Saturday, March 19, 2011

Tremors strike Mindanao; fear of "supermoon" spreads

ZAMBOANGA CITY, Philippines (Mindanao Examiner / Mar. 19, 2011) – A moderate earthquake struck the southern Philippines on Saturday, but there were no reports of injuries or damage to structures.

The U.S. Geological Survey said the 4.6 magnitude quake was traced about 68.9 kilometers off Davao and General Santos cities in Mindanao. It was the second earthquake that hit Mindanao within 24 hours after a 3.3 magnitude earthquake was reported in Cagayan de Oro city and some parts of Misamis Oriental province.

Filipinos, many of them who believe in superstitions and incredible tales of doomsday scenarios, are wary of earthquakes after a deadly tremor hit Japan last week and triggered a tsunami that devastated many areas and left a trail of death and destruction in one of the world’s richest countries.

The fear of tremors and tsunamis is made worse by gossips and false reports of rising sea water, volcanic eruptions and earthquake the “supermoon” would bring on Saturday. "We should get ready because of the supermoon. There will be earthquakes and tsunami because of the extreme gravitational pull of the supermoon," said Jeng Fernandez, who was told by a friend about the "supermoon" effect on Saturday night.

“Supermoon” is a situation when the moon is slightly closer to Earth in its orbit than on average, and this effect is most noticeable when it occurs at the same time as a full moon. So, the moon may seem bigger although the difference in its distance from Earth is only a few percent at such times.

The full moon occurs less than one hour away from perigee - a near-perfect coincidence that happens only 18 years or so, according to Geoff Chester, of the US Naval Observatory in Washington D.C.

Full moons vary in size because of the oval shape of the moon's orbit. It is an ellipse with one side (perigee) about 50,000 km closer to Earth than the other (apogee): diagram. Nearby perigee moons are about 14% bigger and 30% brighter than lesser moons that occur on the apogee side of the moon's orbit.
A full moon of rare size will rise in the east at sunset. It's a super "perigee moon" -the biggest in almost 20 years. A perigee full Moon brings with it extra-high "perigean tides," but this is nothing to worry about, according to National Oceanic and Atmospheric Administration.

In most places, lunar gravity at perigee pulls tide waters only a few centimeters higher than usual. But contrary to some reports circulating the Internet, perigee moons do not trigger natural disasters. The "super moon" of March 1983, for instance, passed without incident. And an almost-super moon in December 2008 also proved harmless, the National Aeronautics and Space Administration also said. (Mindanao Examiner)

No comments: