Jan 17, 2022 11:45 PM
(This post was last modified: Jan 18, 2022 01:36 AM by C C.)
The most explosive eruption in 30 years, Hunga Tonga-Hunga Ha’apai rewrites tsunami rules
https://www.stuff.co.nz/national/explain...nami-rules
EXCERPT: . . . the tsunami didn’t dissipate as would have been expected. “Prior to this, I would have said, yeah, a volcanic tsunami could cause damage maybe 200 or 300 kilometres away from the volcano,” Lane said. “But we're seeing boats being destroyed in New Zealand, in Japan, there were cars and boats being washed away and boats being destroyed in the US. These are all thousands of kilometres away from this volcano, so that's an incredible amount of energy that's been blown out to cause that.” (MORE - missing details)
After Volcano, Tongans Abroad Wait for News From Home
https://www.nytimes.com/2022/01/17/world...lcano.html
INTRO: Two days after a colossal volcanic eruption spawned a tsunami that struck the island nation of Tonga, severed communication lines left Tongans around the world waiting anxiously for news of their loved ones, while aid agencies and the country’s Pacific neighbors struggled to assess the scale of the damage.
On Saturday night, an undersea volcano about 40 miles north of Tonga’s main island belched ash, gas and steam more than 12 miles into the air, creating a cloud of sulfur dioxide over the region, sending particles drifting across the island and disabling a crucial submarine internet cable. It was believed to be the largest volcanic eruption in three decades, with the shock wave traveling thousands of miles.
Hours later, Tonga, a country of around 100,000 people, was pummeled by a tsunami. Waves of up to four feet hit Nuku’alofa, the Tongan capital. Footage shared in the final moments before the internet connection was cut showed people running inland, searching desperately for higher ground in a very flat country.
The volcano, Hunga Tonga-Hunga Ha’apai, erupted again on Monday but did not trigger a tsunami warning. Tonga sits along the Pacific “Ring of Fire,” a series of fault lines where earthquakes and volcanic activity are frequent.
Fatafehi Fakafanua, the speaker of the Legislative Assembly of Tonga, was able to send out a message on social media on Monday, describing the tsunami’s impact as “devastating” and noting that the fall of volcanic ash had affected many areas of the country.
“The full extent of the harm to lives and property is currently unknown,” he said. “What we do know is that Tonga needs immediate assistance to provide its citizens with fresh drinking water and food.”
The loss of most communications, as well as a lingering ash cloud that had reached some 63,000 feet high, have made it difficult for the outside world to get a picture of the situation in Tonga... (MORE - details)
Why the volcanic eruption in Tonga was so violent, and what to expect next
https://theconversation.com/why-the-volc...ext-175035
EXCERPTS: The Kingdom of Tonga doesn’t often attract global attention, but a violent eruption of an underwater volcano on January 15 has spread shock waves, quite literally, around half the world.
The volcano is usually not much to look at. It consists of two small uninhabited islands, Hunga-Ha’apai and Hunga-Tonga, poking about 100m above sea level 65km north of Tonga’s capital Nuku‘alofa. But hiding below the waves is a massive volcano, around 1800m high and 20km wide.
The Kingdom of Tonga doesn’t often attract global attention, but a violent eruption of an underwater volcano on January 15 has spread shock waves, quite literally, around half the world.
The volcano is usually not much to look at. It consists of two small uninhabited islands, Hunga-Ha’apai and Hunga-Tonga, poking about 100m above sea level 65km north of Tonga’s capital Nuku‘alofa. But hiding below the waves is a massive volcano, around 1800m high and 20km wide.
The Hunga-Tonga-Hunga-Ha'apai volcano has erupted regularly over the past few decades. During events in 2009 and 2014/15 hot jets of magma and steam exploded through the waves. But these eruptions were small, dwarfed in scale by the January 2022 events.
Our research into these earlier eruptions suggests this is one of the massive explosions the volcano is capable of producing roughly every thousand years.
[...] The two earlier eruptions on December 20 2021 and January 13 2022 were of moderate size. They produced clouds of up to 17km elevation and added new land to the 2014/15 combined island.
The latest eruption has stepped up the scale in terms of violence. The ash plume is already about 20km high. Most remarkably, it spread out almost concentrically over a distance of about 130km from the volcano, creating a plume with a 260km diameter, before it was distorted by the wind.
[...] The eruption also produced a tsunami throughout Tonga and neighbouring Fiji and Samoa. Shock waves traversed many thousands of kilometres, were seen from space, and recorded in New Zealand some 2000km away. Soon after the eruption started, the sky was blocked out on Tongatapu, with ash beginning to fall.
All these signs suggest the large Hunga caldera has awoken. Tsunami are generated by coupled atmospheric and ocean shock waves during an explosions, but they are also readily caused by submarine landslides and caldera collapses.
It remains unclear if this is the climax of the eruption. It represents a major magma pressure release, which may settle the system.
A warning, however, lies in geological deposits from the volcano’s previous eruptions. These complex sequences show each of the 1000-year major caldera eruption episodes involved many separate explosion events.
Hence we could be in for several weeks or even years of major volcanic unrest from the Hunga-Tonga-Hunga-Ha'apai volcano. For the sake of the people of Tonga I hope not. (MORE - missing details)
https://www.stuff.co.nz/national/explain...nami-rules
EXCERPT: . . . the tsunami didn’t dissipate as would have been expected. “Prior to this, I would have said, yeah, a volcanic tsunami could cause damage maybe 200 or 300 kilometres away from the volcano,” Lane said. “But we're seeing boats being destroyed in New Zealand, in Japan, there were cars and boats being washed away and boats being destroyed in the US. These are all thousands of kilometres away from this volcano, so that's an incredible amount of energy that's been blown out to cause that.” (MORE - missing details)
After Volcano, Tongans Abroad Wait for News From Home
https://www.nytimes.com/2022/01/17/world...lcano.html
INTRO: Two days after a colossal volcanic eruption spawned a tsunami that struck the island nation of Tonga, severed communication lines left Tongans around the world waiting anxiously for news of their loved ones, while aid agencies and the country’s Pacific neighbors struggled to assess the scale of the damage.
On Saturday night, an undersea volcano about 40 miles north of Tonga’s main island belched ash, gas and steam more than 12 miles into the air, creating a cloud of sulfur dioxide over the region, sending particles drifting across the island and disabling a crucial submarine internet cable. It was believed to be the largest volcanic eruption in three decades, with the shock wave traveling thousands of miles.
Hours later, Tonga, a country of around 100,000 people, was pummeled by a tsunami. Waves of up to four feet hit Nuku’alofa, the Tongan capital. Footage shared in the final moments before the internet connection was cut showed people running inland, searching desperately for higher ground in a very flat country.
The volcano, Hunga Tonga-Hunga Ha’apai, erupted again on Monday but did not trigger a tsunami warning. Tonga sits along the Pacific “Ring of Fire,” a series of fault lines where earthquakes and volcanic activity are frequent.
Fatafehi Fakafanua, the speaker of the Legislative Assembly of Tonga, was able to send out a message on social media on Monday, describing the tsunami’s impact as “devastating” and noting that the fall of volcanic ash had affected many areas of the country.
“The full extent of the harm to lives and property is currently unknown,” he said. “What we do know is that Tonga needs immediate assistance to provide its citizens with fresh drinking water and food.”
The loss of most communications, as well as a lingering ash cloud that had reached some 63,000 feet high, have made it difficult for the outside world to get a picture of the situation in Tonga... (MORE - details)
Why the volcanic eruption in Tonga was so violent, and what to expect next
https://theconversation.com/why-the-volc...ext-175035
EXCERPTS: The Kingdom of Tonga doesn’t often attract global attention, but a violent eruption of an underwater volcano on January 15 has spread shock waves, quite literally, around half the world.
The volcano is usually not much to look at. It consists of two small uninhabited islands, Hunga-Ha’apai and Hunga-Tonga, poking about 100m above sea level 65km north of Tonga’s capital Nuku‘alofa. But hiding below the waves is a massive volcano, around 1800m high and 20km wide.
The Kingdom of Tonga doesn’t often attract global attention, but a violent eruption of an underwater volcano on January 15 has spread shock waves, quite literally, around half the world.
The volcano is usually not much to look at. It consists of two small uninhabited islands, Hunga-Ha’apai and Hunga-Tonga, poking about 100m above sea level 65km north of Tonga’s capital Nuku‘alofa. But hiding below the waves is a massive volcano, around 1800m high and 20km wide.
The Hunga-Tonga-Hunga-Ha'apai volcano has erupted regularly over the past few decades. During events in 2009 and 2014/15 hot jets of magma and steam exploded through the waves. But these eruptions were small, dwarfed in scale by the January 2022 events.
Our research into these earlier eruptions suggests this is one of the massive explosions the volcano is capable of producing roughly every thousand years.
[...] The two earlier eruptions on December 20 2021 and January 13 2022 were of moderate size. They produced clouds of up to 17km elevation and added new land to the 2014/15 combined island.
The latest eruption has stepped up the scale in terms of violence. The ash plume is already about 20km high. Most remarkably, it spread out almost concentrically over a distance of about 130km from the volcano, creating a plume with a 260km diameter, before it was distorted by the wind.
[...] The eruption also produced a tsunami throughout Tonga and neighbouring Fiji and Samoa. Shock waves traversed many thousands of kilometres, were seen from space, and recorded in New Zealand some 2000km away. Soon after the eruption started, the sky was blocked out on Tongatapu, with ash beginning to fall.
All these signs suggest the large Hunga caldera has awoken. Tsunami are generated by coupled atmospheric and ocean shock waves during an explosions, but they are also readily caused by submarine landslides and caldera collapses.
It remains unclear if this is the climax of the eruption. It represents a major magma pressure release, which may settle the system.
A warning, however, lies in geological deposits from the volcano’s previous eruptions. These complex sequences show each of the 1000-year major caldera eruption episodes involved many separate explosion events.
Hence we could be in for several weeks or even years of major volcanic unrest from the Hunga-Tonga-Hunga-Ha'apai volcano. For the sake of the people of Tonga I hope not. (MORE - missing details)
![[Image: IqT2t0KL?format=jpg&name=large]](https://pbs.twimg.com/card_img/1780800301152260096/IqT2t0KL?format=jpg&name=large)