PHIVOLCS sees 'minor' aftershocks from magnitude 5.9 Occidental Mindoro earthquake

Only light or minor aftershocks may be expected following the magnitude 5.9 earthquake that jolted Lubang, Occidental Mindoro on Tuesday, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) said Wednesday. 

Interviewed on Unang Balita, PHIVOLCS director Teresito Bacolcol said the aftershocks may range from magnitude 4 to 4.9.

“Dito sa [Occidental] Mindoro, we won’t consider ‘yung aftershocks as strong aftershocks. ‘Yung [magnitude] 5.9 ‘yung main shock and 5.9 is considered as a moderate earthquake,” he explained. 

(We won’t consider the aftershocks in Occidental Mindoro as strong aftershocks. The magnitude 5.9 was the main shock and that is considered as a moderate earthquake.)

“Usually, ‘yung aftershocks would be one degree lower than the main shock. Most likely around 4.9 ‘yung magiging aftershock natin na maximum (would be the maximum aftershock). [Magnitude] 4 to 4.9 would be considered as light earthquakes or minor earthquakes,” he added. 

The magnitude 5.9 quake struck at 4:23 p.m. on Tuesday, was tectonic in origin, and had a 60-kilometer depth of focus. It was also felt in parts of Metro Manila. 

Bacolcol said Tuesday's earthquake was not connected to the recent tremors, particularly the powerful magnitude 7.4 earthquake that hit Hinatuan, Surigao del Sur on Saturday. 

“Walang koneksyon ang mga lindol na naranasan natin in the past few days. ‘Yung generator sa Surigao is the Philippine Trench, and ang generator naman kahapon is the Manila Trench. Hindi ‘yan sila magkakaugnay at wala pong koneksyon ‘yung lindol kahapon at sa Surigao,” he said. 

(The earthquakes that we’ve experienced in the past few days were not connected. The generator in Surigao was the Philippine Trench, and the generator yesterday was the Manila Trench. Yesterday's earthquake and that one in Surigao were not related and there was no connection between them.) 

According to the PHIVOLCS director, there are six active trenches and 175 active faults in the Philippines, so there is always a possibility that their movements would be simultaneous or consecutive. 

He also stressed the importance of following the “duck, cover, and hold” method during an earthquake, and watching out for natural signs of tsunamis after. 

“Kapag may strong shaking and halos hindi ka na makatayo, and there is a sudden retreat of seawater, and there is a rumbling sound coming sa dagat, then kahit ano man dito sa tatlo, kapag na-perceive niyo na, you have to move out and evacuate to a higher place kasi baka magkaron ng tsunami,” Bacolcol said. 

(When there is a strong earthquake and you could hardly stand, and there is a sudden retreat of seawater, and there is a rumbling sound coming from the sea, then you have to move out and evacuate to a higher place because there might be a tsunami.) —KBK, GMA Integrated News