The Philippine Institute of Volcanology and Seismology (PHIVOLCS) is the government agency that deals with tectonic and volcanic activities in the Philippines. One of the major concerns of this government agency is the monitoring of earthquakes that affects the country.

The Philippines is located at the rim of the Pacific Ring of Fire and the country experiences mild earthquakes every day because of this. With the many earthquakes that rock the country every day, how does PHIVOLCS determine if the earthquake is destructive or not? The answer to that is the PEIS.

PEIS stands for PHIVOLCS Earthquake Intensity Scale. It measures how the earthquake is felt in an area. The PEIS is felt on the relative effect of the earthquake to people, structures, objects and surroundings. The scale starts from Intensity I, which is the weakest, to Intensity X, which is the strongest.

Here is the scale as established by PHIVOLCS on PEIS:

Intensity I: Scarcely Perceptible.

Intensity II: Slightly Felt

Intensity III: Weak

Intensity IV: Moderately Strong

Intensity V: Strong

Intensity VI: Very Strong

Intensity VII: Destructive

Intensity VIII: Very Destructive

Intensity IX: Devastating

Intensity X: Completely Devastating

Those are the complete list for the PEIS. For description of each intensity scale of the PEIS, please visit the PHIVOLCS website.