How Giant Tsunamis Work?

they come unexpectedly grow to the size of a multi-story building and destroy everything in their path taking thousands of lives no these aren't monsters from popular films i'm talking about ordinary sea water that suddenly gathers into a tsunami if you think they'll never concern you i wouldn't be so sure how do you recognize such an impending threat and how does the ocean produce such killer waves a tsunami's biggest danger is its suddenness it's no wonder that in japanese tsunami means wave in the harbor they say it was thought up by fishermen returning with their catch they saw that their port had been destroyed by a fierce wave they hadn't even seen the fact is that in the open ocean tsunamis are usually no higher than a meter or 3.3 feet but in length that is the distance between the ridges they can reach from between 100 to 200 kilometers or 60 to 120 miles that's at least a thousand times larger than ordinary waves and their speed is like that of a jet plane and only on the coasts do tsunamis grow to incredible sizes so how do we explain this sudden fury of the elements the wind as in the case of ordinary waves has nothing to do with it the mass of water is literally pushed by a short powerful impulse from underwater and a large scale sharp shift in the ocean occurs the cause may be an earthquake volcanic eruption landslide explosion the collapse of rocks and glaciers or asteroids impacting the water but the main culprit in 88 of cases is seismic the driving energy of a tsunami unlike an ordinary wave passes through the water not on top of it so 95 of the life cycle of a tsunami is invisible to the eye and only at its end does it come to the surface now take a deep breath and dive deep into the very epicenter of these events with me to the moment that the lithospheric plates of the earth's crust shift the shake is powerful almost eight points which means that a tsunami can't be avoided because of the shock part of the sea floor rises while another drops and the ocean begins oscillating vertically launching a series of waves if a ship is sitting above the center of this earthquake it's safe the height of the waves beating on its side is about half a meter or 1.64 feet but in the depths of the ocean everything is shaking from the bottom to the surface imagine the huge mass of water now rushing to the coast and at a speed of between 400 to 880 kilometers an hour that's between 249 to 547 miles an hour and in some cases up to a thousand kilometers an hour that's 621 miles an hour what will you see from the shore if you're waiting for a killer wave like in disaster films then you may not be ready for what will really happen and you yourself will certainly meet your death transfixed by the unusual behavior of the water before a tsunami it often recedes exposing the coast due to the land settling at the site of the earthquake so the worst thing you can do at this moment is start collecting shells and animals from the seabed that's what many people have done when encountering a tsunami for the first time meanwhile off the coast part of the wave slows down to 50 kilometers or 31 miles an hour and the rest of the water mass begins rising due to the congestion the deeper the ocean the higher the crest and the farther the water recedes the more grandiose the tsunami but now that you know the reason for this strange behavior you can warn others of the impending catastrophe as the english school girl tilly smith did at the coast of the indian ocean in 2004 by a lucky coincidence she had just learned in geography class that the water quickly retreats from the shore before a tsunami tilly convinced her parents and everyone around that they needed to save themselves and thus helped about a hundred people keep in mind that you have to act quickly despite slowing down once the wave reaches the shore its speed is still tens of kilometers or miles per hour so by the time an alarm is issued or a tsunami appears on the horizon you have a maximum of 20 minutes spend it retreating 10 kilometers or 6.2 miles inland if that's not possible climb up onto a roof or at least a strong tree a car isn't always the best choice you don't want to get stuck in traffic among all the others fleeing the elements do you if you find yourself in water then first of all get rid of heavy shoes and clothes you could easily be hit by debris and be carried into the ocean and in such clothes it would be extremely difficult to escape also don't rush to joyfully return to the danger zone once the water recedes this is what residents of the soviet city of severo kurilsk did during a tsunami in 1952 as a result those who survived the first wave were swept away a half an hour later with the second which was about 15 to 18 meters or 49 to 59 feet tall alas that's not uncommon there are several waves and the first isn't always the largest the next may not arrive for two to three hours and it won't face any obstacles the first wave clears the path taking cars trees and property with it the second one carries it all back destroying buildings and anything in its way this is exactly what happened in several grielsk tremors began at about four a.m and when the morning fog cleared fragments floating in the water were the only remnants left of the city on the shore therefore not until three to four hours after the final attack can you finally take a breath but don't think that for salvation it's enough to notice only the strange behavior of the water in time it doesn't always recede before a tsunami so relying on this sign alone isn't enough the most accurate information about the threat will be provided by tsunami warning centers the fact is that seismic waves move much faster than normal waves and an alarm from such a center gives coastal residents a couple of precious minutes sometimes even hours if the source of the earthquake is far from the coast yet not all strong underwater quakes lead to tsunamis an increase in water level in a particular area of the sea or ocean will give the most accurate forecast and it's important that the alarm from the measuring point comes no later than the wave itself while we discuss underwater earthquakes you shouldn't discount other causes of tsunamis for example the world's largest tsunami ever occurred in alaska 90 million tons of rock and ice fell from the mountains into the bay water shot up 524 meters or 1720 feet into the air a wave swept across the bay ripping out trees and throwing one ship which sat 10 kilometers or 6.2 miles from the epicenter across the island and the tsunami resulting from the eruption of the indonesian volcano krakatoa in the 19th century destroyed thousands of ships and claimed tens of thousands of lives although according to statistics volcanoes are the cause of about only five percent of such disasters not only can killer waves be created by nature but also by mankind itself for example by blowing up an underwater atomic bomb as it happened in the mid 20th century an explosion at depth lifted a wave 29 meters or 95 feet high however there was no damage after breaking 300 meters or 984 feet it calmed down the rarest cause of tsunamis are asteroids with a diameter of more than one kilometer or 0.62 miles falling into the water for example according to one version the cheek salub asteroid with a diameter of between 11 to 81 kilometers or 6.8 to 50.3 miles and with a crater 20 kilometers or 12 miles deep caused the extinction of dinosaurs it deprived the earth of sunlight due to the release of dust into the atmosphere and triggered a tsunami 14 meters to 1.5 kilometers or 46 feet to 0.93 miles high these waves swept across the planet stirring up the oceans the deadliest one was the already mentioned tsunami near the island of sumatra in 2004. it touched 14 countries and claimed more than 200 000 lives the energy from the earthquake that triggered it amounted to 20 000 atomic bombs like the one dropped on hiroshima if you've made plans for a future vacation but are suddenly hesitating don't rush to postpone it first of all the biggest danger in terms of tsunamis is the pacific ocean area called the ring of fire and secondly in terms of small waves even there they usually occur no more than four times a year and only once a decade record holders with a height of 10 meters or about 30 feet are born have you ever witnessed a tsunami or other natural disaster let us know in the comments if you liked the video give it a thumbs up subscribe to the channel click on the bell to receive notifications for new videos and don't forget to recommend us to your friends

Channel: Ridddle

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Keywords: Ridddle, riddle, sci, science, smart, experiment, tsunami, japan tsunami, giant tsunami, megatsunami, earthquake, wave

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Length: 10min 43sec (643 seconds)

Published: Sun Aug 16 2020

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See also: Tsunamis