MGB finds 1,333 sinkholes in Bohol

CEBU CITY, Philippines—Experts have found 1,333 sinkholes in areas in Bohol province, which was hit by a 7.2-magnitude quake last year, following a study  concluded last week.

A team from the Mines and Geosciences Bureau (MGB), of the Department of Environment and Natural Resources (DENR), presented its findings and recommendations to Gov. Edgar Chatto in an exit conference held last week.

Liza Manzano, supervising science research specialist of the MGB, reported to the governor that out of the 1,333 sinkholes, 198 had been previously identified in a map that shows sinkhole locations.

The study covered 14 areas in Bohol, including the city of Tagbilaran, that were hardest hit by the quake.

It covered the towns of Loon, Maribojoc, Sagbayan, Antequera, Cortes, Tubigon, Loay, Calape, Clarin, Danao, Carmen, Catigbian, San Isidro and Balilihan.

The MGB team recommended the continued monitoring of the sinkholes for up to a year to give geologists more time to observe and study changes brought by aftershocks and rain.

Loreto Alburo, regional director of the MGB, told the Inquirer that before the MGB team met with the governor for an exit conference, there had been an agreement with Chatto for another round of  study covering 17 municipalities that were tagged by the Department of Social Welfare and Development (DSWD) as hardest hit by the quake in terms of human suffering and displacement.

The DSWD, according to Alburo, has made 42,771 requests for studies covering areas that are being considered as residential sites for people displaced by the quake.

Three teams of geologists will be sent this week to Bohol to conduct the study together with another team from the MGB central office, Alburo said.

The MGB teams are also completing a map that will show areas prone to landslides, floods and subsidence in 20 municipalities in the province.

The MGB teams had conducted a total of 120 tests that experts call ground-penetrating radar (GPR) runs for the report that was presented to Chatto during the exit conference.

The report recommended the demolition of buildings that suffered quake damage, including those that are on the former site of Natalio P. Castillo Sr. Memorial Hospital in Loon.

According to Manzano, the structures were adding pressure to unstable slopes and the subsiding ground of the former hospital site.

Last month, President Aquino visited one of the hospital’s retrofitted buildings.

The building temporarily accommodates patients and has a 25-bed capacity.

The new site for the hospital, however, is to be constructed at the vacant lot below the former hospital site.

Patients were formerly admitted in makeshift hospital tents.

The MGB team also recommended the declaration of five new GeoPark (geological) sites—Maribojoc-Loon Uplifted Reef Flats, Catigbian Karst Window, Sagbayan Spalling Hills and Sinkholes, Danao Gorge and Dagohoy Hill, and Inabanga Rupture Zone.

These sites, according to the MGB, showed unique geological features.

The Chocolate Hills in Bohol has already been declared as a geological monument.

Chatto said that with this development, officials could now have additional attractions for Bohol for its planned “GeoScience” tour.