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welcome back introduction to oceanography this is chapter 9 from essentials of Oceanography the seventh edition by Tom garrison and this chapter will be taking a look at ways waves transmit energy not water that's important waves to move water energy across the ocean waves are orbital almost like circles in which water molecules move and those closed for a bit as the wave moves by ocean waves are classified by the disturbing force that
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creates them the extent to which the deserving poor continues to influence a month their form and by the way of life is speed of a total weight is proportional to its wavelength something that's going to be a mathematical part of this chapter and we're going to see to see how late Lincoln speed change with ocean ways and most characteristics depend on the relationship between the mind and the depth of the water in which the trial your words of water molecules
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waves moving to water deeper than half the wavelength are unaffected by the bottom that means in deep water waves can be unaffected by the bottom the wailing of a tsunami in tighter so great that they're always affected by the box they're always continue considered be in shallow water and water displacement causes tsunamis and seismic see what can be very important we talk about earthquakes and what creates tsunamis should not be literally not noticeable
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in the ocean with a rush or like a sudden very high very huge lol waterways and are among the most illegal of our planet's natural phenomenon alright waves moving ocean waves do not move water they knew she waves are visual proof the transmission energy across the surface of the ocean to the right we did see a floating segal and it demonstrates the way a wave travels but the water is not you can see the wave moves from left to right the gulf in the water and which dressing
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room all literally historical slightly to the left of the front of the protein wave then to the cross and then sliding to the right back of the way and we can see how that works illustration below there's no mass transport
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mass transport nothing moved in and she moves through the water and so in the actual way there is this very small amount of movement which is now his Stoke strip manage the amount of transport that actually happened in reality there's a small net movement forward and that's known as doctorate and this contributes to the motion of wind driven service died 10 is between the property crash and the base the trial that can be the high frequency is
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the number of waves crash press one crashed his passing point a Barbie each second so for every press passes by four seconds to frequency and period is the time required for a wave crashed at point A here to read and again this is the orbital path of the individual water molecule underwater so we're always are ways in which the particles of water and Moon closed circles as a water passes know the water molecules in the crest of the wave moving the same direction as
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the way modules in the truck moved in the opposite direction but they also move more slowly the reason that the move more slowly is why you have that were rattled read or that sucks how to reclassify way scientists or you want to classify natural phenomenon so going to classify ways we have to wait type disturbing force the restoring force by the way things are going to classify the wave type as capillary waves when waves a seismic sea wave or a tsunami
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or a tie and the disturbing force of a capillary waves wind shear force also wind waves wind see a change in atmosphere pressure or a storm surge resizing seaway is faulting sea floor of a Russian or landslides and disturbing force of all times is the gravitational attraction of the Earth's rotation of the earth now what causes waves to set what disturbs waves these these issues what causes waves to go back to where they were
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capillary waves little tiny waves the cohesion of water molecules can actually bring them back down to flat and all other waves it's the restoring forces graphic now the typical labeling capillary waves is just very very small just over half of the typical way of learning how to win wave is anywhere between 200 500 feet and in the sea is going to be much larger variable as a function of the ocean basin they signed him seaway have a way to get the
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distance between craft can be as much about 25 miles and its whaling of the time is how the Earth's circumference so ocean waves are classified by the deserving poor state creates the extent to which the disarming force continues to influence the way once his farm and restoring forests and tried to the deserving poor us create the way it continues to influence the way and the restoring force is a force that tries to fly in the third way that they're going
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to be classified as by way of freeways propagated prosecution without further influence of the disturbing for so freeway is gonna be disturbed by when and continue to prostitution most wind waves are three ways force waves are maintained by the disturbing force otay or continue to be forced way and every turn Strikeforce is the dominant force that returns to service to fly away his former way to continue after they form because the restoring force over cotton
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seeds and create an oscillation so a wave once it leaves it is driving force continues because the restoring force tends to create over compensation meeting in May pulled away down the surface level but it also poses below the surface level and so responsibly going up above the surface level so waves that continues today for freeways do so because the restoring force open up over compensates and create an oscillation alright so this is how your
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typical win way this is going to be a very small when Wade reform but the transfer of wind energy into the water wind and waves grow from capillary way so all when we started capillary capillary wave forms as went friction literally the friction between the wind and the surface of the water stretches the water and service engine tried to restore the water structure and surface tension try to pull it back capillary waves in a row this movie service you flaking service when upward
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sloping cutting some of the winter transfer in the water to drive a capillary way press for essentially the way it flows across whitewater stretches to close it out and create is great County capillary way increasing energy and water service expand who or what all orbits of water particles moving in the direction of the wind and enlarges the wayside capillary waves forms anyway continued wind blowing the back of the capillary wave expand the orbits of water particles moving in the direction
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enlarges the way so so this is what it looks like the capillary waves with the win striking the water the surface of the water that is back as you getting the capillary waves continued with blind in the back of the capillary waves causes waves to continue and eventually the restoring force gravity pulls water down below the surface and it comes back up and you get the freeway continues so capillary waves become gravity waves as their Wavelink exceed 1.7 percent of
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what they get to about 1.7 for senators that you have these grabbing these these these freeway when induce rapid weight or wind waves continue to grow as long as i win above them exceeded speeds of the wind its way faster than a speeding away but we will continue to get bigger now when waves will exhibit a maximum 127 ratio of wave height to wavelength as the wave hi from the trial to the crosses the way way or the other
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wind wave exhibited maximum 127 ratio the angle of the craft will not exceed is one hundred and twenty to reach a peak here and he came as a continuous option of when it becomes higher than the 127 ratio it will break and that's really get why capsule winds will look like these peaks in the water and tea you get to this greater than 170 then you start white casts that occurs in what is known as fully developed sees so when speed the wind must be moving
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faster than the wave crest for energy energy transfer to continue to these are the wave wave development factors the wind speed must be faster than the way but he did you transfer to continue winter rain went for a short time will not generate large waves wind for a long time however will generate that is the runner-up to distance over which the wind blows without changing directions so if the wind is blowing straight line over a
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great distance as a long fetch of winning that more likely to develop larger ways so this concept that he fully developed see is the maximum wave height theoretically possible for he wind at a specific strength during a strong wind must blow continuously in one direction for nearly three days or void about cease to cover longer exposure will not increase the way by the wave energy is lost the breaking wave talks of his idea fully developed sees the biggest when wait you can have a type of win
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function again the wind blowing across a stretch of ocean for specific period of time typically takes three days to form so the fetch of the an interrupted distance over which the wind blows without significant change directions that interrupted distance this is the best away from the weather wind blowing all the way to words no longer increases with increased weight when speed passenger went along the way increased duration of when the longer it blows and the fest the link
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distance that is that the wind blows a strong wind must be continuously in one direction for nearly three days for the largest winning ways develop and develops these martyrs well move faster so this is an interesting look at a friends house waves moved to the open ocean waves separation or dispersion is a function of wavelength waves with the longest wavelength moved the fastest and leave the area of wave formation sooner so longer wavelengths waves will move away
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area more quickly this movie undulation ocean water caused by wave dispersion is called swell so I here to love wave waves travel in groups called wave trains so one through five 126 127 went through what does your wave trains ok as the leading wave of the group travels forward and transfer half of the energy for to initiate motion and the underserved service so as the leading wave moves along it transfers energy for causes a way ahead of the leading way
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into weight training can usually disappears while neway continuously form back of the train in this case we have 5678 is to weight train travels at about half the speed of any individual way so that speed of the wave train is no group velocity so how do waves behaving different water go again if you take the wavelength by two that is the death in which wave motion or or so there's no perceptible motion underneath his death so had the way he moves into shower child or water
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begin to lose that death and starts to impact the behavior of the way so ok waves and how they act end on the relationship between the wavelength in the water death wavelength determines of the ordinance but water gas determined so how big these words are a function of the wavelength of the longer wavelengths much larger or they are nearly circular in open water but once they get into depth at half their way bring those mortgage begin to fly now so Wade cannot feel the bottom
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Indies these waves are not feeling the bottom until the water is how the whaling so how to hear the Deepwater they don't get into shallow water when the water depth gauge how the way bring your kids are flattened out and they become traditional way when the water is less than 1 2002 waiving it's considered a shallower way that's typically we start to see these breaking in general the longer the whaling the faster the wave energy boost the water as water
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depth decreases away and begin to heal the bottom and then the waves speeds slow what ended up happening is because the wave speed slows as these waves here till the bottom the wavering between the way also short the way of the protein shore so deep water wave speed is proportional to the wavelength shallow water wave speed is important to the death again the speed of these deep water waves has to do with the wavelength defeated the shallow water waves has to do with the water
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way . did not change his water dead changes so wavelengths shorter waves bunch of death increases go deep water waves changed the shallow water these are the events that lead to wave to break first the way he loves the bottom of the water depths less than one-half the way of Lake second the circular motion of the water molecules in a way waypoint decreases the period remains the same that was previously the period the number of weight press passes remains the same with the wavelength
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decreases whereas become too high for the way of Kapolei becomes too high and the crest will move ahead supporting days in a way to break in here that graphically illustrated this world feels the bottom windy water shower after wave after wave length and weight begin to heal the way press becomes peace because the waves interviews tap into less water pushes it up it becomes p orbitals become more elliptical constrain constraining circular wave motion by
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interaction with the ocean floor US loans the wave it slows down while don't wait behind it became the original speed therefore the way Lancaster short distance between the way become shorter like when you're standing in the surf sound waves are closer together than they are out in the open ocean the period means change the number of ways to pass the time between the short for the whale approaches the critical 127 ratio of wave heights wavelength when it
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passes that ratio the top away literally can use moving faster than the bottom of way to 15 the way in breaks in the ratio of way by water depth is about three to four the movement of water particles as shown in red here no change in deepwater way to transition away stage shallow waters so here it is circle here in elliptical and hear the water literally moving back and forth after that water breaks in business
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deserves so two different types of ways waves of the typically see your Florida are spilling wave just over one another and then we have planting way way this page and create the two service calls so finding waves will break by only against the shore leaving erica Hill to the to talk about or channel between the crest of the wave while you wait for one when waves approach ashore in steeply sloped so essentially be plenty wave is so if this is a growing and this is the bottom
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and the way it comes in like this even if its steeply sloped the way of top the way that's thrown out of the bottle label literally stops and you give them plenty we're not the greatest coach in the world did you get that plunging way that's the to pay if you have a shallow flow at a more gradual slope more gradual slope like this then those waves crashed and now just sort of tumble down and that's kind of what we see here in Florida weather with a wave it doesn't
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plunging just sort of spills over so spilling waves occur up gradually sloping ocean bottom the crest of the spilling way slides down to face the way that the brakes on sure alright where where would you typically find the biggest way he did fine we had the highest winds and you had the highest winds were you have the mid latitude westerlies moving across the Pacific and the Atlantic Ocean and then very specifically the wesley is moving on
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process southern pacific the southern Indian Ocean and even to let's review the southern Atlantic Ocean to get these southern oceans the winds are not impeded by land is a lot of open ocean the wind only slightly by land here not impeded by land and sea your highest winds across this sex in the the Southern Ocean and that section of the Southern Ocean where you do see those those wave height up to five to six metres so much the highest waves
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occur in the Southern Ocean with the waves and more than 6 meters 20 feet are so high the lowest waves are found in the tropics remember the tropics for where we have the doldrums these are the men were not much happens is not a whole lot of wind and therefore there's not a whole lot of waves what happens when waves from different storm systems exist simultaneously city but the open ocean you might have wind coming from the northern Atlantic Ocean maybe someone
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coming from a tropical system down closer to the Caribbean and all the different winds will likely generate different types of of wind waves so what happens when different waves and storm systems interact well when they meet the interview with one another and his two types of interventions destructive and constructive into destructive interference is when two ways they actually cancel each other out resulting in a reduced or no way but also to waste coming each other two different directions
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really service Council themselves out more often we see constructive interference with their attitude interferences with a way to actually add to each other that results in waves are larger than the original ways but it's gonna be a combination of both pain how about angles the winds and waves meet at so what you get is this this offset a lot of different sides waves moving at the same region and then cycle of larger and smaller waves that we here in the
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breaking serve as what's known as the surf beach to surf beach next attack if you do but it's actually a scientific term referring to the cycle of a set of large breaking waves followed by a low and ascertain and smaller break now if you have a lot to construct a chance you get these freak waves that that occur to become gigantic and those are rogue waves and that is when you get in the way of a good price is higher than the maximum of
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those waves and humanely see that again now so constructive interference and he started their careers to over lapping waves of different wavelengths are shown one blue and one green if both are presented the oceans same time to interview with each other to form a composite way so by the way is actually the one that's gonna be in green YouTube waves and ready to the different ways and essentially given wavelength so there are periods of time when they're
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singing together and had constructive waves and period of time with their new park and you create destructive interference ICI additives situations here and the destructive situations here at the position of mine 12 waves work constructively interfere with each other to form large crescent trust and then it'd be an additional 12 the two waves of destructively interfere the question will be much smaller so that's the result of both constructive and
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destructive interference so you'll see level trace at this oil platform in the North Sea back in 1985 were constructive interference is responsible for a wave of almost 90 meters were talking 55 to 60 feet and you can see yet critical surf beach was constructed in destructive interference somewhere in between and then some constructive interference greatest rivers tremendous speed of this way and that's what the roadways three things that happened to
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waves particularly as they approached the shore refraction diffraction and reflects a wave refraction the slowing and bending of waves in shallow water labor factions occurs because waves usually approached shore angle the part of the wave line closer to the shore slows down as it could feel the bottom part of the way of further help moves faster so it catches up to impacted our way of wine the shallow water and that causes the way it did in order to refract did fracture in his win away
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literally propagates around an obstacle essentially for the same reason great wave hits and optical at the center of the wayward hit the optical the water shower in the way of delivering been around diffraction and you want to see reflections went away thousands back from an obstacle that encounters reflected waves can cause interference with oncoming lanes and create anyways think about the last time you at the ocean when the wave rolled up his
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teacher then rolled back out some time to create a little standing wave of interest to a water that is interference creating that standing way so this is what that looks like the way the progression is coming in this angle so this is the shoreline down here and this is the angle nice let's say this is a short facing east and north wind like that North East went swell is wave propagates along and the same speed again once the way begins to feel the
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bottom where it is the depth is half the whaling not then the wavelength begin to shorten a wave starts to slow down but these waves of moving the same speed and it literally causes these waves to bend and also causes and essentially come in almost straight parallel to the coastline so that we typically see at the beach as well as waves coming straight ahead because they felt the bottom they will begin to bend and straighten out and so where you give
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waves coming in a sharp angle to the beach is where the way of water depth is deep and then become solid very abruptly here on in the Atlantic Ocean in the east coast of Florida ocean bonds gradually slopes out and see how this enough times these waves of literally roof rack and then coming straight to short but this is refraction the Waterkeeper here its caliber work shower with a wave of slowly and a wavelength decreases his way of thinking the same
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way was moving more quickly and causes the way to bend to refract as it approaches sure you can see that refreshing as it comes along the shoreline hear the waves coming in this is the angle to moving and as they come along the shoreline neighbor Frank and then into the shoreline where in most cases are almost coming in parallel to the shore in every location so a refreshing in a way to coming in at this angle here and they were fracking bend
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in the coming almost straight into the ocean and in here is that that direction wind waves coming in straight year as a hit as long island it showered always begin to slow down and it's a date they'd end around just like the world was just straight coastline and then over here you get this constructive and destructive interference so where do fraction as an island chain on the navigators he's fraction patterns since the presence of violence out of sight on the horizon so if you are coming along
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this way you see this island you would get his constructive interference you know that somewhere off the distance there was silence so that is going to be your beef rationed you refresh and then again you also have the the reflect so storm surge is an abrupt bulge of water so it's kinda way but it's a bulge of Honor driven on shore by tropical cyclone hurricane or from a store so it's created by sustained onshore wind storm motion win motion his industry
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offshore onshore in Italy literally pushes amount of water out there was a time when we got to the low pressure of the hurricane they have lifted up and down but we now know that pressure driven soared start 65 percent the total all the rest of his wind blowing out water causing a pileup strong onshore winds have a component storm surges they caused went to pile up ahead of the driving way they can be very short lived but they can be up 2007 @ meters were
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talking twenty to twenty-five feet and raise the level of the ocean so this mount is almost like i coming in and raising the level of the ocean because the breaking waves caused by this win literally break on top of the storm search so storm surge consists of only a crossed so they really can't be assigned a wavelength for a period not like all the way of either but deadly brings the water causes damage as a matter of fact most of the damage from hurricanes and death
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hurricanes is caused by the storm search standing waves water rocking back and forth at a specific frequency in a confined area is called the cease and also get a standing wave and rivers where the water is moving along and for some reason he gets distracted off an obstacle and get off at school and moved back down you can also get a standing wave in a situation where the ocean wave moving up the seashore so try and draw a couple days for you if this is your
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seashore and your new wave is moving up it and they get to a point where it stops and goes back down this motion back down created standing wave right here where there's water in and is what emotion and you get the standing wave you can also get that in a river situation with the rivers flowing along like this but possible maybe there's a boulder here cause water to bounce back off and again you get that standing wave of one spot so that's what standing
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waves are but we also have these the standing wave that happen in closed basins and made it is a lake or a tidal basin but it's gonna be in closed basin and water cannot possibly back and forth in this closed basin and essentially is a standing wave of the water goes up and down up and down so water rocking back and forth at a specific frequency in confined areas called the CCC is also known has a standing wave away but oscillator vertically with no forward movement is not the way to do for you
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they go up and down but they have no for movement the note is that position of a standing wave water actually move sideways did not rise or fall so this is a standing wave going through a whole sequence from 1250 back tattoo against Texas is up and down up and down motion but no back and forth motion so wire can rock back and forth and it can find nation and and this happens sometimes in the great lakes where one side of the great lakes you have high water and the
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other side the Great Lakes you have very low water and so that's an example of that standing wave the Great Lakes represents gaming basin but wind blowing over that great lake for a longer time can create a waiver water pushes to one side and tsunamis and seismic Seaways tsunamis are very very long way blank shallow water shower because the way they get some on there since they always in shallow water pollution they're progressive waves caused by the rapid
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displacement of ocean waters tsunamis are essentially created by the vertical movement of earth along boss called seismic sea waves so this is this is your estimation that the service and is a fault them on Etsy bar right here and the pressure of that fall is pushing this part of the rock up and this part of the rock down maybe it's a convertible boundary so over many many many many thousands of years just pressure built up pressure built up and
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Sunday one day this law gets forced up in this sea bottom actually gets pushed us to look something like this displaces all this water and all that water gets pushed that displacement of water causes you should not be your initial tsunami before and then propagate away now they will also back up smaller waves in the majors not easy to move in that direction so I signed the waiver tsunamis generated with a vertical movement of earth along faults and they are seismic sea waves tsunamis
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Rochelle waterways because they're extremely long wavy lines and you get off it is not generated by a landslide so a lot of Earth coming down into the ocean iceberg calving overnight prozor party I see they fall off into the water call cabin so I strokes find replacers volcanic eruptions asteroid impacts any direct displacement of water will cause a tsunami and they are devastating much like storm surge they create the death a tribute to occasionally most recently we
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had the Indian Ocean tsunami earthquake back in December 2004 and it was exactly the situation should we had a convergent plate boundary where the displaced was moving up into this plane and once it was forced under it here and here's the fall it push this land up and agreed that that ocean wave now the main wave moved away but also the move toward toward land so it happened just offshore Jakarta and so this wave washed up the car to creating a tsunami there's a
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great Indian Ocean tsunami 26 December 2004 began when a rupture along a plate junction lifted the sea surface about 10 metres rather be so so the first inhabited to see it gets lifted up so that's the disturbing force what's the restraining their store and porous properties restoring force so it pulls it down but it is necessary to put it back under sea level gravity pull it further down and Cee Lo and so they needed to be restored backup
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and we're happy on C level back down back up in the background that's how this displays the water Creek Way gravity pulled the crackdown overshooting sea level and creating a truck the oscillating ocean forcing progressive way that radiated from the epicenter all directions the wave moved outward at this is a stocking for her and 72 miles per hour at El quickly move your body tremendously long wavelength at this theater about 50 minutes to reach
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Sumatra and I 28 minutes to get across the Indian Ocean to this is a very classic scenario a tsunami same thing happened in Haiti with offshore earthquake causing displacement of the ocean and a tsunami radiated away from that area because we have extremely long wavelengths they're always and shall always behave shallow water waves this anomaly is always in contact with the ocean floor and sometimes the taxi guided and refracted by seaport
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Apocrypha so the state of the tsunami can be calculated using the same formula as for other shallow water waves which that speed is the square root of gravity times death so she is worried grabbing the doubt the average speed about 470 miles per hour so you gravity is 9.8 m/s squared and the depth of the Pacific is about 4,600 metres so you multiply those two things together and take the square root and you get that average speed of the tsunami of 212 m/s work four hundred
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and seventy miles per hour so here is the way pipe again from the tsunami that happened yesterday that happened just off Japan with the disaster with the nuclear power plant and its not yet rated it radiated away from it because of that earthquake so that's the band that sticks and that's what it looked like to travel times how long to get occasionally that shallow water wave it's not too late to reach even as far south and east and the south coast of
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South America took just under a day so that wrapped up chapter 9 waves transmit energy not water so waves move energy epoxy ocean water does not move across the ocean surface and the speed of ocean waves usually depends on the whaling that we showed you that formula back here with the speed of the ocean wave is really a function of the depths of the ocean deep in the ocean to pass through the ocean waves and because the square root of
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gravity which is a fixed thing 9.8 m/s squared get 18 years for second kind of the debt and so as the DEP get lower and lower and lower shower and shower to speed up the way is going to get slower and slower speed of ocean waves usually depends on the wavelength with long waves moving fastest way to the fastest and waves moving in deeper water moving fast as arranged from short to long wavelengths and therefore generated by small services capillary waves by wind
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wind also wind waves the rocking of water and an enclosed space creates issues seismic and volcanic activity or other such displacement of water creates anomalies and in the way that we talk about next time so the behavior of course the disturbing force word tide is going to be the gravitational attraction between the Sun and Moon behavior waves depends largely on the relation between a wave signs and the depth of the water which is moving waves can be refracted
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or reflected they can break and they can interfere with one another they can also be defrocked around up when Wade can be waterways of the water and more than half their Wavelink deep and the waves a very long way of things are always in shallow water such as tsunamis are always in shallow water and these long way to travel very high speeds with great destructive power that will wrap up chapter nine again next week to take a look at what happens with high the bravery unique aspects cuts
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