UP NIGS head says unexpected volume of rain caused Itogon landslide

The director of the UP-National Institute of Geological Sciences (UP-NIGS) on Tuesday said unexpected volume of rain from Typhoon Ompong may have triggered the deadly landslide at Barangay Ucab, Itogon, Benguet.

Interviewed on Unang Balita, UP-NIGS director Dr. Mario Aurelio said the landslide that added to Itogon's high death toll may have resulted from the rain accumulating at areas that have never received high amounts of rainfall before.

"Nung unang panahon, hindi doon talaga ang pinakamabigat ang ulan. Pero ngayon ang nangyari, dun napunta sa Barangay Ucab," he said.

The rain aggravated the state of the land at the mining site, which was previously declared as a landslide-prone area.

Aurelio explained that landslide-prone areas have steep sides and weak or rotting soil.

"Naghihintay na lang 'yung bundok na 'yun para bumagsak, ang kailangan na lang 'yung trigger," he said, noting that rain and earthquakes were big triggers for landslides.

Typhoon Ompong offloading one month's worth of rain around the area may be the main culprit in the landslide, but Aurelio concurred that small-scale mining may have contributed to the ground's instability.

"Malamang, puwede rin, lalo na ito na small-scale mining na hindi regulated. Walang design, walang plano pagminina nila. Ang tendency ng small-scale miners, hukay lang ng hukay," Aurelio said.

When the Benguet Mining Corporation abandoned the mine in the 90's, Aurelio noted that local small-scale miners were allowed to make their livelihoods in spite of the dangers the area posed.

"Ang problema, hindi na nga regulated," he said.

The Mines and Geosciences Bureau (MGB) of the Department of Environment and Natural Resources (DENR) carried out an awareness campaign and study of landslide-prone areas following the Cherry Hills landslide in 1999.

Itogon and other landslide-prone areas around the country were surveyed and placed in hazard maps. —Rie Takumi/KBK, GMA News