Het 'kleine' 2009 topic...quote:Op maandag 17 januari 2022 13:04 schreef heywoodu het volgende:
Het eiland is dus net geen 13 jaar oud geworden
https://en.wikipedia.org/(...)ea_volcanic_eruption
Je hebt brons gewonnen. 2 anderen waren je voorquote:Op maandag 17 januari 2022 16:13 schreef Ronzz het volgende:
Mogelijk opnieuw onderzeese vulkaanuitbarsting bij Tonga waargenomen
Bron
quote:Op zondag 16 januari 2022 22:23 schreef ACT-F het volgende:
Alweer een schokje? Zojuist uitgegeven:
[..]
https://tsunami.gov/event(...)/1/WEPA42/WEPA42.txt
quote:
Ja maar dat beeld op de onderste foto doet me denken aan de Krakatau en Santorini waar ook niets van over bleef (boven water dan) op een paar randjes/eilandjes na.quote:Op dinsdag 18 januari 2022 11:12 schreef Ener-G het volgende:
Ja bizar.. overigens is de caldera veeel groter en zijn die eilandjes maar een stukje van de rand van de krater van de originele vulkaan...
quote:Kans op nieuwe mega-explosie bij vulkaan Tonga klein, maar niet uitgesloten
De kans dat er de komende tijd opnieuw een enorme explosie plaatsvindt van de Hunga Tonga–Hunga Ha'apai-vulkaan bij Tonga is klein, maar is niet helemaal uitgesloten. Dat zeggen vulkanologen tegen NU.nl.
De vulkaan bij Tonga, op zo'n 17.000 kilometer van Nederland, barstte zaterdag uit en veroorzaakte op meerdere plekken in de wereld tsunami's. De enorme explosie zorgde voor een schokgolf die zelfs op instrumenten in Nederland waarneembaar was. As en rook werd ruim 20 kilometer de lucht ingeschoten.
De enorme explosie was het gevolg van drukopbouw over tientallen jaren, waarin magma zich vormt en ophoopt in magmakamers. Bij die vorming komt gas vrij, dat niet kan ontsnappen. "En dan kan het zijn dat de druk zó hoog wordt, dat dit er één keer uitkomt", zegt Janne Koornneef, vulkanoloog aan de Vrije Universiteit in Amsterdam. De hete magma kwam na de uitbarsting in contact met zeewater, waardoor er meteen een enorme rookontwikkeling ontstond.
Volgens Koornneef is de druk er na één grote explosie wel van af, maar weten we tegelijkertijd ook niet hoeveel magma er nog in de vulkaan zit. Dat zou weer voor een nieuwe eruptie kunnen zorgen. "Het lijkt er nu op dat de activiteit verdwenen is, maar een nieuwe explosie is niet te voorspellen."
Het monitoren van de Hunga Tonga is lastig omdat deze zich onder water bevindt, zegt KNMI-vulkanoloog Elske de Zeeuw-Van Dalfsen. "Dus je moet dan werken met meetinstrumenten en observaties van andere landen. Dat is niet zo makkelijk als bij een vulkaan op land waar je gewoon de instrumenten op kunt zetten."
Koornneef voegt daaraan toe dat er geen seismische activiteit was die wees op een aanstaande eruptie. Dat was bijvoorbeeld wel het geval bij de uitbarsting op La Palma. Of het met deze ene explosie klaar is, kunnen beide vulkanologen dan ook niet met zekerheid zeggen. "We weten dat er soms na één zo'n grote uitbarsting nog meer soortgelijke erupties komen, dus dat kunnen we nog niet niet uitsluiten", aldus De Zeeuw-Van Dalfsen.
Ja als de volgende radarscan is gemaakt van de situatie na de uitbarsting zal er hoogstens een randje vanaf zijn, van de hele vulkaan that is.quote:Op dinsdag 18 januari 2022 11:47 schreef Frutsel het volgende:
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Ja maar dat beeld op de onderste foto doet me denken aan de Krakatau en Santorini waar ook niets van over bleef (boven water dan) op een paar randjes/eilandjes na.
quote:Aswolk na uitbarsting vulkaan Tonga reikte tot 55 kilometer hoog
De aswolk die werd gevormd door de vulkaanuitbarsting bij Tonga bereikte de uitzonderlijke hoogte van zo'n 55 kilometer boven het aardoppervlak. Dat is grofweg halverwege de hoogte die door velen wordt gezien als het begin van de ruimte.
Britse wetenschappers hebben de hoogte van de aswolk berekend na het bestuderen van data van weersatellieten. Een van de onderzoekers, Simon Proud van de universiteit van Oxford, spreekt tegenover de BBC van een "ongekende hoogte" voor een aswolk.
Hieruit blijkt volgens hem de immense kracht die vrijkwam bij de uitbarsting van de onderzeese vulkaan. Ter vergelijking: een van de krachtigste vulkaanuitbarstingen in de afgelopen eeuw - die van Mount Pinatubo in de Filipijnen in 1991 - creëerde naar verluidt een aswolk van zo'n 40 kilometer hoog.
De uitbarsting bij Tonga werd ook opgepikt door alle 53 meetstations van de CTBTO, de internationale organisatie die vanuit Wenen in de gaten houdt of er ergens ter wereld nucleaire proeven worden gehouden.
Geofysicus Ronan Le Bras, verbonden aan de CTBTO, zegt tegen de Amerikaanse publieke radiozender NPR dat zelfs het meetstation op Antarctica de uitbarsting van de Hunga Tonga-Hunga Ha'apai opmerkte. Nooit registreerde de CTBTO zo'n sterke explosie op aarde sinds de oprichting van de organisatie in 1996.
Amerikaanse onderzoekers van ruimtevaartorganisatie NASA schatten de kracht van de uitbarsting eerder al op zo'n 10 megaton; dat is 500 keer krachtiger dan de atoombom waarmee de VS in 1945 Hiroshima verwoestte. Volgens Le Bras is dat een voorzichtige schatting van de werkelijke kracht waarmee Hunga Tonga-Hunga Ha'apai uitbarstte.
Kettingreactie
Wetenschappers weten nog niet waarom de explosie zo krachtig was. Tegen de BBC zegt een Nieuw-Zeelandse vulkanoloog dat de onderzeese uitbarsting in relatief ondiep water, gecombineerd met het directe contact van lava met het zeewater - dat meteen veranderde in stoom - mogelijk een soort kettingreactie veroorzaakte.
De uitbarsting van de Pinatubo in 1991 had tot gevolg dat de temperatuur op aarde gedurende een aantal jaren met ongeveer een halve graad daalde. Wetenschappers denken niet dat de uitbarsting van de vulkaan Hunga Tonga-Hunga Ha'apai een vergelijkbaar effect zal hebben. Er kwamen bij de eruptie namelijk aanzienlijk minder gassen vrij dan bij de Pinatubo.
Drinkwater geleverd
Zes dagen geleden barstte de Hunga Tonga-Hunga Ha'apai uit. De tsunami die werd veroorzaakt door de uitbarsting kostte op Tonga aan zeker drie mensen het leven en vernielde complete dorpen.
In de dagen daarna was er vooral veel onduidelijk over de situatie op Tonga, omdat onderzeese kabels waren beschadigd door de eruptie en communicatie daardoor nagenoeg onmogelijk was. Verder was het vliegveld bedekt met een dikke aslaag.
quote:Volcano Damage to Tonga Undersea Cable Worse Than Expected
NUKU'ALOFA, TONGA —
The volcanic eruption near Tonga shredded an 80-kilometer (50 mile) stretch of undersea cable, complicating efforts to reconnect the Pacific kingdom after a month of digital darkness, the company overseeing repairs says.
Tonga Cable Limited chief executive James Panuve said a repair ship had located the severed ends of the 840-kilometer-long cable linking Tonga to Fiji that was cut in the January 15 blast.
But rather than a clean break, Panuve said the ship found the eruption tore an 80-kilometer section of cable into numerous pieces as it pummeled the seabed with the explosive force of a nuclear bomb.
"It is obvious that the eruption, shockwaves, (and) tsunami caused major havoc underwater," he said Tuesday.
The eruption of the Hunga Tonga-Hunga Ha'apai volcano generated large tsunami waves and blanketed Tonga in toxic ash, claiming three lives.
Disaster relief efforts in the island nation of about 100,000 have been complicated by poor communications, with backup satellite links providing patchy broadband as the operation to repair the cable proceeds.
Panuve said that after contending with poor weather last week, the cable repair ship "Reliance" was now trying to retrieve sections of cable in waters up to 2.5 kilometers deep.
He said one section had been moved 5 kilometers by the undersea blast and another was buried under 30 centimeters of silt.
Despite the difficulties, Panuve was optimistic Tonga Cable could still meet its goal of repairing the digital link by February 20, saying plans were under way to create a "mini-system" to bridge the 80-kilometer gap.
Panuve said a piece of cable more than 55 kilometers long was still lost on the seabed and the ship was searching for it in the hope it was still usable.
In addition to the damage caused by the eruption and subsequent tsunamis, Tonga is also dealing with a COVID-19 outbreak after remaining virus free for much of the pandemic.
The main island Tongatapu and outlying Vava'u remain under lockdown with health authorities Tuesday reporting a total of 139 cases nationwide.
International humanitarian aid continues to arrive, with two Chinese naval vessels this week delivering 1,300 tons of supplies, including 500 prefabricated houses.
quote:How the Tonga volcano eruption from 2022 may affect Australia's weather for up to eight years
Lasting impacts from an enormous volcanic eruption a year ago may have a cooling and rainy influence on parts of Australia for up to eight years, according to scientists.
In January 2022, the underwater volcano Hunga Tonga-Hunga Ha'apai erupted, shooting ash and other particles more than half way to space.
The eruption triggered a tsunami that reached heights of more than 19 metres above sea level, and created long lasting and vivid sunsets for several months following.
But the powerful explosion also caught the intrigue of scientists around the globe, fascinated by its potential impacts on climate.
Of particular interest was the record-breaking amount of water vapour, a strong greenhouse gas, which it pumped into the stratosphere.
So a year on, what do we know about its influence on Australian weather?
Volcano potentially added to rain on east coast
Martin Jucker, from the University of New South Wales Climate Change Research Centre, is leading a research paper exploring the impacts of the eruption's water vapour on Australian weather.
The paper is currently at peer review stage.
Dr Jucker said while it was too early to provide solid answers with the paper still under review, they did have some idea about what the impacts might be on weather in Australia.
These included a potential increase in rainfall over the east coast of Australia, south of about Brisbane, between mid-February 2022 and mid-April 2022.
"So we can say, around March, April last year, the volcano would probably have favoured rain in Australia on the east coast," he said
This was by moving a large band of cloud, known as the South Pacific Convergence Zone (SPCZ), closer to Australia.
"The South Pacific Convergence Zone is where it rains a lot," Dr Jucker said.
"It's basically constantly cloudy.
"And so if that moves further south-west, that move means this band of rain moves closer to the (Australian) coast."
Dr Jucker said they were "quite confident" about the correlation between the eruption and the shift in position of the SPCZ."
But he said they could not put a figure on how much of an influence on rainfall it had during that time.
This was because it was too hard to untangle from other factors, such as La Nina, climate change and natural variability.
He said they also could not link it to a specific weather event, such as the Lismore flooding which occurred during this period, for the same reasons.
Possible cooling in WA and northern Australia
Dr Jucker said there could also be impacts to temperature for up to eight years because of how long it takes for particles to clear out of the stratosphere.
While our day-to-day weather occurs in the troposphere, the bottom layer of the atmosphere, conditions in the stratosphere can have flow-on impacts to how weather systems at the surface behave.
quote:Tonga Underwater Volcano Eruption Disrupted Satellite Signals Halfway Around the World
Research shows that volcanic eruptions can create plasma bubbles in the ionosphere, significantly disrupting satellite communication. These findings prompt revisions to the current models on atmospheric and ionospheric interactions.
An international team has used satellite- and ground-based ionospheric observations to demonstrate that an air pressure wave triggered by volcanic eruptions could produce an equatorial plasma bubble (EPB) in the ionosphere, severely disrupting satellite-based communications. Their findings will be published today (May 22) in the journal Scientific Reports.
The ionosphere is the region of the Earth’s upper atmosphere where molecules and atoms are ionized by solar radiation, creating positively charged ions. The area with the highest concentration of ionized particles is called the F-region, an area 150 to 800 km above the Earth’s surface. The F-region plays a crucial role in long-distance radio communication, reflecting and refracting radio waves used by satellite and GPS tracking systems back to the Earth’s surface.
These important transmissions can be disrupted by irregularities in the F-region. During the day, the ionosphere is ionized by the Sun’s ultraviolet radiation, creating a density gradient of electrons with the highest density near the equator. However, disruptions to this, such as the movement of plasma, electric fields, and neutral winds, can cause the formation of a localized irregularity of enhanced plasma density. This region can grow and evolve, creating a bubble-like structure called an EPB. EPB can delay radio waves and degrade the performance of GPS.
Since these density gradients can be affected by atmospheric waves, it has long been hypothesized that they are formed by terrestrial events such as volcanic activity. For an international team led by Designated Assistant Professor Atsuki Shinbori (he, him) and Professor Yoshizumi Miyoshi (he, him) of the Institute for Space–Earth Environmental Research (ISEE), Nagoya University, in collaboration with NICT, The University of Electro-Communications, Tohoku University, Kanazawa University, Kyoto University and ISAS, the Tonga volcano eruption offered them a perfect opportunity to test this theory
The Tonga volcano eruption was the biggest submarine eruption in history. This allowed the team to test their theory using the Arase satellite to detect EPB occurrences, the Himawari-8 satellite to check the initial arrival of air pressure waves and ground-based ionospheric observations to track the motion of the ionosphere. They observed an irregular structure of the electron density across the equator that occurred after the arrival of pressure waves generated by the volcanic eruption.
“The results of this study showed EPBs generated in the equatorial to low-latitude ionosphere in Asia in response to the arrival of pressure waves caused by undersea volcanic eruptions off Tonga,” Shinbori said.
The group also made a surprising discovery. For the first time, they showed that ionospheric fluctuations start a few minutes to a few hours earlier than the atmospheric pressure waves involved in the generation of plasma bubbles. This could have important implications because it suggests that the long-held model of geosphere-atmosphere-cosmosphere coupling, which states that ionospheric disturbances only happen after the eruption, needs revision.
“Our new finding is that the ionospheric disturbances are observed several minutes to hours before the initial arrival of the shock waves triggered by the Tonga volcanic eruption,” Shinbori said. “This suggests that the propagation of the fast atmospheric waves in the ionosphere triggered the ionospheric disturbances before the initial arrival of the shock waves. Therefore, the model needs to be revised to account for these fast atmospheric waves in the ionosphere.”
quote:Giant Eruption Plume from Tonga’s Volcano Produced Most Intense Lightning Rates Ever Detected
On January 15, 2022, Hunga Volcano in Tonga produced the most violent eruption in the modern satellite era, sending a water-rich plume at least 58 km (36 miles) high. This plume created record-breaking amounts of volcanic lightning observed both from space and by radio antennas on the ground thousands of kilometers away. New research shows that the eruption created more lightning — 2,615 flashes per minute at peak intensity — than any storm yet documented on Earth, including supercells and tropical cyclones. The peak lightning rate is significantly higher than the second most intense lightning event ever detected — 993 flashes per minute — in a thunderstorm over the southern United States in 1999.
An explosive eruption began on December 19, 2021 near the remote islands of Hunga Tonga and Hunga Ha’apai in the South Pacific Ocean.
These two islands are small peaks on the rim of a much larger submarine caldera volcano known as Hunga Volcano.
The explosive activity intensified on January 13, 2022, followed by the climactic eruption on January 15 that sent a water-rich volcanic plume into the mesosphere of our planet.
In addition to significant local impacts on the Kingdom of Tonga, the eruption created global-scale acoustic waves, tsunamis, ionospheric and geomagnetic disturbances, and warmed the climate due to water vapor injection.
The event continues to push the boundaries of our understanding of how explosive volcanism impacts the broader Earth system.
“This eruption triggered a supercharged thunderstorm, the likes of which we’ve never seen,” said lead author Dr. Alexa Van Eaton, a volcanologist at the U.S. Geological Survey.
“These findings demonstrate a new tool we have to monitor volcanoes at the speed of light and help the U.S. Geological Survey’s role to inform ash hazard advisories to aircraft.”
“The storm developed because the highly energetic expulsion of magma happened to blast through the shallow ocean.”
“Molten rock vaporized the seawater, which rose up into the plume and eventually formed electrifying collisions between volcanic ash, supercooled water and hailstones. The perfect storm for lightning.”
Combining data from sensors that measure light and radio waves, Dr. Van Eaton and colleagues tracked lightning flashes and estimated their heights.
The eruption produced just over 192,000 flashes (made up of nearly 500,000 electrical pulses), peaking at 2,615 flashes per minute.
Some of this lightning reached unprecedented altitudes in Earth’s atmosphere, between 20 to 30 km (12-19 miles) high.
“With this eruption, we discovered that volcanic plumes can create the conditions for lightning far beyond the realm of meteorological thunderstorms we’ve previously observed,” Dr. Van Eaton said.
“It turns out, volcanic eruptions can create more extreme lightning than any other kind of storm on Earth.”
The lightning provided insight into not only the duration of the eruption, but also its behavior over time.
“The eruption lasted much longer than the hour or two initially observed,” Dr. Van Eaton said.
“The January 15 activity created volcanic plumes for at least 11 hours. It was really only from looking at the lightning data that we were able to pull that out.”
The researchers saw four distinct phases of eruptive activity, defined by plume heights and lightning rates as they waxed and waned.
“The insights gained from linking lightning intensity to eruptive activity can provide better monitoring and nowcasting of aviation-related hazards during a large volcanic eruption, including ash cloud development and movement,” Dr. Van Eaton said.
quote:Tonga volcano triggered seafloor debris stampede
Last year's Tonga volcanic eruption produced the fastest underwater flows ever recorded, scientists say.
Huge volumes of rock, ash and mud were clocked moving across the ocean floor at speeds of up to 122km/h (75mph).
These "density currents", as they're known, snapped long sections of telecommunications cabling, cutting the Pacific kingdom's link to the global internet.
They also smothered and killed all sealife in their path.
It's another example of the prodigious scale of the 15 January eruption.
The underwater volcano called Hunga-Tonga Hunga-Ha'apai is already in the record books for:
the height of its eruption plume, which rose half way to space (58km) producing the biggest atmospheric disturbance in instrumented history triggering the most intense lightning storm - 2,600 flashes per minute
Scientists knew most of the roughly six cubic km of rock and ash thrown into the sky by the volcano must have come back down and spread out across the ocean floor, but now they've been able to map and measure its journey underwater and say something about its speed.
They did this by surveying and sampling the seafloor to see where the deposits went, and by comparing the timing of the eruption with the timing of the cable breaks.
There were two cables operational near the volcano, one connecting Tonga to the global internet and the other distributing this service to local islands.
The domestic cable, 50km from Hunga-Tonga, was the first to go down, 15 minutes after the onset of the main eruptive event. The international cable, some 70km away, followed about an hour later.
Researchers, led from the UK's National Oceanography Centre, say their investigations indicate the flow that broke the local submarine cable must have been moving at 73-122km/h (45-75mph); and even at the greater distance of the international cable, a velocity of 47-51km/h (29-32mph) is realistic.
"These flows hit the sweet spot for going as fast as they possibly could," said Dr Mike Clare, who is a co-lead author on a report in this week's Science Magazine.
"The rock and ash in the high eruption column fell down and went into the ocean like a jet. When this material hit the 40-degree slopes of the volcano flanks, it bit off chunks of the volcano and became even more dense. It walloped the domestic cable, was steered around corners and then walloped the international cable," he told the Science In Action programme on the BBC World Service.
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