CATAINGAN, Masbate--- A possible landslide may occur in Cataingan town due to ground ruptures with or without rainfall as aftershocks continue to hit the island province of Masbate, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
Paul Alanis, Phivolcs Bicol chief, said that as of 7:00 PM on Saturday (Aug. 29) evening, at least 488 aftershocks were recorded within the Cataingan fault line after the main quake.
Alanis said that they will be checking for liquefaction, land ruptures, sea sinkhole and ground subsidence in Masbate as soon as the Inter-Agency Task Force (IATF) allows them.
“We will be looking into this in the coming days for more detailed study. We already received the initial report from the residents,” he said.
He said that they have to follow IATF protocols for people coming from outside the province.
As to residents whose houses were under water after the earthquake, Alanis said that it happened due to ground subsidence. Subsidence is the sinking of the ground due to underground material movement. It occurs due to caving in of natural underground voids or hole.
When asked why the two hectares land area in the mountains broke into pieces after the 6.6 earthquake magnitude, Alanis said that it was due to ground ruptures.
“Rupture can occur in flat ground, hilly terrain or under the sea. But I would wait for mappers to visit it first. We will wait for mappers to see the bigger view," he said.
Ground rupture occurs when an earthquake rupture along a fault affects the earth surface.
Alanis said the Mines and Geosciences Bureau (MGB) will study the sinkholes, while Phivolcs will check out on earthquakes and associated hazards.
He said the decrease in water sources is possible due to ground rupture resulting in water sources to go down.
Earlier, Rep. Olga Kho of (2nd District, Masbate) told Ako Bicol partylist Reps. Elizaldy S. Co and Alfredo Garbin during the solons visit in Masbate over the weekend that ground ruptures took place uphill of Salvacion Village in Cataingan town.
The two hectares upland area planted with coconut trees collapsed through a massive landslide totally covering with soil 20-feet tall coco trees.
Kho also said that several water sources in Cataingan town totally dried up shortly after the 6.6 magnitude earthquake.
The Office of Civil Defense in Bicol reported more than P300 million damages to public and private infrastructures as a result of the Aug. 18 quake.