‘GET READY, CEBU’: Phivolcs says ‘disaster imagination’ is key to preparation

The response to earthquakes and typhoons should not be fear, but better preparation.

“We should be able to ask ‘What if’ and then plan from there,” said Renato Solidum, director of the Philippine Institute of Volcanology and Seismology in an interview.

However, he said the usual process of disaster risk management of local governments stops at identifying hazards in an area and assessing the magnitude of a natural calamity.

“What I recommend is getting a total picture through ‘disaster imagination’,” he said.

This process, he said, requires having detailed data to do a “risk assessment” of losses to lives, the economy, structures and other aspects in order to come up with scientific “scenarios” of the impact and damage that could happen.

After the 2012 earthquake in Negros Oriental and the 7.2-magnitude earthquake in Bohol province in 2013, he said Cebu province should take a closer look at how prepared it would be to withstand a powerful tremor.

Solidum was one of the speakers in a two-day roadshow “Iba na ang Panahon: Science for Safer Communities” of the Department of Science and Technology that opened yesterday in Cebu City.

He said computer software developed by Phivolcs is available for free to local governments to give specific scenarios of how a city, town or province would be affected by different intensities of earthquakes.

To use it, Phivolcs has to train personnel, ideally the disaster risk reduction managers and land use planner of a locality.

He showed slides of “what if” scenarios of earthquakes with epicenters in Cebu, Bohol, and the Negros Trench.

Intensities are shown in colors on maps of the different island.

For example, a magnitude 7.5 earthquake in Cebu, which has at least four known geological fault lines, would show the island awash in the color red reflecting intensity 7 to 8 or “very destructive” impact “in most areas of Cebu, Bais and Dumaguete.”

An intensity 7 or “destructive” impact would affect the northern tip of Cebu, northern half and western areas of Bohol and many areas of Negros”.

Magnitude is the measurement of the energy of an earthquake while intensity reflects the impact or damage on an area, which would depend on the population and density of buildings there.

“Region 7 has been affected in the past by earthquakes, tsunamis and volcanic eruptions. It can be affected again by these geological hazards in the future,” said Solidum.

While no one can predict when an earthquake will strike, he said “We have the tools for preparing scenarios for earthquakes, tsunamis and volcanic eruptions.”

With this, he said a locality can plan a full response to any given disaster, by knowing exactly how many lives would be endangered or buildings ruined, and then come up with a recovery plan that is based on reality.

The Rapid Earthquake Danger Assessment System (REDAS) has been used in Metro Manila, Sorsogon, Albay and Cavite and is being shared with local governments, academic partners and national agencies.

The database is so flexible, he said, it can integrate existing maps and data about population, geography and the number, location and description of buildings so that any damage scenario can be generated, whether it is a typhoon or even fire.

Solidum noted that “nobody in Central Visayas has asked me yet to speak about this tool or how to do an earthquake assessment here… maybe that’s because before 2012, there were no major geological events.”

However, the earthquakesin Bohol and Negros Oriental that were felt in Cebu, with strong aftershocks, have shattered the illusion that Cebu is “earthquake-free”.

The last recorded powerful earthquake in Cebu island was in Jan. 28, 1922, where it registered intensity 7 and 8.

The shocks damaged old structures in Cebu City and Mactan, including the Recoletos Church and convent. Cracks in the soil were noticed in limestone banks on the Mactan seashore. Camotes island also suffered a shock of greater intensity, Solidum reported.