5.2 magnitude quake rocks parts of Mindanao

MANILA, Philippines – A 5.2 magnitude tectonic earthquake rocked parts of Mindanao before dawn yesterday but caused no damage and casualties, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.

Phivolcs director Renato Solidum said the quake occurred at 1:32 a.m. and was centered 23 kilometers southwest of Isulan, Sultan Kudarat, where it was felt at Intensity 4.

The tremor was also felt at Intensity 4 in Banga, South Cotabato; Intensity 3 in Palimbang, Sultan Kudarat; and Intensity 2 in the cities of Cotabato and General Santos.

Magnitude refers to the measure of energy of an earthquake specified on the Richter scale.

On the other hand, the intensity of an earthquake is a measure of the severity of shaking and its attendant damage at a point on the surface of the Earth.

Parts of Luzon, including Metro Manila, have experienced an “earthquake swarm” or series of tremors the past days caused by the movement of the East Luzon Trough off the northeastern seaboard.

Solidum said earthquake swarms were common and could last for over a month.

The Philippines sits on the Pacific “Ring of Fire,” where colliding plates in the earth’s crust cause frequent earthquakes and volcanic activity.

Solidum said about 20 quakes hit the country everyday but only a few are felt.            – Helen Flores