The orange radiance above the crater of Kanlaon Volcano visible in photos taken at 3 a.m. to 5 a.m. Sunday, Feb. 2, was a superheated plume and not crater glow, a Philippine Institute of Volcanology and Seismology official said.
“It’s a superheated plume, its heated volcanic gas being emitted along with ash,” Ma. Antonia V. Bornas, Phivolcs Volcano Monitoring and Eruption Prediction Division chief, told DIGICAST NEGROS.
The orange light or incandescence can only be seen through sensitive camera lenses and not through the naked eye, she said.
Nature photographer John Kimwell Laluma, who posted the volcano photos on his Facebook page that went viral on Sunday, said his intent was to capture the Milky Way’s galactic core as it rises over Mount Kanlaon.
“After a few initial exposures, I was surprised to see an orange glow emanating from the crater. I immediately switched to a telephoto lens to capture it and get a closer look,” he said.
It was not visible to the naked eye, and was only observable through a long exposure shot hence the presence of star trails in the photograph, he said.
Photos of Kanlaon Volcano taken by John Kimwell Laluma*
Phivolcs has been monitoring superheated plumes since November that is why Alert Level 3 was raised at Kanlaon, Bornas said.
“We already have signs of magma coming out as ash,” she said.
The ash emission started in October and at the start the magma content was low but it has since been increasing, she said.
“Cameras have infra-red capabilities. So they can see heat with the right setting…The glow on those photos are an artefact of camera technology”, Bornas said.
What was photographed Sunday was not crater glow or “banaag” that can be seen with the naked eye, and does not disappear because the magma is practically at the crater and about to flow out as lava.
“Crater glow is an indication that we will have a lava flow or lava fountaining event. It’s like what happened in Mayon Volcano,” she said.
This is also what happened in the 1754 eruption of Taal Volcano which started with a strombolian or the lava fountain activity that they saw reflected on the surface of Taal Volcano Island, she added.
Lava and its hot volcanic gas heat the air above the volcano and make the crater glow, Bornas said.
The superheated plume that was captured comes and goes with the degassing or ash emission, Bornas said.
Degassing happens when there is fracturing within the volcano, she said.*