Announcement

Collapse
No announcement yet.

Saturday's Tonga Volcano Details

Collapse
X
Collapse
  •  

  • Saturday's Tonga Volcano Details




    The eruption of the Hunga-Tonga-Hunga-Ha'apai volcano on Saturday was so large, it was a spectacle best appreciated from space.

    The eruption was remarkable in that it involved the simultaneous formation of a volcanic ash plume, an atmospheric shock wave and a series of tsunami waves.
    While details are still emerging and we are still within an eruption episode that could have more twists and turns, there are several pieces of information that can help us begin to understand this event and why it occurred.

    Story By Shane Cronin /CNN.com


    M 5.8 Volcanic Eruption - 68 km NNW of Nuku‘alofa, Tonga
    2022-01-15 04:14:45 (UTC)20.546°S 175.390°W0.0 km depth





    First, let's look at the eruption. Events of this magnitude occur roughly once a decade around the world, but for this volcano an eruption of this scale is a rarity. Based on my research, using radiocarbon dating to examine the ash and deposits from past eruptions, it seems this latest eruption is a once-in-a-millennium event for the Hunga-Tonga-Hunga-Ha'apai volcano.
    It takes roughly 900-1000 years for the Hunga volcano to fill up with magma, which cools and starts to crystallize, producing large amounts of gas pressure inside the magma. As gases start to build up pressure, the magma becomes unstable. Think of it like putting too many bubbles into a champagne bottle -- eventually, the bottle will break.
    As the magma pressure rises, the cold and wet rock above the magma fails and suddenly releases the pent-up pressure. The eruption we saw on Saturday blasted rock, water, and magma 30 km high into the atmosphere, and was profound in terms of its energy. Within 30 minutes, the resulting cloud seen from space was over 350 km (or 218 miles) in diameter, with ash falling out onto several Tongan islands.
    As for tsunamis, they are most commonly caused by earthquakes. When tectonic plates shift under the ocean, it can displace enough water to cause massive waves. So how does a partially submerged volcano in the southwest Pacific create enough energy to produce tsunami waves that hit the West coast of the US?








    While it's still unclear what exactly caused the tsunami, there are at least two distinct possibilities -- and the first has to do with the expansive force of the initial eruption. On Saturday, the eruption of magma from the volcano created a sudden release of pressure, producing supersonic air pressure waves that could be seen from space.
    These air pressure waves traveled more than 2000 km (1,200 miles) to New Zealand and were felt as far as the United Kingdom and Finland.
    The atmospheric waves and the initial blast affected the ocean surface, causing the giant waves that then hit the Tongan island of Tongatapu and the capital of Nuku'alofa. Early videos showed the waves splashing over roads before the plume of ash darkened the sky.
    Another possible cause of the tsunami waves could have been the remarkable changes within the Hunga volcano. In the aftermath of the eruption, images from satellite radar imagery show the central part of the volcano which previously rose above sea level has since disappeared below the waves. This indicates when the eruption occurred, the sudden loss of magma likely caused the central portion of the volcano to collapse, creating a caldera, or a hollow depression. This collapse could have displaced the water, generating tsunami waves that radiated outwards across the Pacific and all the way to California.





    The Hunga eruption was also astounding in terms of all the lightning generated. This is caused by the electrostatic interaction of very fine volcanic "ash" particles in the air. Weather satellites and lightning researchers are calling this one of the most significant events they have ever seen, with lightning strikes peaking at 63,000 events per 15 minutes.
    Past eruptions from this volcano -- such as the 2014 eruption that created a new island -- included many phases of eruption, and thus we could see more explosions in the coming days and weeks. One moderating factor is the caldera is now underwater, making it harder for eruptions to break through into the atmosphere.
    This could mean a shift to more submarine-style explosive eruptions. While this would mean a smaller atmospheric impact, there could still be an elevated risk of tsunamis, and people who live in coastal areas around the Pacific should be on high alert in the coming weeks.
    Even though our past research has highlighted the importance of the power of eruptions at this volcano, predicting volcanic eruptions to the day and hour remains impossible. This is particularly difficult at a volcano so far offshore, with no power and a shifting, dynamic environment. The only observations are possible via satellite methods, which give a few minutes warning at best for the local residents of Tonga.


    They say every major eruption brings with it a new surprise. This event has shown us clearly volcanoes can be very effective at generating tsunami events, and while Tonga is a long way away from most other countries, its volcanoes can threaten low-lying areas of nations around the globe.
    Over the next days to weeks, we will learn more about this fascinating and dangerous volcano and also the hazards of submarine calderas. Early reports suggest Tonga has experienced significant damage due to tsunami, with many outlying areas still out of reach. We can only hope at the moment everyone in Tonga is safe and well.




    Santa Cruz Small Craft Harbor images © Mike Evans







      Posting comments is disabled.

    Latest Articles

    Collapse

    • The Vendee Season Begins With The Vendee Artique
      by Photoboy



      Alain Leboeuf, President of SAEM Vendee and of the Department of Vendee has just presented the very rich sports line-up of the 2nd edition of the Vendee Arctic – Les Sables d'Olonne, more than 2 years from the 10th edition of the Vendee Globe. The sporting and media successes of the 2020-2021 edition stimulated project leaders and their sponsors, so much so that the transition phase was particularly short. The Arctic Vend?e being the first of the five qualifying races*...
      Yesterday, 03:17 PM
    • The 4th Entry To The 2022-2023 Ocean Race IS:
      by Photoboy
      SIZE=18px]GUYOT environnement - Team Europe confirmed as fourth IMOCA entry for The Ocean Race


      The new campaign builds on a winning French-German collaboration from The Ocean Race Europe[/SIZE]




      ...
      Yesterday, 01:07 PM
    • United As One
      by Photoboy


      Racing in light conditions can often be boring and frustrating but for the penultimate day of the first ever IMA Maxi European Championship it was anything but – for spectators at least - with significant shifts, occasional shut-downs on a coastal course on a WSW-ENE axis deep into the Bay of Naples to the north of the Sorrentine peninsula.

      After a delay ashore and then on the water, the race for the 21 entries got underway just before 1500 CEST with a short upwind
      ...
      Yesterday, 09:23 AM
    • The Finn Leads At The 2022 Finn Gold Cup
      by Photoboy



      After three very different races, Finland’s Oskari Muhonen has taken the lead at the 2022 Finn Gold Cup at Fraglia Vela Malcesine on Lake Garda, Italy. He won two more races to take a three point lead from Pieter-Jan Postma, from The Netherlands. Austria’s Florian Raudaschl won the second race and moves up to third overall. Four races remain.

      After losing the first day with no wind, the event is back on schedule. But still the conditions defy the local
      ...
      05-19-2022, 02:19 PM
    • Lyra Making Waves At IMA Maxi Europeans
      by Photoboy





      Scheduled for day two of the IMA Maxi Europeans’ inshore/coastal racing were two windward-leewards. After a delay out on the Bay of Naples, the wind finally built to 8-12 knots from the west. After one aborted start due to a wind shift and another for a general recall, racing for the 21 maxis eventually got underway at 1515 CEST.





      All images copyright Studio Borlenghi IMA






      ...
      05-19-2022, 11:13 AM
    • Raza Mixta Declared 2022 Melges 2022 World Champions!
      by Photoboy



      May 15, 2022 - Fort Lauderdale, FL, USA - After two full years of hiatus in the schedule of the World Championships, the International Melges 24 Class returned to assign a most coveted World Title: it was October 2019 when in Villasimius Luca Perego’s Maidollis was crowned World Champion for the second time, and, after that moment the pandemic blocked everything, preventing the dispute of the 2020 and 2021 World Championship and the 2020 European Championship.
      ...
      05-16-2022, 09:34 AM
    Working...
    X