By Ellalyn De Vera Ruiz and Keith Bacongco
A moderately strong magnitude-5.3 aftershock shook parts of Lanao del Sur and Bukidnon early Thursday, inflicting further damage on structures earlier affected by the magnitude-6.0 earthquake that hit the province a day earlier.
The aftershock struck eight kilometers northwest of Wao town at 4:01 a.m. yesterday.
As of 3 a.m. Thursday, 127 aftershocks have already been recorded and 33 have been located or plotted, said Janila de Ocampo of the Philippine Institute of Volcanology and Seismology (Phivolcs). Three of these, including the strongest aftershock measuring magnitude-5.3, were felt.
The 5.3 aftershock caused the ceiling of the female ward of Wao District Hospital to collapse and fall directly on some of the hospital beds. But no casualty was reported as patients were earlier evacuated following the 6.0 quake.
Disaster officials likewise reported that walls and ceilings of the Panang National High School, which were earlier damaged by the 6.0 quake that struck Wednesday, collapsed and fell on several computers. They said that the school, which has about 200 students, may not be ready when classes resume in June.
Other structures were also damaged, but disaster and local officials have yet to receive the formal reports.
Yesterday’s aftershock was felt at Intensity 6 or “very strong” tremor in Kalilangan, Bukidnon; Intensity 5 (strong) in Wao, Lanao del Sur; and Valencia City in Bukidnon; Intensity 4 in Kadingilan, Maramag, and Pangantucan in Bukidnon; Intensity 3 in Cagayan de Oro City; and Intensity 2 in Cotabato City and Koronadal City in South Cotabato, and Kidapawan City, Phivolcs said.
The magnitude-5.3 quake was an aftershock of the strong magnitude-6.0 tremor that occurred last Wednesday. The initial tremor was located 13 kilometers northwest of Wao, Lanao del Sur.
Phivolcs said the earthquake was of tectonic origin, which is caused by ground shaking primarily due to the sudden movement in the earth’s plates.
Phivolcs said the earthquake was generated by the movement of a northwest trending active fault in Lanao del Sur.
Officials said at least 170 structures were damaged by the magnitude-6.0 quake that hit Lanao del Sur last Wednesday.
In Kalilangan, Bukidnon, which was affected by the quake, the local legislative building was heavily damaged.
Mayor Omaradji Pizarro said the legislative building, built two years ago, may no longer be used given the damage. He said they might replace the walls and then check the beams and posts.
In Barangay Macaopao, a section of the national highway was also damaged but remains passable to motorists.
In the neighboring town of Wao, a three-story pension house was partially damaged, prompting the owner to cover the walls and windows with tarpaulins to contain falling debris during aftershocks.
In Barangay Serran, also in Wao, some residents have started putting up tents and sleeping mats on the school grounds.
Jenny Salvador said they are afraid that aftershocks would further damage their house and may cause injuries. She took her three-month-old son inside a camping tent at the school ground.
The earthquake in Lanao del Sur occurred a week after a magnitude-5.5 tremor was recorded in Batangas. A stronger magnitude-6.0 earthquake, which also originated in Batangas, was felt last April 8.
De Ocampo said the magnitude-6.0 quake in Batangas triggered at least 1,555 aftershocks as of 12 a.m. Wednesday. About 197 aftershocks were plotted or located and 17 were actually felt. (With reports from Mike U. Crismundo and Ali G. Macabalang)