In the recent major earthquake in japan why were the tsunamis so small?
955167
Because the underground didn't shift as drastically as it did in the big one.
387651
Tsunamis fall into a wave physics category called long waves, also known as shallow water waves.  This type of wave is characterized by a wavelength that is much larger than the water depth.  In the case of tsunamis, their wavelength might be 500 km versus, for example, a 4 km ocean depth, so even though 4 km is "deep", the waves are technically "shallow water waves".\n\nAccording to the sources I have included below, the velocity of shallow water waves does in fact vary according to the water depth.  According to the NOAA site, "The speed of a shallow-water wave is equal to the square root of the product of the acceleration of gravity (32ft/sec/sec or 980cm/sec/sec) and the depth of the water."  Therefore, the longer the wavelength, the faster the wave.  Since tsunamis have very large wavelengths, their speed is large.\n\nThe ripples on a pond that we're all so familiar with are technically short waves, or deep water waves, because the wavelength of the waves is not substantially larger than the depth of the water.  In this situation, the wave velocity is relatively constant for the wavelengths we typically see on the surface of a pond or bathtub, but according to the sources below, the wave speed does in fact vary according to the wavelength of the waves.\n\nYou are correct that the speed of a wave is constant in a given medium.  However, as you suspected after you lost the bet, tsunamis and ripples are effectively traveling through different media because of the ratio of their wavelengths to the water depth.
500590
Tsunamis are unlike wind-generated waves, which many of us may have observed on a local lake or at a coastal beach, in that they are characterized as shallow-water waves, with long periods and wave lengths. The wind-generated swell one sees at a California beach, for example, spawned by a storm out in the Pacific and rhythmically rolling in, one wave after another, might have a period of about 10 seconds and a wave length of 150 m. A tsunami, on the other hand, can have a wavelength in excess of 100 km and period on the order of one hour. \nAs a result of their long wave lengths, tsunamis behave as shallow-water waves. A wave becomes a shallow-water wave when the ratio between the water depth and its wave length gets very small. Shallow-water waves move at a speed that is equal to the square root of the product of the acceleration of gravity (9.8 m/s/s) and the water depth - let's see what this implies: In the Pacific Ocean, where the typical water depth is about 4000 m, a tsunami travels at about 200 m/s, or over 700 km/hr. Because the rate at which a wave loses its energy is inversely related to its wave length, tsunamis not only propagate at high speeds, they can also travel great, transoceanic distances with limited energy losses.
873581
Can, do and will get worse.\n\nFrom  Nunatsiaq News:\n\n"In the last century, three of the 10 largest earthquakes in the world have occurred in Alaska, and these produced deadly tsunamis. In 1958, a landslide caused by an earthquake sent a tsunami 524 metres high into Lihuya Bay, killing several fishermen and stripping the fiord of vegetation.\n\nThe presence of sea ice has lessened or "dampened" the impacts of most tsunamis in the Arctic Ocean. That's why Alan W. Harris, a senior research scientist at the Space Science Institute in California, maintains there's little possibility of a killer wave doing much damage in the Arctic and "only polar bears need worry about whether the ice damps the tsunami wave from an Arctic impact."\n\nBut in the future, with increased calving of glaciers and ice shelves, where massive hunks of ice break off and crash down into the water, there could be more Arctic tsunami-type waves, and, with less sea ice, these could have a larger, visible impact."
376357
there are many earthquake observatories in japan.\n we can get almost correct information within 10minutes\n but sometimes we cannot count on the machines.earthquakes\n occur everyday.
856700
The tectonic plates were already broken before oil was drilled, it has always been that way since the earth cooled. Oil drilling is not the reason earthquakes exist.
7842
a tsunami is caused by an earthquake deep in the ocean, and a hurricane is like a big tornato, thus meaning when hot and cold air meet, they swirl over the ocean and make a hurricane. \nhope i was of help!\nHappy Holidays, -creaive:)
557950
tsunami is mainly caused by the fault caused in the interior of the earth in the sea bed, coz of which the water gets charged up! its sumthing like whn we put sumthing in the glass of water & the water forms ripples!this is in a glass of water, imagine,in the ocean or sea full of water! one ripple causes many to go ahead! this is how tsunami takes place! first effect, the level of water rises & captures the land & the shore where it strikes is all together devastated,eg. nagapattinam coast! second, once a tsunami is caused, it will take place in other forms all over the world. coz the land displaced in the sea bed will have to get a flat shape..till thn itll cause other floors of earth to get displaced as wel1! its an ongoin phenomena, sumtimes itll take shape into destruction, other times it will not! we can just monitor thm , but cannot stop thm coz its nature after all! nobody can control thm!
67084
By definition, a hurricane is fierce rotating storm with an intense centre of low pressure that only happens in the tropics. In south-east Asia they're known as typhoons and in the Indian Ocean, cyclones.\nThey cause high winds, huge waves, and heavy flooding. One of the most powerful of all weather systems, hurricanes are powered by the heat energy released by the condensation of water vapour. However, the conditions have to be exact for a hurricane to form, with the sea's surface temperature being above 26.5°C.\n\nStorm surge\nThis is caused by the intense low pressure at the eye of a hurricane, combining with the effect of strong winds. The sea rises 1cm for every millibar of pressure - if the pressure is 930 millibar, the sea surge will be about 80 cm. Hurricanes can raise the seas surface by as much as 4m.\n\nThe hurricane winds push the surge along in front of its path. When this surge hits low-lying coasts, the effects can be devastating. In addition to the sea surge, flooding can also result from torrential rain falling from the storm clouds.\n\nTsunamis\nA tsunami (pronounced tsoo-nah-mee) is a chain of fast moving waves caused by sudden trauma in the ocean. They can be generated by earthquakes, volcanic eruptions, or even the impact of meteorites. Tsunami are also incorrectly known as tidal waves, but unlike tidal waves they are not caused by changes in the tides.\n\nThey are most common around the edge of the Pacific, where more than half of the world's volcanoes are found. These seismic surges can assault coastlines, often with little or no warning. Rocks weighing as much as 20 metric tonnes have been plucked from sea walls and carried 180m inland. \n\nWave power\nTsunamis aren't like wind-generated waves that rhythmically roll onto a beach. A tsunami can have a wavelength (ie distance between wave crests) in excess of 100km (60 miles) and there may be an hour between them. They travel at great speeds across an ocean with hardly any energy losses and are barely noticeable out at sea.\n\nOver the deep Pacific Ocean, a tsunami travels at about 800kph (500mph). If an earthquake happened in Los Angeles, a tsunami could hit Tokyo quicker than you could fly between the cities by jet. The tsunami caused by the earthquake off the coast of Indonesia in late 2004 travelled 4,500km (2,800 miles) to Somalia in East Africa in just seven hours.\n\nAs a tsunami leaves the deep water of the open ocean and travels into the shallower water near the coast, it behaves like a normal wave - only with more muscle.\n\nShallow water slows the tsunami and its height grows. Tsunamis batter the coast with tremendous amounts of energy. They can strip sand from beaches, tearing up trees, and even obliterating whole towns. Some have been known to reach as much as 30m above sea level. \n\n\nThe only way they may be alike is that because of a Hurricane, you might have huge waves, but still, waves generated by Tsunami would be larger.
204545
I'm assuming you're asking about tectonic plate movement and not heavier stuff like the earth tilting on its axis. The first link shows a map of the earth currently and how it's moving so you can figure it out on your own.  The second link gives your the answer to your question.  It shows the Pacific Ocean getting much narrower.
946669
Earthquakes 10.5 are impossibly big.  Places in America where you get earthquakes as big as 9 only happen along the coast of Alaska.  The biggest earthquake that can happen on the San Andreas is about 8.  Volcanoes in the US are only related to some faults, not all, and they are not interconnected, so one eruption is not related to nor does it cause another.\n\nHere are some basics on earthquakes/volcanism to help you with why this is physically impossible:\n\nEarthquakes: \nIt all comes down to stress and strain from the interaction of different plates, chiefly at the boundaries. It is not 'the plates rubbing together' as many people say; or at least that's a very simplistic view.\n\nPlate tectonics causes stress on the continents and oceans, all over the surface of the earth. In some places, the stress is very small (usually within the plates). Elsewhere, the stress is high, usually where the plates meet each other. Since each plate moves, when two come in contact, the stress each other. They can push on each other and cause compressional stress, they can pull with extensional stress, and they can slide past or shear each other with tensional stress.\n\nFaulting, causing earthquakes, comes from the fact that this stress is building up all the time, but rocks and continents are strong materials. Just like hitting a rock with a small hammer, you do put stress on it, but a small amount. It would take a sledgehammer to put enough strain (effects and accumulation of stress) to build up and cause breakage. In the earth, the area around an active fault builds up strain from the stress of plate tectonics. Most faults become locked, because of this strength, and thus can not release their strain. Away from the fault, the stress produces very small and slow movement of the rock masses as a whole. Eventually, the strain is too much and the rest of the plate has moved too far and the fault releases the strain build-up all at once in a big stress release called an earthquake. This is called the elastic rebound theory, and it explains most (but not all) movements.\n\nThis is why an earthquake's size is relative to the fault size. The bigger the fault, the bigger the strain build up, and the bigger the release in an earthquake. Subduction zones and collision zones, where large portions of plates actually can rub together as a whole, have the really big earthquakes, like the 2004 Sumatra earthquake. In other plate boundaries, the entire plate boundary does not act together, so the faults become spread out and many faults take up the strain from the tectonic stress, like with the San Andreas Fault in California (it only takes up ~3/4 of the stress between the plates).\n\nEarthquakes are really tricky things; there is still so much we need to learn. As of now, there is no way to predict them, but we can say where the danger is highest and about how long between events.\n\nVolcanoes:\nThere are several processes in Plate Tectonics that cause volcanism, but they result in two main types of volcanism.\n\nVolcanism in subduction is caused by volitals, like H2O, CO2. These are carried down by the plate, mainly in the form of weak minerals. These minerals break down with pressure and temperature into stronger minerals that don't contain water and carbon dioxide. The leftover gases and liquids travel into the mantle (the mantle wedge) and hydrate the mantle, causing melting. The melt rises and then... volcano!\n\nThe other main cause is from rising mantle material, which forms decompression melting. Basically, hot mantle is kept from melting by the pressure of the earth at depth. When this material rises, the pressure drops much faster than the temperature, and thus it partially melts. This mainly occurs at divergent boundaries and hot spots, which are areas in plate tectonics that have rising materials or spreading.
451814
The 2004 Indian Ocean earthquake, which had a magnitude of 9.15, triggered a series of lethal tsunamis on  December 26, 2004 that killed approximately 230,000 people (including 168,000 in Indonesia alone), making it the deadliest tsunami in recorded history.[7] The tsunami killed people over an area ranging from the immediate vicinity of the quake in Indonesia, Thailand and the north-western coast of Malaysia to thousands of kilometres away in Bangladesh, India, Sri Lanka, the Maldives, and even as far as Somalia, Kenya and Tanzania in eastern Africa. The disaster prompted a huge worldwide effort to help victims of the tragedy, with billions of dollars being raised for disaster relief.\n\nUnlike in the Pacific Ocean, there was no organized alert service covering the Indian Ocean. This was in part due to the absence of major tsunami events between 1883 (the Krakatoa eruption, which killed 36,000 people) and 2004. In light of the 2004 Indian Ocean tsunami, UNESCO and other world bodies have called for a global tsunami monitoring system.
324754
http://www.ga.gov.au/urban/factsheets/tsunami4.jsp\n\nA tsunami is recorded on Australia's coastline about once every two years. However, most are very small and classified low risk. However, several large tsunamis have hit Australia's north-west coast. This area is classified moderate risk, due to its proximity to Indonesia and other countries where large earthquakes and volcanic eruptions can occur, so this region has a moderate tsunami risk.\nThe huge 1883 volcanic eruption of Krakatau in Indonesia produced tsunamis up to 40 metres high. These tsunamis killed 36,000 people, carried boats three kilometres inland and moved 100 tonne blocks of reef limestone. The tsunamis travelled across the Pacific and Indian Oceans and caused a six metre tsunami on the north west coast of Australia.\nIn the last 1000 years the Australian coast may have experienced large tsunamis because shells, coral and large boulders have been found 20-30 metres above sea level and several kilometres inland. On 22 August 2003 a huge earthquake occurred just off the south-west coast of New Zealand, 2500 kilometres from Australia's east coast. Fortunately this event only caused a small local tsunami less than a metre high.
565481
Because the primary 'earthquake' is measurable by a physical realignment of two or more techtonic plates in a specific direction. 'aftershocks' are incremental settlements of these plates, and are not necessarily in he same direction.  Hope that helps!
573798
Obviously it was one of the greatest and more damaging natural dis tasters in modern history. It decimated local populations and devastated local industries such as tourism, fishing, etc. You can do a Yahoo! search for "Tsunami video" and you will get a physical look at what it actually looked liked coming in from the sea.
962089
No.Tsunamis occur usally after there is an earthquake of a 7.0 maginitude under the ocean, for most tsunamis to occur the fault or the earthquake has to be under water and has to go up a reasonable mount of feet. Then it sends a wave which passes through a boey system and then that notifiys a the people on land.\nSince earthquakes are impossible to predict Tsunamis are too and that points also how often they occur. Not all earthquakes cause tsunamis, and if you heard of land one, it is most probaly it caused a underwater land slide or an out of water land slide which then crashes into the sea depending how big it is it will make anything to 1,000 foot wave.
731200
Very pertinent.  If you live on the Pacific Ocean, you can check the two tsunami information web sites below.  Besides current warnings they have lots of information on tsunami and earthquakes in general.  That said, tsunami prediction is very imprecise.  In my town, Crescent City, California, we had a tsunami last week as a result of the earthquake north of Japan.  The prediction center had issued an "all clear", then later rescinded it.  At the predicted time, a small wave of only a few inches occurred, but two hours later a six foot wave caused nearly one million dollars damage to the harbor.\n\nA major problem with tsunami prediction is that many big waves are caused by underwater landslides, events that may not require a large quake to happen.  Additionally, local factors can have a great effect, increasing or decreasing the size of waves.\n\nIf you are in a tsunami zone and you feel the earth move, IMMEDIATELY move to the highest ground possible, preferably on foot as often roads become clogged.  Even if a quake is close at hand you may have several minutes to get away.  Often people have hours to prepare, and after our experience the other day I will always just assume the worst.  The Tsunami Warning Center is on my "favorites" list in my browser, but after the events of last week my faith has been shaken.