‘FOREWARNED IS FOREARMED’ DOST: Earthquake scenarios meant to inform, not to scare

By Rjay Zuriaga Castor

Earthquake and tsunami scenarios being presented for Western Visayas by authorities are not predictions but scientific projections meant to guide preparedness and reduce risk, a top official of the Department of Science and Technology (DOST) said.

DOST Secretary Renato U. Solidum Jr. said earthquake scenarios are developed to show what could happen — not what will happen — based on geological data, fault activity, and previous events.

“These are not predictions but scenarios. A prediction is you tell the time, when exactly, the magnitude, and what will happen. This is an earthquake scenario. Scenarios are prepared so that people are made aware of the possibilities,” he said on Tuesday.

He stressed that these scenarios are not made out of fiction but are “science-informed scenarios” used to help communities and local governments plan their disaster response systems.

Solidum said the public should not panic over advisories from authorities or even reports from the media, but use them as guides for preparation.

“This should not be taken as information that you should fear, but information that you should consider to prepare. Why? Because if you don’t have those scenarios, you will be caught unaware, and you are not ready. So, don’t be afraid,” he emphasized.

MAJOR QUAKE GENERATORS

Solidum said the Negros Trench and the West Panay Fault are the two major earthquake generators that could trigger powerful ground shaking and even a tsunami in Western Visayas.

He stressed that the two geological features represent the worst-case earthquake scenarios that local governments and communities must prepare for in their disaster risk reduction plans.

Solidum said the Negros Trench, located west of the Negros Island Region, has already moved in the past and generated a tsunami reaching up to two meters high in Southern Negros and Iloilo City.

“A one- to two-meter tsunami wave is dangerous to human life. Even a half-meter tsunami is dangerous,” he added.

Meanwhile, the West Panay Fault, which runs across parts of Panay Island, poses a threat of strong ground shaking, ground rupture, landslides if it slips, or even fire incidents.

Solidum said residents near the fault line must observe a five-meter buffer zone on both sides to avoid ground rupture hazards.

He also pointed out that with these two scenarios—on-land earthquake and offshore earthquake—the public has to prepare for different outcomes.

“Our preparedness would be somewhat different. Coastal towns should prepare for a tsunami, and those further away from the coast can look for normal earthquake hazards,” he said.

He noted that most towns in Panay are not directly above the fault line, but local governments should still prepare for Intensity VIII shaking, similar to what was experienced during the 1948 Lady Caycay earthquake, one of the strongest recorded in the region.

“We advise governments to prepare for an Intensity VIII shaking or when you cannot stand anymore,” he said.

Solidum stressed that earthquake preparedness should focus on enforcing the National Building Code and ensuring that homes and infrastructure are built according to engineering standards.

He said buildings that are very old or have been weakened, or constructed without the benefit of approval or supervision of a civil engineer, are most likely to be severely affected by an earthquake.

“If the buildings have followed the building code, even at Intensity VIII, the house or building is not expected to collapse. But how do you follow the code? The design, the materials should be standard, and the workmanship should be very good,” he added.