EXPLAINER: What do people feel in Intensity VII earthquakes?

In the morning of June 8, a magnitude 7.8 earthquake hit Maasin, Sarangani, which left destructive effects on the affected areas.

The earthquake has different effects on different areas depending on how near or far they are to the epicenter. The highest felt was Intensity VII in General Santos.

In an interview with Balitanghali, PHIVOLCS Director Dr. Teresito Bacolcol described the effects and scenarios of an intensity VII.

“Magnitude 7.8, that is already considered a major event,” Bacolcol said.

“Kapag intensity VII ‘yan 'yung pinakamataas na reported intensity natin, that is already considered as destructive,” he added.

(When it reaches intensity seven, which is the highest intensity we've reported, that is already considered destructive.)

According to PHIVOLCS, magnitude is the energy released by an earthquake at the focus. It is calculated from earthquakes recorded by an instrument called aseismograph.

On the other hand, intensity is the strength of an earthquake perceived and felt by people in a certain locality. Intensity is generally higher near the epicenter.

The following are the possible impacts of an intensity VII earthquake, according to PHIVOLCS:

• People will be frightened
• People on the upper floors would find it difficult to stand
• Heavy objects and furniture will overturn or topple
• Big bells in churches will ring
• Old and poorly built structures will experience considerable damage
• Even well-built structures may be slightly damaged
• Cracks on walls, dikes, fish ponds, road surface, or concrete hollow blocks may occur

According to Bacolcol, with an earthquake of this intensity, the affected areas could experience aftershocks as high as magnitude 6.8.

PHIVOLCS reminds the public that the “duck, cover, and hold” protocol is only effective for protecting against falling debris and not from building collapse.

Entering buildings that sustained cracks during the earthquake is not recommended, according to PHIVOLCS. —AOL, GMA News