What if there was a megatsunami and nobody noticed ? It almost happened last year , when a rockslide occur halfway up Greenland ’s east coast . The waving produced was initially 200 meter ( 650 feet ) high , yet they get under one’s skin very small coverage – we must confess , IFLScience drop it as well . In our DoD , no one was hurt and it is only now that scientists have reported the most interesting part of the issue ; the creation of a second type of wave that keep back the waters of a fjord oscillating for a week .
The tsunamis we are most intimate with are because of volcanoes or undersea earthquakes . Tsunamis can also be triggered by stone falling into the ocean – most dramatically in the case of the encroachment that killed most dinosaurs , but ordinarily triggered by avalanches . This sort of tsunami is surprisingly common – one in 1958 triggered thehighest wavesever recorded .
We seldom discover about events like this because they most often pass where water ice is abundant , such as near the pole . therefore , six days after a megatsunami 100 metre ( 330 human foot ) highdevastated a small communityin West Greenland , another one struck on the diametric coast . But when Angela Carrillo - Ponce of GFZ German Research Centre for Geoscience and confrere examined the seismal data , they notice something unusual .
As this aerial photo shows, Dickson fjord is long but narrow, creating a resonating column for waves moving between the side walls.Image Credit: TSR (2024) Carrillo-Ponce et al
A sign could be observed from the initial swift release of a great passel of energy , but it was accompanied by a 2d note , known as a very farseeing - geological period ( VLP ) signal . This , the squad base , was from a seiche – a remain firm wave that makes a body of pee oscillate . You might be familiar with seiches from the astonishing discovery of a fossil bed make by one onthe day the dinosaur diedor the rest home of theworld ’s rare fish . You might also have made one in your bathroom as a small fry if you force the water around at a frequency that oppose the resonance of the container , or produced one in physic socio-economic class as your instructor demonstrated standing waves .
The one these researchers get is on a different scale , timewise , however . “ The fact that the signal of a rockslide - triggered splosh wafture in a remote expanse of Greenland can be observe worldwide and for over a week is exciting , and as seismologists this sign was what mostly caught our care , ” Carrillo - Ponce said in astatement . “ The analysis of the seismic signal can give us some resolution regarding the processes involved and may even lead to improved monitoring of similar effect in the futurity . If we had not study this result seismically , then we would not have known about the seiche produced in the fjord organization . ”
societal media postal service provide scientist with the first indication something big had happened on Greenland ’s east coast , follow by reports of large Wave from the ( unoccupied at the clip ) Danish naval foot on nearby Ella Island .
The origins of the tsunami were traced to a side vale of Dickson Fjord , where planet range reveal a here - yesterday - buy the farm - today spell of rocks pose 300 - 400 meters ( 984 - 1,312 foundation ) above the waterline . Researchers determined that a landslip sweep a mix of glacier chalk and rock into the water and around 1.6 km ( 1 mile ) along the valley until it reached the fjord proper .
No one see what happened to the water within the fjord . seismal information suggest the initial tsunami was still around 60 meters ( 200 feet ) high as it traveled most of the inlet ’s length , but it faded cursorily once it reached the open sea .
However , some of the energy recoil back and forward within the 20 - klick ( 12 - international nautical mile ) long and 2 - kilometer ( 1.2 - knot ) wide fjord , produce a seiche . The seiche was initially about 2.6 meters ( 9 pes ) in high spirits , and jounce back and off between the side walls with a point of a small less than two minutes , fading exceptionally slowly .
Icefalls have created VLP signals we have detected previously , but this one ’s distance startle researchers , particularly given the distance to station that could observe it . “ It is quite impressive to see that we could use good - quality data from station located as far as Germany , Alaska and North America , and that those records were unattackable enough for at least one week , ” Carrillo Ponce articulate .
A tsunami can be considered " mega " if it ismore than100 meters ( 330 understructure ) high at the source , even if it speedily diminish below that stratum
The field is publish loose access inThe Seismic Record .
