A COASTAL survey in Glan, Sarangani Province, found that long stretches of shoreline, coral reef, and seagrass beds have been exposed, particularly in Pangyan Marine Sanctuary, Brgy. Pangyan, DENR XI reported on Sunday.
The Department of Environment and Natural Resources (DENR) XI said the coastal uplift was reported following the Magnitude 7.8 earthquake that struck Sarangani and General Santos City on June 8.
According to PHIVOLCS, coastal uplift refers to the vertical deformation of the coast in response to the upward and downward movement of the crust along a fault or subduction zone.
The aerial survey and ground validation on June 11, conducted by the PHIVOLCS and Mines and Geosciences Bureau XII, confirmed that a coastal uplift in Barangay Pangyan raised the seabed by two meters and extended the shoreline by 200 meters.
According to PHIVOLCS, the team also observed a co-seismic coastal uplift in barangays in Glan, Sarangani, and in the southern portion of Glan and Jose Abad Santos, Davao Occidental.
For example, corals previously submerged were found exposed on the surface, altering the shoreline as a direct result of the earthquake.
The Sarangani Bay Protected Seascape (SBPS) Protected Area Management Office (PAMO) initially received reports on June 10 from Glan residents that the sea levels remained low and had not returned to their normal state since the quake.
“These exposed corals and seagrass beds had begun dying off alongside their resident organisms such as reef fishes, eels, clams, and shells,” DENR said in a statement.
It added that residents raised concern that the stench of decaying marine life could poison them.
The SBPS PAMO mobilized rangers to document other incidents of coastal uplift or habitat damage in Sarangani Bay.
Meanwhile, a composite team with the MGB XII and partner LGUs with the DENR XII will be created to conduct a scientific study of the Glan coastal uplift on Tuesday, June 16.
Residents are advised to report other incidents of coastal uplift through the SBPS-PAMO Hotline Nos. 0909-618-9917 (Smart) or 0995-305-0306 (Globe).
The June 8 earthquake, which struck at 7:37 a.m. with its epicenter 32 kilometers west of Maasim, Sarangani, generated tsunami waves of up to one meter along the coasts of Kiamba, Maasim, and Kalamansig in Sultan Kudarat.
PHIVOLCS said it was felt as far as Leyte and recorded a peak intensity of PEIS VII in General Santos City.
Sarangani and its neighboring provinces have a documented history of strong seismic activity, with at least seven significant earthquakes with magnitudes between 5.7 and 8.0 rocking the area between 1917 and 2023.
The most recent earthquake before June 8 was a magnitude 6.8 quake on Nov. 17, 2023.
