{"id":12710,"date":"2024-09-25T22:00:00","date_gmt":"2024-09-25T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=12710"},"modified":"2024-09-15T17:22:58","modified_gmt":"2024-09-15T17:22:58","slug":"the-skyscraper-sized-tsunami-that-vibrated-through-the-entire-planet-and-no-one-saw","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/the-skyscraper-sized-tsunami-that-vibrated-through-the-entire-planet-and-no-one-saw\/","title":{"rendered":"The\u00a0skyscraper-sized\u00a0tsunami that vibrated through the entire planet and no one\u00a0saw"},"content":{"rendered":"\n
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\n Dickson Fjord in August 2023. Just a few weeks later, a large chunk of the mountain would slide into the ocean.\n Wieter Boone \/ Flanders Marine Institute<\/span><\/span>\n <\/figcaption>\n <\/figure>\n\n Stephen Hicks<\/a>, UCL<\/a><\/em> and Kristian Svennevig<\/a>, Geological Survey of Denmark and Greenland<\/a><\/em><\/span>\n\n

Earthquake scientists detected an unusual signal on monitoring stations used to detect seismic activity during September 2023. We saw it on sensors everywhere, from the Arctic to Antarctica.<\/p>\n\n

We were baffled \u2013 the signal was unlike any previously recorded. Instead of the frequency-rich rumble typical of earthquakes, this was a monotonous hum, containing only a single vibration frequency. Even more puzzling was that the signal kept going for nine days.<\/p>\n\n

\n \"Map<\/a>\n
\n Dickson Fjord is surrounded by steep mountains.<\/span>\n Uwe Dedering \/ wiki<\/span>, CC BY-SA<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

Initially classified as a \u201cUSO\u201d \u2013 an unidentified seismic object \u2013 the source of the signal was eventually traced back to a massive landslide in Greenland\u2019s remote Dickson Fjord. A staggering volume of rock and ice, enough to fill 10,000 Olympic-sized swimming pools, plunged into the fjord, triggering a 200-metre-high mega-tsunami and a phenomenon known as a seiche: a wave in the icy fjord that continued to slosh back and forth, some 10,000 times over nine days. <\/p>\n\n

To put the tsunami in context, that 200-metre wave was double the height of the tower that houses Big Ben in London and many times higher than anything recorded after massive undersea earthquakes in Indonesia in 2004 (the Boxing Day tsunami) or Japan in 2011 (the tsunami which hit Fukushima nuclear plant). It was perhaps the tallest wave anywhere on Earth since 1980<\/a>.<\/p>\n\n

Our discovery, now published in the journal Science<\/a>, relied on collaboration with 66 other scientists from 40 institutions across 15 countries. Much like an air crash investigation, solving this mystery required putting many diverse pieces of evidence together, from a treasure trove of seismic data, to satellite imagery, in-fjord water level monitors, and detailed simulations of how the tsunami wave evolved.<\/p>\n\n

\n \"Gif<\/a>\n
\n Before and after the landslide-tsunami.<\/span>\n Before: Wieter Boone \/ Flanders Marine Institute; After: Danish military<\/span><\/span>\n <\/figcaption>\n <\/figure>\n\n

This all highlighted a catastrophic, cascading chain of events, from decades to seconds before the collapse. The landslide travelled down a very steep glacier in a narrow gully before plunging into a narrow, confined fjord. Ultimately though it was decades of global heating that had thinned the glacier by several tens of meters, meaning that the mountain towering above it could no longer be held up.<\/p>\n\n

Uncharted waters<\/h2>\n\n

But beyond the weirdness of this scientific marvel, this event underscores a deeper and more unsettling truth: climate change is reshaping our planet and our scientific methods in ways we are only beginning to understand.<\/p>\n\n

It is a stark reminder that we are navigating uncharted waters. Just a year ago, the idea that a seiche could persist for nine days would have been dismissed as absurd. Similarly, a century ago, the notion that warming could destabilise slopes in the Arctic, leading to massive landslides and tsunamis happening almost yearly, would have been considered far-fetched. Yet, these once-unthinkable events are now becoming our new<\/a> reality<\/a>.<\/p>\n\n

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