Iloilo City – Geologists of the Mines and Geosciences Bureau Region-6 (MGB-6) recommended that the management of Tigbauan National High School should closely monitor if there are further ground movements in the school as it informed MGB-6 that it experienced one last year.
The school is located in the municipality of Tigbauan in southern Iloilo.
MGB-6 Regional Director Leo Van V. Juguan, CESO V, said that the recommendations were based on the results of the geohazard assessment conducted by four geologists from MGB-6 last April.
The principal of Tigbauan National High School, Ms. Juanita B. Braña, requested the MGB-6 to conduct an inspection of the said school because of a ground movement they experienced in September last year.
As reported by Ms. Braña, the school staff heard a sound as if a big hammer hit the concrete floor of the school’s administration building. Early this year, they observed that the floor tiles were separating downward from the wall. Big cracks on the wall can also be seen, she added.
This led the school management to write MGB-6 and request for a geohazard inspection. Acting on the school’s concerns, MGB-6 sent four geologists from MGB-6 to conduct the inspection last April 16, 2015.
During the site assessment, the team used two geophysical techniques which are Georesistivity Survey and Ground Penetrating Radar (GPR) Survey.
Mae Magarzo, OIC-Chief of the Geosciences Division of MGB6 said that “based on the geohazard assessment, one cause of ground movement in the area is differential settlement due to the underlying clay layer.”
“Differential or uneven settlement occurs when the soil beneath a structure cannot bear the weight imposed. And this can cause cracks in the structure’s foundation and interior walls as well as uneven settling of doors and windows,” MGB-6 geologists further states in their report.
It can be seen from the results of the geo-resistivity and GPR surveys that the ground on which the school administration building stands is made up of sandy and clayey materials and areas underlain by clayey materials are prone to differential settlement,” said Magarzo. She added that withdrawal of groundwater in the area may have also caused ground subsidence in the school.
RD Juguan said that the school authorities should constantly monitor the area for signs of continued movement and they must immediately report their observations to the proper authorities such as the Municipal Disaster Risk Reduction Management Council or MDRRMC.
Part of the recommendations of MGB-6 is for engineers to consider potential geologic hazards particularly ground movement which was already experienced, and the rock and soil types of the area in the design or modifications for the school’s future structures, Juguan said.
The MGB-6 team communicated their findings and recommendations to the school management and the municipal government of Tigbauan, Iloilo, he concluded. (LAA/MGB-6)