After sleeping for over 40 years, the Philippines' Taal volcano awoke over the weekend, blasting a plume of ash at least 32,000 feet into the sky.
And in this ominous plume, thunder clapped and lightning streaked through the dark column of volcanic ash.
The profoundly dangerous Taal — with over 24 million people living within 60 miles of the volcano — produced a scintillating, at times mesmerizing, light show. (Taal's activity also prompted a mass evacuation of almost 1 million people should there be a bigger eruption.)
Volcanic lightning, however captivating, is common, explained Sonja Behnke, a scientist at Los Alamos National Laboratory who researches these volcanic phenomena and has repeatedly observed volcanic lightning in places like Iceland and Japan.
— shuajo (@joshibob_) January 12, 2020
If you're mesmerized by the steamy #Taal eruption plume and wondering why it's creating so much #VolcanicLightning, you’re not alone. Here’s a micro-crash course on the physics of volcanic thunderstorms for non-specialists. Thanks to @joshibob_ for the incredible footage! (1/14) pic.twitter.com/CCl6zw56RZ— Alexa Van Eaton (@volcaniclastic) January 13, 2020
How volcanic lightning happens
There are two major steps.
1. First, the volcanic ash needs an electric charge. When a volcano erupts explosively (as opposed to gentler lava eruptions from, for example, Hawaiian volcanoes), it ejects exploded particles of molten rock (aka "magma") into the air, which becomes volcanic ash. In the towering plume of ash, these billions of particles start colliding and rubbing against each other, which creates charged volcanic particles. It's similar to how you create static electricity by rubbing socks on carpet. "The ash gets charged as the volcano is erupting," said Behnke.
"It’s essentially the same reason we get lightning and thunder in storm clouds," added atmospheric scientist Adam Varble, who researches thunderstorms at Pacific Northwest National Laboratory. "It's the collision of particles." But in storm clouds, instead of ash particles rubbing together, it's only ice particles colliding together to create electric charges.
2. Then, to get bolts of lightning, the charged particles need to separate into different regions of a volcano's ash plume. In the chaotic plume, this happens naturally as differently sized ash particles fall down at different speeds, creating different zones of charged particles, either positive or negative. (What gives one region of particles a positive or negative charge is "complicated physics" that's still being investigated, explained Varble.)
But the important point is when you have two regions of oppositely charged particles, the space between becomes an electric field, which allows electricity to shoot or flow through the air. These are the bolts of lightning you see streaking through storm clouds or volcanic plumes.
Dramatic video shows bolts of lightning as a volcano spews ash up to nine miles into the air in the Philippines.
The country has raised the alert level, meaning an "explosive eruption" could happen in the coming hours or days: https://t.co/28tNsT07uQ pic.twitter.com/VV04MoFDQR— CNN (@CNN) January 13, 2020
These radiant bolts of lightning, whether in volcanic plumes or thunderstorms, are powerful, creating between 10 million volts to billions of volts, explained Varble. (Toasters usually operate at between 120 to 220 volts.)
Taal certainly created lots of lightning. That's likely because the plume reached so high into the freezing atmosphere that water ejected during the eruption turned into little ice particles, which also started colliding and creating static electricity, explained Behnke. This means there was a double whammy of both ash and ice creating charged particles.
There may have been a lot of water in Taal's ashy plume, because a lake sat on top of the volcano, meaning the eruption blew through a lake.
"It seems like volcanoes that have a good interaction with water when erupting get more dramatic displays of lighting," said Behnke.
For volcano scientists, volcanic lightning is more than just a natural spectacle. The U.S. Geological Survey now uses lightning to track volcanic eruptions as they happen, said Behnke.
Many eruptions happen in remote places and aren't directly observed by people. But lightning is detectable from satellites, which gives scientists' better insight into the planet's constantly erupting volcanoes.
"It's very common during explosive ash-producing eruptions," Alexa Van Eaton, a USGS volcanologist, tweeted. "So common, in fact, that we use it to help monitor volcanism around the world."
What’s causing lightning during the Philippines eruption? Experts explain the phenomenon
Posted January 13, 2020 5:31 pm
WATCH: Video captures rare volcanic lightning sprawl upwards from Philippines volcanoAs the Taal volcano erupts near Manila, Philippines, blanketing the surrounding island of Luzon in thick plumes of ash and sending streaks of lightning into the sky, volcanic experts break down the science behind the phenomenon.
Not all volcanoes emit lightning when they erupt, but the spectacle, they say, is hardly rare.
Volcanic lighting is “actually pretty common,” particularly with eruptions
that produce a lot of ash, said Melanie Kelman, a volcanologist at Natural Resources Canada.
WATCH: Video captures rare volcanic lightning sprawl upwards from Philippines volcanoAs the Taal volcano erupts near Manila, Philippines, blanketing the surrounding island of Luzon in thick plumes of ash and sending streaks of lightning into the sky, volcanic experts break down the science behind the phenomenon.Not all volcanoes emit lightning when they erupt, but the spectacle, they say, is hardly rare.
Volcanic lighting is “actually pretty common,” particularly with eruptions
that produce a lot of ash, said Melanie Kelman, a volcanologist at Natural Resources Canada.
According to Kelman, the phenomenon begins when water interacts with magma in an explosive fragmentation of hot rock under Lake Taal
The rocks, which erupt as a result of the explosion, break into even smaller particles known as volcanic ash.
“The finer the ash, the more likely you are to get lightning, she said. “When an explosive volcanic eruption produces an ash column, collisions between ash particles (which may be thousandths of a millimetres in size) produce friction, which generates electrical charge.”
A turbulent column of volcanic ash rises, creating a plume full of charged particles that eventually plummets, covering the ground in ash. Particles crash into one another, illuminating the skies with hazardous lightning.
Volcanic lightning is a lot like a thunderstorm
“You have to imagine that obviously there are millions of billions of particles which are ejected in these clouds, that carry some charges with them,” said another volcanologist, Corrado Cimarelli.
He said electrical charges dispatched through static electricity are the essence of volcanic lightning.
Cimarelli, who teaches physical and experimental volcanology at Germany’s Ludwig Maximilian University of Munich, told Global News the process, called “tribal electrification,” is similar to the way lightning forms during thunderstorms.
“The reason why they actually charge is because they collide against each other,” said Cimarelli.
“If you have a series of particles which are grouped together and they have a specific polarity — a positive or negative, and they are distant enough to basically break the electrical insulation of the air in between — then you will have a discharge happening.”
According to Cimarelli, these charged particles are then lofted up into the atmosphere at high altitudes — about six or 10 kilometres in in the case of the Taal volcano — where they then freeze and circulate inside the plume.
The ice that forms is “actually the carrier of charges into the thunderstorms,” he said.
But the explosiveness of the eruption, the size of the ash, the presence of ice particles, and the water content and temperature of the volcanic plume all play roles in the number and size of lightning discharges.
Lightning flashes as Taal Volcano erupts on Jan. 12, 2020, in Tagaytay, Cavite province, outside Manila, Philippines. Bogie Calupitan / The Associated Press
“There is some evidence that eruptions with more water produce less lightning — this may be because wet eruptions tend to be more explosive, and more explosive eruptions may scatter ash particles over a larger area, resulting in fewer ash particle collisions,” said Kelman.
The temperature of the environment wouldn’t matter, but the amount of water available has the potential to create larger explosions.
“If a volcano is near or in the ocean, if there is a lake in a volcanic crater, if there is a lot of groundwater, if there is a lot of water dissolved in the magma, or if there are glaciers on a volcano that can be melted to produce water, then an eruption may be more explosive than it would have been otherwise,” she said.
“More water tends to lead to greater explosivity, resulting in finer ash.”
Not your typical campfire ash
Since the volcano’s eruption, Filipino authorities have begun evacuating thousands of people near the capital of Manila, going so far as to urge a full evacuation.
The Department of Science and Technology at the Philippine Institute of Volcanology and Seismology raised the alert status to Level Four and urged a total evacuation of Taal Volcano Island within a 14-kilometre radius from the volcano’s main crater.
Civil aviation authorities were advised to avoid flying near the volcano due to “airborne ash and ballistic fragments from the eruption column.”
The warning echoed the 2010 eruption of the Eyjafjallajökull volcano in southern Iceland, which saw 800 people evacuated from the region and the closure of European air spaces for several days thereafter.
Kelman said ash is more volatile than it appears, and is actually shattered volcanic rock.
“It’s not like ash from a campfire, which is soft and organic and it dissolves. Volcanic ash is like sand. So tiny particles of it are a hazard to aircraft … because they can sandblastst any surface, including the windshield or the control surfaces,” said Kelman.
“The ash particles can go into any part of the airplane or like instruments for navigation and whatnot. And then really critical is that the ash can go into the engine and melt and then be re-deposited on the the turbine blades. So it can cause jet engines to stall.”
Taal: Time-lapse of lightning storm swirling round Philippine volcano
Time-lapse footage has captured a lightning storm swirling in dark clouds around the peak of the Taal volcano in the Philippines.
The volcano had spewed a giant plume of ash, prompting thousands of people to be evacuated.
Officials said the plume from the Taal volcano stretched 1km (0.6 miles) into the sky.
- 12 Jan 2020
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