our structures are like that, I think, we can be resilient. We have to mitigate that risk.”
For his part, DoST Secretary Renato Solidum Jr., described the comprehensive atlas as “a significant milestone” during his speech at the launch of SHADE.
“When we want to prepare the Philippines for its various natural hazards, we need to make sure that the location of our structures is in a less hazardous place, or for us to be able to make it resilient,” Secretary Solidum said.
“In summary, we are providing the engineering and science data for a more appropriate building design. The successful development of the Seismic Hazard Atlas for Design Earthquakes in the Philippines marks a significant milestone in our ongoing efforts to enhance disaster risk mitigation across the nation, making us at par or the same level as other advanced countries,” the DoST Secretary concluded.
To make sure every relevant stakeholder can follow PBBM’s directive, DoST-Phivolcs provides a copy of the Seismic Hazard Atlas for the Design Earthquake (SHADE) available upon request on the Phivolcs website — for free. The atlas can be downloaded in PDF format for easy reference.
Ultimately, SHADE is meant to help the Philippines prepare for the long term. With its carefully curated maps, engineers, architects and similar stakeholders now have a comprehensive guide on how to best build structures in an earthquake-prone country.
This aligns perfectly with PBBM’s calls for enhanced, forward-thinking, and science-based disaster preparedness and will save Filipino lives when The Big One — knock on wood — strikes the Philippines.
