Monday, October 27, 2014

Mayon behavior very tricky -- lady volcanologist

LEGAZPI CITY, Oct. 26 (PNA) -- The current restiveness of Mount Mayon is considered by a lady scientist of the Philippine Institute of Volcanology and Seismology (Phivolcs) as the trickiest within a period of 50 years.

“It’s very tricky for us and anytime soon, the Mayon volcano could change because magma is there and pre-positioned already,” Ma. Antonia V. Bornas, chief of volcano monitoring and eruption prediction division, said on Sunday.

Bornas said their study showed that the magma beneath the volcano is not only ascending towards the conduit but also expanding in the volcano’s base called magma dike, causing the surface inflation to accommodate bigger volume of magma buildup.

So, the volcanologist said, they cannot bring down the alert level status of Mayon from level 3 to level 2 because the magma is there already and anytime soon, it will explode.

“So we need to make our best judgment as scientists just like what sir Ed Laguerta said,” Bornas explained.

In 2001, the lava dome showed up for five months before an explosion took place. But before the explosion took place, Bornas said, an oozing lava trickled down the slopes of the volcano; subsequently a big bang followed where a deadly pyroclastic flow as hot as 1,200 degrees Celsius rolled down.

“While in the sky, a 10 to 12-kilometer high cauliflower-type ash clouds rocketed and blanketed the province in broad daylight, causing apprehension among the residents living near the foot of Mayon,” she added.

Laguerta, Phivolcs senior resident volcanologist in Bicol, earlier on Saturday said it was very dangerous to interpret on a day-to-day basis the behavior of Mayon as the pressure within the volcano may go sky-high, with the magma being on the verge of the crater rim.

“Once the magma’s static pressure becomes stronger than the tihostastic pressure—meaning, magmatic pressure should overcome the lithostatic pressure or the confining pressure -- this will lead to explosion,” Laguerta said.

Unlike the typhoon or pregnant woman whose due date or landfall is easily predicted, the volcano eruption is like an earthquake that could not be determined as it may happen even without precursor, claimed the veteran volcanologist who has spent most of his time and career monitoring Mayon’s daily activities.

With this, Laguerta reiterated to the public to stay away from the six to 8-km extended danger zone to prevent untoward incident should Mayon explode.

He also asked the public to listen only to the authorities as to the advisory regarding the restive situation of Mayon as even without alert level the volcano could erupt without warning.

Laguerta’s timely warnings on the activities of Mayon have saved the lives of thousands of Albayanos in the past eruptions of Mayon.

A few impatient individuals, however, have questioned the scientifically-based warnings of the Phivolcs official who has explained that whatever bulletin comes out daily from the agency its the cumulative report of the heads and representatives of the various departments and units composed of experienced and expert scientists.(PNA) CTB/FGS/RBB/CBD/PJN