Volcanic mountains

Tonga’s underwater volcanic eruption triggered nearly 590,000 lightning strikes

The massive underwater volcano off Tonga last month not only sent record-breaking ash plumes into the air, but also led to one of the largest volcanic flashes ever seen.

According to GLD360, the global ground-based lightning detection network owned and operated by Vaisala, the eruption triggered nearly 590,000 lightning strikes which were “unprecedented”.

The lightning nearly engulfed the surrounding islands of the Tonga archipelago, according to Vaisala meteorologist Chis Vagasky.

“I can’t imagine what the people of the islands would have been through, with a massive ash cloud overhead, a tsunami flooding everything they own, and cloud-to-ground lightning falling around them,” did he declare.

“It must have felt apocalyptic.”

Lightning nearly engulfed the surrounding islands of the Tonga archipelago, according to Vaisala meteorologist Chis Vagasky

Ash from Tonga eruption seen from SPACE

Ash sent into the air by the huge underwater volcanic eruption in Tonga has been photographed by astronauts from the International Space Station.

NASA has shared the remarkable images taken from the windows of the ISS cupola, showing a blanket of ash from plumes spewing thousands of feet into the atmosphere.

The event was so striking that satellites captured the moment of the eruption, with ISS astronauts snapping images of plumes and ash blankets above the region.

Read more: Ash from volcanic eruption in Tonga seen from SPACE

Based on the data, Reuters created an incredible animation showing the increase in lightning strikes from January 13 to January 15.

On January 13, an explosion above the surface caused a major flash, which lasted until January 14.

Then, on January 15, the massive eruption of the Hunga Tonga-Hunga Ha’apai submarine volcano triggered a wave of nearly 400,000 strikes in just six hours.

In total, there were nearly 590,000 lightning strikes over the three days, far more than the second largest event, the Anak Krakatau eruption in Indonesia in 2018.

“During the Anak Krakatau eruption in December 2018, we detected around 340,000 events over a week-long period, so detecting almost 400,000 in just a few hours is extraordinary,” Vagasky said.

According to GLD360 data, around 56% of lightning around Tonga struck the land or ocean surface – including 1,300 strikes that hit the main island of Tongatapu.

The remaining 44% of lightning strikes likely traveled within the ash plume or between clouds.

“The percentage of lightning categorized as cloud-to-ground was higher than what you would normally see in a typical thunderstorm, and higher than what you typically see in volcanic eruptions, which creates some interesting research questions,” said said Vagasky.

A volcanic eruption causes two main types of lightning: dry charge and ice charge.

On January 13, an explosion above the surface caused a major flash, which lasted until January 14.

Then, on January 15, the massive eruption of the Hunga Tonga-Hunga Ha'apai submarine volcano triggered a wave of nearly 400,000 strikes in just six hours.

Based on the data, Reuters created an incredible animation showing the increase in lightning strikes from January 13 to January 15.

Although caused by different materials in the atmosphere, volcanic lightning and that of a typical thunderstorm are both the result of particle charging.  When there are large accumulations of positive and negative charges in the atmosphere, electrons flow between them, which is called lightning

Although caused by different materials in the atmosphere, volcanic lightning and that of a typical thunderstorm are both the result of particle charging. When there are large accumulations of positive and negative charges in the atmosphere, electrons flow between them, which is called lightning

Dry load occurs when a volcano’s plume is “small” (up to 2.5 miles high) and fractured ash, rocks, and lava particles rub against each other, accumulating enough charge to cause a lightning strike.

During this time, ice loading occurs with large plumes (up to 7.5 miles in height), which reach the area where water can freeze.

In the case of volcanic eruptions, this water tends to come from magma, whereas with standard lightning, it comes from clouds.

According to Vagasky, both forms of lightning occurred during the Tonga eruption – the dry charge on January 13 and the ice charge on January 15.

The presence of seawater around the eruption also likely played a role in the thunderstorm.

The massive underwater volcano off Tonga last month not only sent record-breaking ash plumes into the air, but also led to one of the largest volcanic flashes ever seen.

The massive underwater volcano off Tonga last month not only sent record-breaking ash plumes into the air, but also led to one of the largest volcanic flashes ever seen.

It triggered a 7.4 magnitude earthquake, sending tsunami waves crashing across the island, leaving it covered in ash and cut off from outside help.

It triggered a 7.4 magnitude earthquake, sending tsunami waves crashing across the island, leaving it covered in ash and cut off from outside help.

When lava comes into contact with water, it breaks up into smaller pieces, increasing the number of particles available for collision.

However, several questions remain about why volcanic lightning occurs, particularly at the level of the interaction of microscopic particles.

“Scientists are already working to understand what made the Hunga Tonga eruption so violent, from the size of the explosion, to the shock wave and pressure wave that traveled around the world, to the tsunami and the amount of lightning,” Vagasky concluded. .

“A lot of research will be done in the months and years to come to figure it out.”

The eruption itself was one of the strongest on record, according to a recent study.

Its explosive yield was rated at between 5 and 30 million tons of TNT equivalent by NASA scientists who studied preliminary data from the January 15 explosion.

The eruption of Mount St Helens in Washington State in 1980 produced the same yield as about 24 million tons of explosive TNT.

Hunga Tonga-Hunga Ha’apai, an undersea volcano in the South Pacific, spewed debris up to 25 miles into the atmosphere when it erupted nearly a fortnight ago.

This 7.4 magnitude earthquake sent tsunami waves crashing on the coasts causing destruction and leading to the death of three people in the area.

Why does lightning strike?

Lightning occurs when strong updrafts generate static electricity in large, dense thunderclouds.

Some parts of the cloud become positively charged and others negatively charged.

When this charge separation is large enough, a violent electrical discharge occurs, also called lightning.

Such a discharge begins with a small area of ​​ionized air hot enough to conduct electricity.

This small area turns into a forked lightning channel that can reach several kilometers in length.

The channel has a negative tip which dissipates charges to the ground and a positive tip which collects charges from the cloud.

These charges move from the positive end of the channel to the other negative end during a flash, causing the charge to be released.