Officials warn against building on fault lines

DAVAO CITY (MindaNews/7 October)—An official of the City Disaster Risk Reduction and Management Office (CDRRMO) said the city is mulling on implementing a strict ‘no build zone’ in areas that directly sit on the Central Davao Fault System.

The statement of CDRRMO head Alfredo Baloran echoes the sentiments of Office of the Civil Defense-Davao (OCD-11) Director Ednar Dayanghirang who urged local government units to prohibit the building of structures near identified fault lines in the region.

Workers rush out of their buildings after a quake hit Davao City Tuesday morning (29 October 2019). The magnitude 6.6 earthquake emanating from Tulunan in North Cotabato was felt as Intensity VI in Davao City. MindaNews photo by MANMAN DEJETO

Both officials made the statements following a “Walk the Fault” activity Monday, October 6 in which some 75 percent of the fault lines were marked by personnel of the CDRRMO, Philippine Institute of Volcanology and Seismology (PHIVOLCS), and the OCD-11.

The group marked the area between the Mintal Barangay Hall and the Mintal Gymnasium which sits on a segment of the Dacudao Fault, one of the active faults under the Central Davao Fault System.

Baloran urged home and building owners who built their structures prior to the mapping of the fault lines to check for structural integrity. He said while construction is still not prohibited on or within the five-meter buffer zone on each side of identified fault lines, buildings need to be assessed by structural engineers for safety reasons.

”If people observe anything unusual such as cracks in their houses or buildings, this means there is movement,” Baloran said in the vernacular.

But Baloran said they have yet to issue demolition orders saying the assessment of the structures will be done upon the completion of fault mapping activities which, he said, is now 75% complete.

Baloran said all structures within the five-meter buffer zone need to be able to withstand a magnitude 8 earthquake.

Kathleen Papiona , senior science research specialist and a geologist of the Department of Science and Technology (DOST) also explained that buildings near a fault line should undergo assessment of registered structural engineers as a magnitude 6 earthquake can already cause cracks.

”If we follow the building code, structures shouldn’t collapse at intensity 8. They might develop cracks at intensity 6 but they shouldn’t collapse,” Papiona said.

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) had earlier warned that Metro Davao is traversed by the Central Davao Fault System composed of Tamugan Fault, Lacson Fault, Dacudao Fault, Pangyan-Biao Escuela Fault and New Carmen Fault, which may produce earthquakes greater than magnitude 6.5. (Daniel Jamito/MindaNews)