By Jorge Hallare
LEGAZPI CITY --- An aerial survey over Mount Mayon was conducted Friday morning last week by a group of scientists from the Philippine Institute of Volcanology and Seismology (Phivolcs), Earth Observatory of Singapore, and some civil defense officials to gather steam emission directly from the volcano’s summit and record its volcanic activity in “real time.”
Eduardo Laguerta, resident volcanologist of Phivolcs-Legazpi, said the group that included five chemists led by Dr. Regan Rebadoria collected steam emissions near the summit for “real time monitoring” of the situation inside the volcano.
He said they will compare the real-time data with the recorded data gathered through the so-called remote monitoring that uses Phivolcs’ instruments installed at its observatory stations in Barangay Masarawag in the town of Guinobatan and in Malilipot town, both in Albay.
According to Laguerta, they sometimes find difficulty gathering sulfur dioxide or SO2 emissions because of unfavorable weather condition that tends to provide inaccurate data.
“This is why we gather plumes from the summit itself (when the weather is fine),” he said.
Laguerta added the volume of gas gathered from the volcano is very important for a “complete” record of the observed parameters of Mayon’s activity.
He said another reason for the real-time monitoring is to get a picture of what’s inside the lava dome when viewed from the summit.
Laguerta said they need to get data on the volume of materials that remained inside since the volcano’s 2014 phreatic (or steam-driven) explosions.
“The power inside the volcano is ascertained by the depth of magma underneath which also causes the swelling or inflation of the mountain,” he said.
He added that the data they had gathered during their “precise leveling” at Mount Mayon in January showed a “slight inflation” that was added to the “inflation recorded” during the explosion of Mayon years ago.
“Even if physically Mayon is quiet we do not really know what is happening underneath her,” said Laguerta.
He said the present study and observations are significant as they are wary of the ensuing danger should there be a sudden phreatic explosion, especially now that it is summer.
Laguerta said the slightest explosion of ash puffs is already extremely dangerous, especially at the volcano’s rim.
He explained that even if the surface of the lava dome is hardened there is steaming liquid underneath that could pose a lot of danger when sudden phreatic explosions occur.
Laguerta said when this happens “the 45-degree slope of the mountain could trigger an avalanche of pyroclastic materials,” referring to the cloud of ash and lava fragments carried through air and vapor during volcanic eruptions.
He said geologists from Phivolcs-Manila again plan to conduct a “precise leveling” around Mayon volcano on the first week of the second quarter to get the latest data of the inflation of Mayon.
Laguerta said they would compare it with the result of the SO2 emissions gathered during the aerial survey conducted Friday last week.
He added that whatever result they would get they will present it to the Albay Public Safety and Emergency Management Office, which is in charge of disaster risk reduction and mitigation efforts in the province, and to members of the media.