Be prepared for ‘Big One’

Experts yesterday warned of the possibility of a Magnitude 6 or 7 earthquake hitting Cebu province, albeit its arrival cannot be predicted.

“No one will know when this (strong earthquake) will happen. It may be tomorrow, it may be next month or the next years… so we should hasten our efforts,” said Baltazar Tribunalo Jr., head of the Provincial Disaster Risk Reduction and Management Office (PDRRMO).

Engr. Robinson Jorgio, officer-in-charge of PHIVOLS Lapu-Lapu Station, advised the public to be more open to realities, especially in a country vulnerable to natural hazards like earthquakes.

He said people should not be afraid of research findings but should be grateful that they are supplied with valuable information based on scientific study. He said awareness would enable everyone to prepare for any eventuality.

Tribunalo and Jorgio were among those present at the consultative meeting organized by the Philippine Institute of Volcanology and Seismology (PHIVOLCS) in Cebu City yesterday.

PHIVOLCS convened disaster managers, engineers, local officials, and other stakeholders to present initial results of their ongoing sciencebased research called the “Probabilistic Seismic Hazard Assessment of Metro Cebu.”

The ongoing study identified the Central Cebu Fault System, which is comprised of four active fault lines lying within the metropolis, as the most probable source of the earthquake.

In the north, the fault lines identified are the Daanbantayan lineament, which lies within the town, and the Bogo Fault, which transects Bogo City and San Remigio town.

But the main Cebu fault system is divided into two: The Central Cebu Fault and the South Cebu Fault.

The Central Cebu Fault transects Danao City, Compostela, Cebu City, Talisay City, Minglanilla, Naga City, Balamban, and Toledo City.

The South Cebu Fault transects Carcar City, Sibonga, Argao, Moalboal, Badian, Alegria, Dalaguete, Alcoy, and Boljoon.

An earthquake results from a sudden release of energy from the Earth's lithosphere that creates seismic waves or, as felt by humans, the shaking of the Earth's surface.

The last time Cebu experienced a massive quake was when a 7.2 magnitude earthquake hit Bohol in 2013.

Engr. Henremagne Peñarubia, science research specialist of PHIVOLCS, said that because there have been no strong earthquakes in Cebu province for the past five centuries, more energy has been stored, which can trigger a strong quake once the faults move.

“Lowlands in Metro Cebu, including the coastal areas, have higher risks of damage because this area is full of structures and buildings,” Peñarubia said.

Because higher risk is seen in metropolitan areas where concrete, high rise buildings abound, authorities are advised to take proactive steps.

Peñarubia said no one dies from an earthquake but casualties may result from hazards like buildings collapsing as the ground shakes.

During the meeting, the experts recommended proper engineering measures that will guide local authorities in designing, constructing or retrofitting buildings or establishment.

This means they should be built according to required standards outlined by the National Structural Code of the Philippines.

Peñarubia said buildings will not collapse easily if they are structurally sound. On the other hand, non-engineered or sub-standard structures may experience severe damage or collapse.

He said existing standards that do not comply with standards must be rebuilt, retrofitted, or disallowed in high risk areas.