The Philippine Online Chronicles

While yesterday's New Zealand shaker happened at the same time as a slight tremor in the Philippines, the earthquakes aren't related and Filipinos have nothing to worry about.

Six mild tectonic earthquakes were recorded yesterday by the Philippine Institute of Volcanology and Seismology (Phivolcs), more than in other days in February. Another occured at 2:30 a.m. this morning.

According to Phivolcs Science Research Specialist Wenchelle Sevilla, the Philippines is in no immediate danger from strong quakes such as yesterday's 6.3-magnitude New Zealand shaker, because the two countries are far from each other.

"The structures where the Philippines and New Zealand lie are far from each other. They are on separate plates, so while tremors were felt in Manila, the earthquakes are not related," he said.

The Philippines, which is bisected by several fault lines, lies on the Eurasian and Philippine plates. The recent earthquakes in New Zealand, according to scientists there, were "caused by the ongoing collision between the Pacific and Australian tectonic plates."

Yesterday's 4.7-magnitude quake was felt at Intensity IV in Manila and Dasmarinas; Intensity III at Quezon City, Pasay City and Pasig; Intensity II in Occidental Mindoro; and Intensity I in Pampanga.

"The Philippines frequently experiences mild earthquakes. So far we have not recorded any abnormal activity, even at the Marikina fault," Sevilla said.

The Marikina fault line, which is closest to Metro Manila, was said by Phivolcs director Renator Solidum Jr. in 2009 to have locked, and while it is not moving, is classified as active because it has moved before.

While yesterday's tectonic activity was notable because it was felt by people around the Metro, the recent quakes were too mild to cause much structural damage, despite a report of a cracked glass panel in a restroom in the Quezon City Hall compound.

However, Sevilla emphasized that Filipinos are always advised to be prepared for emergencies, and building engineers should always be wary of earthquakes. The country is part of the Pacific Ring of Fire, an area vulnerable to natural disasters such as earthquakes and volcanic eruptions, thus the government encourages implementing safety precautions.

Recent earthquakes near the Philippines, Australia and New Zealand
Image from the US Geological Survey, Feb 23, 2010. (Click to enlarge)

No eruptions

Strong earthquakes may trigger volcanic activity, but people can rest easy as eruptions are not foreseen to occur due merely to the recent tremors.

Mt. Bulusan's recent ash fall, for example, was a "preatic explosion," meaning it was caused by the contact of groundwater with the volcano's magma source.

The volcano is still just at Alert Level 1, Phivolcs noted in its 7:00 a.m. bulletin, and while the source of activity is hydrothermal and shallow, entry to the four-kilometer Permanent Danger Zone is still prohibited due to the risk of sudden steam and ash explosions.

No volcanic activity has been reported at Mayon Volcano, and no eruptions are imminent at Taal Volcano.

The Department of Foreign Affairs (DFA) reported that two Filipinos are trapped in a collapsed building in New Zealand, said ABS-CBNnews.com.

The two Filipinos' condition is still being verified by the DFA, but initial reports said they are under the rubble of the Canterbury Television building in Christchurch.

A state of emergency has been declared in New Zealand because of yesterday's quake, which caused multiple casualties and injuries in the country's capital.

The latest death toll is at 75, but the search continues.