image source,NOAA
Tonga’s massive volcanic eruption and tsunami on Saturday (Jan 15) caused catastrophic damage, destroying homes and blanketing many communities in a thick layer of ash.
Tsunami waves from volcanic eruptions hit Australia, New Zealand, Japan and the west coast of the Americas, and atmospheric shock waves were detected around the world.
The Tongan government described the eruption as an “unprecedented disaster”. The gas, dust and debris from the volcanic eruption rushed to an altitude of 20 kilometers.
Communication with Tonga has been severely disrupted even after four days have passed. The main reason is that the only undersea cable connecting the country to the outside world broke during a volcanic eruption.
So far, three people have been reported dead in the disaster, including a woman from the UK.
The BBC explains the devastation and impact of the disaster with satellite imagery and illustrations.
Where is Tonga?
Tonga is located about 3,300 kilometers east of Australia and consists of about 170 islands, many of which are uninhabited.
The erupting volcano, Hunga Tonga-Hunga Ha’apai, is located more than 60 kilometers north of the capital Nuku’alofa.
On Saturday, the center of the volcano sank, disappearing into the ocean floor.
About two hours later, it erupted with incredible power.
After the eruption, almost all volcanic formations and the surrounding land disappeared.
The eruption triggered a huge atmospheric shock wave that traveled at about 300 meters per second.
After 15 hours, pressure changes were also detected on the other side of the world in Europe.
The blast was heard across the Pacific from Fiji to Alaska.
How fast can a tsunami spread?
The tsunami waves produced by the tsunami quickly swept across the Pacific Ocean.
They arrived in New Zealand in 5 hours and Alaska in about 10 hours.
Experts say the tsunami may have been caused by the collapse of debris on the seafloor, propelled by pressure waves on the sea surface.
The tsunami wave continued into Sunday, and it was still recorded in Australia on Monday (January 17).
It’s worth noting that tsunami waves can be much more damaging than normal ocean waves, even if they’re not particularly high.
Ordinary waves can take 15 seconds to reach the shore and then back up.
Some tsunami waves in Australia were less than 1 metre but lasted nearly 30 minutes.
They continued to move ashore for 15 minutes and took about 15 minutes to return.
Why are volcanic eruptions so violent?
Experts are still evaluating the exact reason for the violent eruption.
Some believe that the speed at which the lava erupted from the volcano may have played a big role.
When magma laden with volcanic gas is forced through seawater at high speed, there is no time for a layer of steam to cool it.
This “fuel-coolant interaction” could lead to a massive chemical explosion, the researchers said.
Deeper waters might dampen the phenomenon, but the volcano’s surface is only 150 to 200 meters underwater.
How is the local situation now?
It is difficult to assess the scale of the damage due to the severe disruption of communications with Tonga.
The port of Tonga’s capital, Nukuʻalofa, was severely damaged, and many buildings facing the sea were completely razed to the ground.
Tonga eruption: why we still haven’t grasped its impact?
Main port facilities in Tonga after volcanic eruption
Drag the button left or right to see how Nuku’alofa is affected.
Your device may not support this visualisation
Although the seaside area of Nuku’alofa was damaged, according to current information, the interior is largely untouched.
Residents of the smaller, lower island north of Tongatapu, the main island of Tonga, are also receiving increasing attention.
volcanic eruptionsPost Tongasettlementcovered in volcanic ash
Drag the button left or right to viewmain island of Tongaaffected.
Your device may not support this visualisation
Tongan authorities said all the houses on one island, home to about 50 people, were destroyed, while on another island only two remained. Other islands also suffered severe damage, they said.
Volunteers have been cleaning runways at major airports to allow planes to bring emergency drinking water and supplies to the ground.
Volcanic ash covers houses and buildings after volcano eruption
Drag the button left or right to viewTonga residential areaaffected.
Your device may not support this visualisation
Tonga settlements no longer visible after volcano eruption
Drag the button left or right to viewNorth of the main island of Tongaaffected.
Your device may not support this application
New Zealand’s Defence Minister Peeni Henare told the BBC that New Zealand had recently sent two navy ships to Tonga, expected to arrive in the next few days.
“It will take about three to four days to sail to Tonga and they will have plenty of water, food and medical supplies,” he said.