Mother Nature can turn from benevolent to destructive so quickly. On the afternoon of Monday, Luzon was rocked by an earthquake that measured 6.1 in magnitude. The brunt of the tremors was felt in the Central Luzon region, with an epicenter in Zambales and a greater portion of damage in Pampanga. No less than fifty aftershocks arrived following the main quake. But the country’s seismic troubles did not end there. The following Tuesday, another earthquake struck to the south. This time it was recorded in Eastern Visayas, and the magnitude of 6.5 was even stronger than the one in Luzon.
CNN Philippines reports that the Philippines received a double whammy of earthquakes in two of its major geographical divisions on April 22 and 23. The Monday quake in Luzon had its epicenter located at Castillejos, Zambales by the Philippine Institute of Volcanology and Seismology (PHIVOLCS). Initially registered at magnitude 5.7, it was upgraded to 6.1 as the extent of damage was calculated. And indeed, the province of Pampanga saw significant devastation following the tremors despite not being the epicenter. PHIVOLCS on Tuesday attributes this to most of the area sitting on soft sediment that is easily disturbed by seismic activities.
“The actual location of the epicenter is in the mountains in between the provinces of Pampanga and Zambales,” explains PHIVOLCS head Renato Solidum Jr. “Unfortunately, there are several towns in both provinces that are underlain by soft sediment.” Case in point, a four-story shopping center in Porac, Pampanga was collapsed by the quake last Monday. The soft sediments are mostly the result of the 1991 Mount Pinatubo eruption, which blanketed the area with lahar that was later rebuilt over by the various communities it covered. In Zambales, Subic and Olongapo were similarly affected, this time because of either closeness to the sea or being floodplain.
Sixteen people have been reported killed in the Monday quake. In addition, Clark International Airport was temporarily closed to all flights until Wednesday, to allow investigation of possible dangerous damage to its runways and facilities.
Complicating matters on taking stock after the Luzon quake is a follow-up tremor on April 23, this time in the Visayas. The epicenter this time was San Julian in Eastern Samar, with the 6.5 earthquake happening 1:37 PM. In the intricacies of seismology mechanics, Director Solidum notes that despite the higher magnitude the Visayas quake yesterday was not classified as “major.” Roadways and bridges showed damage following the shaking, and parts of Eastern Samar had lost power. PHIVOLCS also assured the public that this quake and the Luzon tremor were not related to one another.
As part of emergency procedures, institutes such as schools and public places like malls in Samar were evacuated during the tremors. Social media was also flooded with images of earthquake damages to landmarks like the Catbalogan City Hall and a San Julian Church, the crucifix of which had fallen down.
Images from ABS-CBN News, Inquirer