Tsunami

Source: NOAA National Weather Service Forecast Office. (*) Duration of central eclipse.. Possible Tsunamis. Selected past and upcoming eclipses are:. Other tsunamis that have occurred include the following:. Eclipses where the path of totality crosses major population centres generate the most interest in the general public. In light of the 2004 Indian Ocean tsunami, UNESCO and other world bodies have called for a global tsunami monitoring system. Although there is a total eclipse visible somewhere on Earth most years, some are more conveniently observed than others.

This is in part due to the absence of major tsunami events between 1883 (the Krakatoa eruption, which killed 36,000 people) and 2004. [1].
Unlike in the Pacific Ocean, there is no organized alert service covering the Indian Ocean. Like a transit of a planet it will not get dark.
. The satellite passes over the face of the Sun in about a second, typically.
. This means the best you can get is a satellite transit, but these events are difficult to watch, because the zone of visibility is very small.

The disaster prompted a huge worldwide effort to help victims of the tragedy, with billions of dollars being raised for disaster relief. At the altitude of the International Space Station, for example, an object would need to be about 3.35 km across to blot the Sun out entirely. 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. But none are large enough to cause an eclipse. 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 275,000 people (more than 168,000 in Indonesia alone), making it the deadliest tsunami in recorded history. Artificial satellites can also get in the line between Earth and Sun. As a result, 202 people on the small island of Okushiri lost their lives, and hundreds more were missing or injured. When no such planet was found during such an eclipse, the possibility of its existence was ruled out.

A devastating tsunami occurred off the coast of Hokkaido in Japan as a result of an earthquake on July 12, 1993. At one time, some scientists — including Albert Einstein — hypothesized that there may have been a planet even closer to the Sun than Mercury; the only way to confirm its existence would have been to observe it during a total solar eclipse. The total number of victims of this tragedy was 259 dead, 798 wounded and 95 missing presumed dead. More common — but still quite rare — is a conjunction of any planet (not confined exclusively to Mercury or Venus) at the time a total solar eclipse, in which event the planet will be visible very near the eclipsed Sun, when without the eclipse it would have been lost in the Sun's glare. When the Tumaco Tsunami hit the coast, it caused great destruction in the city of Tumaco, as well as in the small towns of El Charco, San Juan, Mosquera and Salahonda on the Pacific Coast of Colombia. This was the lowest time difference between a transit of a planet and a solar eclipse in the historical past. The earthquake was felt in Bogotá, Cali, Popayán, Buenaventura and several other cities and towns in Colombia and in Guayaquil, Esmeraldas, Quito and other parts of Ecuador. Only 5 hours after the transit of Venus on June 4, 1769 there was a total solar eclipse, which was visible in Northern America, Europe and Northern Asia as partial solar eclipse.

The earthquake and the resulting tsunami caused the destruction of at least six fishing villages and the death of hundreds of people in the Colombian province of Nariño. The next anticipated simultaneous occurrence of a Solar eclipse and a transit of Mercury will be on July 5, 6757, and of a Solar eclipse and a transit of Venus is expected on April 5, 15232. A magnitude 7.9 earthquake occurred on December 12, 1979 at 7:59:4.3 (UTC) along the Pacific coast of Colombia and Ecuador. But these events are extremely rare because of their short durations. The tsunamis were up to 6 m tall, and killed 11 people as far away as Crescent City, California. In principle, the simultaneous occurrence of a Solar eclipse and a transit of a planet is possible. After the magnitude 9.2 Good Friday Earthquake, tsunamis struck Alaska, British Columbia, California and coastal Pacific Northwest towns, killing 121 people. On these occasions, an object — especially a planet (often Mercury) — may be visible near the sunrise or sunset point of the horizon when it could not have been seen without the eclipse.

Nearly 2,000 people were killed. When this occurs shortly before the former or after the latter, the sky will appear much darker than it would otherwise be immediately before sunrise or after sunset. A tsunami was triggered which swept over the top of the dam (without bursting it) and into the valley below. It is possible for a solar eclipse to attain totality (or in the event of a partial eclipse, near totality) before sunrise or after sunset from a particular location. The reservoir behind the Vajont Dam in northern Italy was struck by an enormous landslide. During a partial eclipse, the light spots will show the partial shape of the sun, as seen on the picture. The number of people killed by the earthquake and subsequent tsunami is estimated to be between 490 and 2,290. These are images of the sun.

When the tsunami hit Onagawa, Japan, almost 22 hours after the quake, the wave height was 3 m above high tide. Normally the spots of light which fall through the small openings between the leaves of a tree, have a circular shape. 61 lives were lost allegedly due to people's failure to heed warning sirens. During a solar eclipse special observations can be done with the unaided eye. The highest wave at Hilo Bay was measured at around 10.7m (35 ft.). Note that the modern conventional dates are different by a year or two, and that these two eclipse records have been ignored so far. The first tsunami arrived at Hilo, Hawaii approximately 14.8 hrs after it originated off the coast of South Central Chile. The sky suddenly darkened in the middle of the sky, well after the battles of Thermopylae and Salamis, after the departure of Mardonius to Thessaly at the beginning of the spring of (477 BC) and his second attack on Athens, after the return of Cleombrotus to Sparta.

It spread across the entire Pacific Ocean, with waves measuring up to 25 metres high. Herodotus (book IX, 10, book VIII, 131, and book IX, 1) reports that another solar eclipse was observed in Sparta during the next year, on August 1, 477 BC. Its epicenter off the coast of South Central Chile, generated one of the most destructive tsunamis of the 20th century. An annular eclipse of the Sun occurred at Sardis on February 17, 478 BC, while Xerxes was departing for his expedition against Greece, as Herodotus, VII, 37 recorded ([Hind and Chambers, 1889: 323] considered this absolute date more than a century ago). The Great Chilean Earthquake, at magnitude 9.5 the strongest earthquake ever recorded. One likely candidate took place on May 28, 585 BC, probably near the Halys river in the middle of modern Turkey. Note: The Pacific Tsunami Warning Center was established to track these killer waves and provide warning. Exactly which eclipse was involved has remained uncertain, although the issue has been studied by hundreds of ancient and modern authorities.

The tsunami is locally known in Hawaii as the April Fools Day Tsunami in Hawaii due to people thinking the warnings were an April Fools prank. Soldiers on both sides put down their weapons and declared peace as a result of the eclipse. The Aleutian Island earthquake tsunami that killed 165 people on Hawaii and Alaska resulted in the creation of a tsunami warning system, established in 1949 for Pacific Ocean area countries. Herodotus wrote that Thales of Milete predicted an eclipse which occurred during a war between the Medians and the Lydians. The resulting tsunami measured over 7 metres in height and took about 2½ hours to reach the Burin Peninsula on the south coast of Newfoundland, where 28 people lost their lives in various communities. For a discussion, see the text by Stephenson. The quake was felt throughout the Atlantic Provinces of Canada and as far west as Ottawa, Ontario and as far south as Claymont, Delaware. There have been other claims to date earlier eclipses, in Babylon and also in China, but these are highly disputed and rely on much supposition.

On November 18, 1929, an earthquake of magnitude 7.2 occurred beneath the Laurentian Slope on the Grand Banks. This is the earliest solar eclipse that can be exactly dated. On the facing coasts of Java and Sumatra the sea flood went many miles inland and caused such vast loss of life that one area was never resettled but went back to the jungle and is now the Ujung Kulon nature reserve. A solar eclipse of 15 June 763 BC mentioned in an Assyrian text is important for the Chronology of the Ancient Orient. Tsunami waves were observed throughout the Indian Ocean, the Pacific Ocean, the American West Coast, South America, and even as far away as the English Channel. After a Saros cycle finishes, a new Saros cycle begins 1 Inex later (hence its name: in-ex). A series of large tsunami waves was generated from the explosion, some reaching a height of over 40 metres above sea level. The Inex cycle is itself a poor cycle, but it is very convenient in the classification of eclipse cycles.

The island volcano of Krakatoa in Indonesia exploded with devastating fury in 1883, blowing its underground magma chamber partly empty so that much overlying land and seabed collapsed into it. The Saros cycle is probably the most well known, and one of the best, eclipse cycles. The philosophical concept of the sublime, as described by philosopher Immanuel Kant in the Observations on the Feeling of the Beautiful and Sublime, took inspiration in part from attempts to comprehend the enormity of the Lisbon quake and tsunami. Two such cycles are the Saros and the Inex. Philosophers of the Enlightenment, notably Voltaire, wrote about the event. If the date and time of a solar eclipse is known, it is possible to predict other eclipses using eclipse cycles. Europeans of the 18th century struggled to understand the disaster within religious and rational belief systems. Normally this is not visible because the photosphere is much brighter than the corona.

Historical records of explorations by Vasco da Gama and other early navigators were lost, and countless buildings were destroyed (including most examples of Portugal's Manueline architecture). For astronomers, a total solar eclipse forms a rare opportunity to observe the corona (the outer layer of the Sun's atmosphere). The earthquake, tsunami, and subsequent fires killed more than a third of Lisbon's pre-quake population of 275,000. (eclipse predictions by Fred Espenak, NASA/GSFC.). Before the great wall of water hit the harbour, waters retreated, revealing lost cargo and forgotten shipwrecks. The longest total solar eclipse during the 8,000-year period from 3000 BC to 5000 AD will occur on July 16, 2186, when totality will last 7 min 29 s. Many townspeople fled to the waterfront, believing the area safe from fires and from falling debris from aftershocks. The next eclipse of comparable duration will not occur until June 25, 2150.

Tens of thousands of Portuguese who survived the great 1755 Lisbon earthquake were killed by a tsunami which followed a half hour later. Observers aboard a Concorde aircraft were able to stretch totality to about 74 minutes by flying along the path of the Moon's umbra. January 26 - The Cascadia Earthquake, one of the largest earthquakes on record, ruptures the Cascadia Subduction Zone offshore from Vancouver Island to northern California, creating a tsunami logged in Japan and oral traditions of the American First Nations. The last time this happened was June 30, 1973. In 2002 it was suggested that the Bristol Channel floods of 1607 in England and Wales, UK, may have been caused by a tsunami. During each millennium there are typically fewer than 10 total solar eclipses exceeding 7 minutes. Santorini is regarded as the most likely source for Plato's literary parable of Atlantis. Totality can never last more than 7 min 40 s, and is usually much shorter.

At some time between 1650 BC and 1600 BC (still debated), the volcanic Greek island Santorini erupted, causing a 100 m to 150 m high tsunami that devastated the north coast of Crete, 70 km (45 miles) away, and would certainly have wiped out the Minoan civilization along Crete's northern shore. Then, after waiting so long, the total eclipse only lasts for a few minutes, as the Moon's umbra moves eastward at over 1700 km/h. In the North Atlantic Ocean (Norwegian Sea), the Storegga Slides were a major series of sudden underwater land movements over the course of tens of thousands of years, which caused tsunamis and megatsunamis across a wide area. Although they occur somewhere on Earth approximately every 18 months, it has been estimated that they recur at any given place only once every 370 years, on average (Stephenson, p.54). Very small tsunamis, non-destructive and undetectable without specialized equipment, occur frequently as a result of minor earthquakes and other events. Total solar eclipses are rare events. Tsunamis occur most frequently in the Pacific Ocean, but are a global phenomenon; they are possible wherever large bodies of water are found, including inland lakes, where they can be caused by landslides. Outside of the central track, a partial eclipse can usually be seen over a much larger area of the Earth.

See also List of historic tsunamis by death toll.. In the most favourable circumstances, when a total eclipse occurs very close to perigee, the track can be over 250 km wide and the duration of totality may be over 7 minutes. While it would take some years for the trees to grow to a useful size, such plantations could offer a much cheaper and longer-lasting means of tsunami mitigation than the costly and environmentally destructive method of erecting artificial barriers. The width of the track of a central eclipse varies according to the relative apparent diameters of the Sun and Moon. [5] Environmentalists have suggested tree planting along stretches of sea coast which are prone to tsunami risks. The Earth is also rotating from west to east, but the umbra always moves faster than any given point on the Earth's surface, so it almost always appears to move in a roughly west-east direction across a map of the Earth (there are some rare exceptions to this which can occur during an eclipse of the midnight sun in arctic or antarctic regions). In one striking example, the village of Naluvedapathy in India's Tamil Nadu region suffered minimal damage and few deaths as the wave broke up on a forest of 80,244 trees planted along the shoreline in 2002 in a bid to enter the Guinness Book of Records. During a central eclipse, the Moon's umbra (or antumbra, in the case of an annular eclipse) moves rapidly from west to east across the Earth.

Some locations in the path of the 2004 Indian Ocean tsunami escaped almost unscathed as a result of the tsunami's energy being sapped by a belt of trees such as coconut palms and mangroves. However, some are visible only as partial eclipses, because the umbra passes either above or below the earth, and others are central only in remote regions of the arctic or antarctic. The effects of a tsunami can be mitigated by natural factors such as tree cover on the shoreline. This means that in any given year, there will always be at least two solar eclipses, and there can be as many as five. The wall may have succeeded in slowing down and moderating the height of the tsunami but it did not prevent major destruction and loss of life. Sometimes the New Moon occurs close enough to a node during two consecutive months. The port town of Aonae was completely surrounded by a tsunami wall, but the waves washed right over the wall and destroyed all the wood-framed structures in the area. Therefore, the New Moon occurs close to the nodes at two periods of the year approximately six months apart, and there will always be at least one solar eclipse during these periods.

For instance, the tsunami which hit the island of Hokkaido on July 12, 1993 created waves as much as 30m (100 ft) tall - as high as a 10-story building. The Moon's orbit intersects with the ecliptic at the two nodes that are 180 degrees apart. However, their effectiveness has been questioned, as tsunamis are often higher than the barriers. The time between one perigee and the next is known as the anomalistic month. Other localities have built floodgates and channels to redirect the water from incoming tsunamis. Finally, the Moon's perigee is moving forwards in its orbit, and makes a complete circuit in about 9 years. Japan has implemented an extensive programme of building tsunami walls of up to 4.5m (13.5 ft) high in front of populated coastal areas. This period is called the draconitic month.

While it is not possible to prevent a tsunami, in some particularly tsunami-prone countries some measures have been taken to reduce the damage caused on shore. This means that the time between each passage of the Moon through the ascending node is slightly shorter than the sidereal month. Some scientists speculate that animals may have an ability to sense subsonic Rayleigh waves from an earthquake minutes or hours before a tsunami strikes shore (Kenneally, [4]).. However, the nodes of the Moon's orbit are gradually moving in a retrograde motion, due the the action of the Sun's gravity on the Moon's motion, and they make a complete circuit every 18.5 years. The phenomenon was also noted in Sri Lanka in the 2004 Indian Ocean earthquake ([3]). The Moon crosses from south to north of the ecliptic at its ascending node. The Lisbon quake is the first documented case of such a phenomenon in Europe. This is known as the synodic month, and corresponds to what is commonly called the lunar month.

Many animals sense danger and flee to higher ground before the water arrives. This means that the average time between one New Moon and the next is longer, and is approximately 29.6 days. One of the early warnings comes from nearby animals. However, during one sidereal month, the Earth has moved on in its orbit around the Sun. Computer models can roughly predict tsunami arrival and impact based on information about the event that triggered it and the shape of the seafloor (bathymetry) and coastal land (topography).[2]. This is known as the sidereal month. In some communities on the west coast of the United States, which is prone to Pacific Ocean tsunamis, warning signs advise people where to run in the event of an incoming tsunami. The Moon orbits the Earth in approximately 27.3 days, relative to a fixed frame of reference.

Regions with a high risk of tsunamis may use tsunami warning systems to detect tsunamis and warn the general population before the wave reaches land. It is only when the Moon is closer to the Earth than average (near its perigee) that a total eclipse occurs. In a low-lying coastal area, a strong earthquake is a major warning sign that a tsunami may be produced. On average, the Moon appears to be slightly smaller than the Sun, so the majority (about 60%) of central eclipses are annular. Again, being educated about a tsunami is important, to realise that when the water level drops the first time, the danger is not yet over. This means that the apparent size of the Moon is sometimes larger or smaller than average, and it is this effect that leads to the difference between total and annular eclipses (the distance of the Earth from the Sun also varies during the year, but this is a smaller effect). In instances where the leading edge of the tsunami is its first peak, succeeding waves can lead to further flooding. The Moon's orbit is also elliptical, which means that the distance of the Moon from the Earth can vary by about 6% from its average value.

People unaware of the danger may remain at the shore due to curiosity, or for collecting fish from the exposed sea bed. A solar eclipse can occur only when the New Moon occurs close to one of the points (known as nodes) where the Moon's orbit crosses the ecliptic – hence the name. If the slope is shallow, this recession can exceed many hundreds of metres. Because of this, at the time of a New Moon, the Moon will usually pass above or below the Sun. In instances where the leading edge of the tsunami wave is its trough, the sea will recede from the coast half of the wave's period before the wave's arrival. The Moon's orbit around the Earth is inclined at an angle of just over 5 degrees to the plane of the Earth's orbit around the Sun (the ecliptic). Tsunamis cannot be prevented or precisely predicted, but there are some warning signs of an impending tsunami, and there are many systems being developed and in use to reduce the damage from tsunamis. The larger light gray area is the penumbra, in which a partial eclipse will be seen.

The following have at various times been associated with a tsunami [1]:. The small area where the umbra touches the Earth's surface is where a total eclipse will be seen. As a result, Hilo suffered worse damage than any other place in Hawaii, with the tsunami/seiche reaching a height of 14 m and killing 159 inhabitants. The dark gray region to the right of the moon is the umbra, where the Sun is completely obscured by the Moon. That meant that every second wave was in phase with the motion of Hilo Bay, creating a seiche in the bay. The diagram to the right shows the alignment of the Sun, Moon and Earth at a solar eclipse. The natural resonant period of Hilo Bay is about thirty minutes. For more information on safe eclipse viewing, see:.

For instance, the tsunami that hit Hawaii on April 1, 1946 had a fifteen-minute interval between wave fronts. Note that it is never safe to look at an annular or partial eclipse directly, because the Sun's disk is never completely covered during this type of eclipse. Local geographic peculiarities can lead to seiche or standing waves forming, which can amplify the onshore damage. The exact time and duration of totality for the location from which the eclipse is being observed should be determined from a reliable source (local astronomers, etc.). They also need not be symmetrical; tsunami waves may be much stronger in one direction than another, depending on the nature of the source and the surrounding geography. However, it is important to stop directly viewing the Sun promptly at the end of totality. However, tsunami waves can diffract around land masses (as shown in this Indian Ocean tsunami animation as the waves reach southern Sri Lanka and India). The Sun's faint corona will be visible, and even the chromosphere, solar prominences, and possibly even a solar flare may be seen.

Tsunamis propagate outward from their source, so coasts in the "shadow" of affected land masses are usually fairly safe. Contrary to popular belief, it is safe to observe the total phase of a total solar eclipse directly with the unaided eye, binoculars or a telescope, when the Sun's photosphere is completely covered by the Moon; indeed, this is a very spectacular and beautiful sight, and it is too dim to be seen through filters. There is no proof for this. These precautions apply to viewing the Sun at any time except during the totality phase of a total solar eclipse (see below). This gives the transient pressure built up during the quake as equal to twice and in addition to the hydrostatic pressure. The optical viewfinders provided with some video and digital cameras are not safe. The passing "hump" mentioned earlier is a "momentum flux" equal to density multiplied by the square of the velocity. Viewing the Sun's disk on a video display screen (provided by a video camera or digital camera) is safe, although the camera itself may be damaged by direct exposure to the Sun.

However a conjecture exists for velocities. However, care must be taken to ensure that no one looks through the projector (telescope, pinhole, etc.) directly. At a water depth of 40 m, the speed would be 20 m/s (about 72 km/h or 45 mi/h), which is much slower than the speed in the open ocean but the wave would still be difficult to outrun. The projected image of the Sun can then be safely viewed; this technique can be used to observe sunspots, as well as eclipses. For example, in the Pacific Ocean, where the typical water depth is about 4000 m, a tsunami travels at about 200 m/s (720 km/h or 450 mi/h) with little energy loss, even over long distances. This can be done by projecting an image of the disk onto a white piece of paper or card using a pair of binoculars (with one of the lenses covered), a telescope, or another piece of cardboard with a small hole in it (about 1 mm diameter), often called a pinhole camera. 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/s²) and the water depth. The safest way to view the Sun's disk is by indirect projection.

A wave becomes a 'shallow-water wave' when the ratio between the water depth and its wavelength gets very small, and since a tsunami has an extremely large wavelength (hundreds of kilometres), tsunamis act as a shallow-water wave even in deep oceanic water. Only properly designed and certified solar filters should ever be used for direct viewing of the Sun's disk. As a wave goes down the whip from handle to tip, the same energy is deposited in less and less material, which then moves more violently as it receives this energy. Sunglasses are not safe, since they do not block the harmful and invisible infrared radiation which causes retinal damage. The steepening process is analogous to the cracking of a tapered whip. The Sun's disk can be viewed using appropriate filtration to block the harmful part of the Sun's radiation. While a person at the surface of deep water would probably not even notice the tsunami, the wave can increase to a height of 30 m or more as it approaches the coastline and compresses. Viewing the Sun during partial and annular eclipses (and during total eclipses outside the brief period of totality) requires special eye protection, or indirect viewing methods.

As the wave approaches land, the sea shallows and the wave no longer travels as quickly, so it begins to 'pile-up'; the wave-front becomes steeper and taller, and there is less distance between crests. Viewing the Sun's disk through any kind of optical aid (binoculars, a telescope, or even an optical camera viewfinder) is even more hazardous, although just viewing it with the naked eye can easily cause damage. The wave travels across the ocean at speeds from 500 to 1,000 km/h. Unfortunately, looking at the Sun during an eclipse is just as dangerous as looking at it outside an eclipse, except during the brief period of totality, when the Sun's disk is completely covered (totality occurs only during a total eclipse and only very briefly—it does not occur during a partial or annular eclipse). The energy of a tsunami passes through the entire water column to the sea bed, unlike surface waves, which typically reach only down to a depth of 10 m or so. However, during an eclipse, with so much of the Sun covered, it is easier and more tempting to stare at it. This is often practically unnoticeable to people on ships. Under normal conditions, the Sun is so bright that it's difficult to stare at it directly, so there is no tendency to look at it in a way that might damage the eye.

The actual height of a tsunami wave in open water is often less than one metre. The retina has no sensitivity to pain, and the effects of retinal damage may not appear for hours, so there is no warning that injury is occurring. This is very different from typical wind-generated swells on the ocean, which might have a period of about 10 seconds and a wavelength of 150 metres. This damage can result in permanent impairment of vision, up to and including blindness. In open water, tsunamis have extremely long periods (the time for the next wave top to pass a point after the previous one), from minutes to hours, and long wavelengths of up to several hundred kilometres. Looking directly at the photosphere of the Sun (the bright disk of the Sun itself), even for just a few seconds, can cause permanent damage to the retina of the eye, because of the intense visible and invisible radiation that the photosphere emits. A single tsunami event may involve a series of waves of varying heights; the set of waves is called a train. When the Moon disappears at Full Moon by passing into Earth's shadow, the event is properly called an eclipse, but when the Moon passes in front of the Sun, we see an occultation of the Sun by the Moon.

This is the two-dimensional equivalent of the inverse square law in three dimensions. Properly speaking, an eclipse occurs when one object passes into the shadow cast by another object. Although the total or overall loss of energy is small, the total energy is spread over a larger and larger circumference as the wave travels, so the energy per linear meter in the wave decreases as the inverse power of the distance from the source. The term eclipse is actually a misnomer: The phenomenon of the Moon passing in front of the Sun is actually an occultation. A tsunami can cause damage thousands of kilometres from its origin, so there may be several hours between its creation and its impact on a coast, arriving long after the seismic wave generated by the originating event arrives. Slightly more annular eclipses than total eclipses occur, because on average the Moon lies too far away from Earth to cover the Sun completely. Tsunamis act very differently from typical surf swells; they are phenomena which move the entire depth of the ocean (often several kilometres deep) rather than just the surface, so they contain immense energy, propagate at high speeds and can travel great trans-oceanic distances with little overall energy loss. Hence the term annular eclipse.

Large objects such as ships and boulders can be carried several miles inland before the tsunami subsides. In that case, at the time of greatest eclipse there remains a thin annulus (or ring) of brilliant Sun left uncovered. The sheer weight of water is enough to pulverise objects in its path, often reducing buildings to their foundations and scouring exposed ground to the bedrock. When a solar eclipse occurs when the Moon is at or near apogee, however, it appears smaller, and it cannot cover the Sun completely. Most of the damage is caused by the huge mass of water behind the initial wave front, as the height of the sea keeps rising fast and floods powerfully into the coastal area. When a solar eclipse occurs when the Moon is at or near perigee, it appears large enough to cover the bright disk, or photosphere, of the Sun completely, and a total eclipse occurs. Instead it looks rather like an endlessly onrushing tide which forces its way around and through any obstacle. The furthest point in the orbit is referred to as apogee, and the closest point is called perigee.

Although often referred to as "tidal waves", a tsunami does not look like the popular impression of "a normal wave only much bigger". Because the Moon's orbit around Earth is an ellipse rather than a circle, however, at some times during the month the Moon is further away, and at other times it is closer to Earth, than average. However, an extremely large landslide could generate a megatsunami that might have ocean-wide impacts. As seen from Earth, therefore, the Sun and the Moon appear to be about the same size in the sky - about 1/2 of a degree in angular measure. These events can give rise to much larger local shock waves (solitons), such as the landslide at the head of Lituya Bay which produced a water wave estimated at 50 – 150 m and reached 524 m up local mountains. One of the most remarkable co-incidences in nature is that (i) the Sun lies about 400 times as far from Earth as does the Moon, and (ii) the Sun is also about 400 times the diameter of the Moon. Tsunamis caused by these mechanisms, unlike the ocean-wide tsunamis caused by some earthquakes, generally dissipate quickly and rarely affect coastlines distant from the source due to the small area of sea affected. The reason why some solar eclipses are total and others are annular has to do with the elliptical nature of the Moon's orbit around Earth.

These phenomena rapidly displace large volumes of water, as energy from falling debris or expansion is transferred to the water into which the debris falls. There are four types of solar eclipses:. In the 1950s it was discovered that larger tsunamis than previously believed possible could be caused by landslides, explosive volcanic action and impact events. . Waves are formed as the displaced water mass moves under the influence of gravity to regain its equilibrium and radiates across the ocean like ripples on a pond. A total solar eclipse is considered by many to be the most spectacular natural phenomenon that one can observe. Similarly, a violent submarine volcanic eruption can uplift the water column and form a tsunami. This configuration can only occur at New Moon, when the Sun and Moon are in conjunction, as seen from Earth.

Sub-marine landslides; which are sometimes triggered by large earthquakes; as well as collapses of volcanic edifices, may also disturb the overlying water column as sediment and rocks slide downslope and are redistributed across the sea floor. A solar eclipse occurs when the Moon passes in front of the Sun and obscures it totally or partially. Subduction earthquakes are particularly effective in generating tsunamis, and occur where denser oceanic plates slip under continental plates in a process known as subduction. February 16, 1980: Launch of rockets from San Marco platform. Such large vertical movements of the earth's crust can occur at plate boundaries. February 26, 1979: Launch of rockets from Red Lake, Canada. Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. November 12, 1966: Launch of two Titus-rockets fom Las Palmas, Argentina.

An earthquake which is too small to create a tsunami by itself may trigger an undersea landslide quite capable of generating a tsunami. May 20, 1966: Launch of rockets at Karystos, Greece to watch the solar eclipse. However, the most common cause is an undersea earthquake. May 30, 1965: Launch of rockets at Charlestown, USA. A tsunami can be generated by any disturbance that rapidly moves a large mass of water, such as an earthquake, volcanic eruption, landslide or meteorite impact. MacRobert, Sky & Telescope magazine. . How to Watch a Partial Solar Eclipse Safely, Alan M.

However, since they are not actually related to tides the term is considered misleading and its usage is discouraged by oceanographers. Eye Safety During Solar Eclipses, Fred Espenak, NASA Goddard Space Flight Center. Tsunamis have been historically referred to as tidal waves because as they approach land they take on the characteristics of a violent onrushing tide rather than the sort of cresting waves that are formed by wind action upon the ocean (with which people are more familiar). However, some eclipses can only be seen as a partial eclipse, because the central line never intersects the Earth's surface. A tsunami is not a sub-surface event in the deep ocean; it simply has a much smaller amplitude (wave heights) offshore, and a very long wavelength (often hundreds of kilometres long), which is why they generally pass unnoticed at sea, forming only a passing "hump" in the ocean. This phenomenon can usually be seen from a large part of the Earth outside of the track of a central eclipse. The term was created by fishermen who returned to port to find the area surrounding the harbour devastated, although they had not been aware of any wave in the open water. A partial eclipse occurs when the Sun and Moon are not exactly in line, and the Moon only partially obscures the Sun.

Although in Japanese tsunami is used for both the singular and plural, in English tsunamis is well-established as the plural. The generic term for a total, annular or hybrid eclipse is a central eclipse. The term tsunami comes from the Japanese language meaning harbour ("tsu", 津) and wave ("nami", 波 or 浪). At some points on the Earth it is visible as a total eclipse; whereas at others it is annular. The effects of a tsunami can range from unnoticeable to devastating. A hybrid eclipse is intermediate between a total and annular eclipse. Earthquakes, landslides, volcanic eruptions and large meteorite impacts all have the potential to generate a tsunami. Hence the Sun appears as a very bright ring surrounding the outline of the Moon.

A tsunami (IPA pronunciation /suˈnɑːmi/ or /tsuˈnɑːmi/]) is a series of waves generated when water in a lake or the sea is rapidly displaced on a massive scale. An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. 16 October 1979 23 people died when the coast of Nice, France, was hit by a tsunami. During any one eclipse, a total eclipse is visible only from a fairly narrow track on the surface of the Earth. 4 July 1992 - Daytona Beach, FL. The intensely bright disk of the Sun is replaced by the dark outline of the Moon, and the much fainter corona is visible (see image right). 19 May 1964 - Northeast USA. A total eclipse occurs when the Sun is completely obscured by the Moon.

21 September 1938 - Hurricane, NJ coast. 19 August 1931 - Atlantic City, NJ. 8 August 1924 - Coney Island, NY . 6 August 1923 - Rockaway Park, Queens, NY .

9 June 1913 - Longport, NJ. 35 Million years ago - Chesapeake Bay impact crater, Chesapeake Bay. 18 August 1946 - Dominican Republic. 4 August 1946 - Dominican Republic.

9 January 1926 - Maine. 18 November 1929 - Newfoundland. 11 October 1918 - Puerto Rico. 17 November 1872 - Maine.

18 November 1867 - Virgin Islands. 14 November 1840 - Great Swell on the Delaware River. The villages of Arop and Warapu were destroyed. While the magnitude of the quake was not large enough to create these waves directly, it is believed the earthquake generated an undersea landslide, which in turn caused the tsunami.

A 7.1 magnitude earthquake 24 km offshore was followed within 11 minutes by a tsunami about 12 m tall. 17 July, 1998: A Papua New Guinea tsunami killed approximately 2200 people [7]. May 26, 1983: 104 people in western Japan were killed by a tsunami spawned from a nearby earthquake. 1976: On 16 August (midnight) a tsunami killed more than 5000 people in the Moro Gulf region (Cotabato City) of the Philippines.

It travelled at over 150 kph. This happened in the fjord shaped Lituya Bay, Alaska, USA. July 9, 1958: A huge landslip caused the highest ever reported tsunami which was 524 metres high. 1946: An earthquake in the Aleutian Islands sent a tsunami to Hawaii, killing 159 people (five died in Alaska).

A wave more than seven stories tall (about 20 m) drowned some 26,000 people. One of the worst tsunami disasters engulfed whole villages along Sanriku, Japan, in 1896. January 26, 1700: the Cascadia Earthquake (estimated 9.0 magnitude) caused massive tsunamis across the Pacific Northwest. The cause of the flood remains disputed, it is quite possible that it was caused by a combination of meteorological extremes and tidal peaks (discussion).

January 20, 1606/1607: along the coast of the Bristol Channel (main article) thousands of people were drowned, houses and villages swept away, farmland was inundated and flocks were destroyed by a flood that might have been a tsunami. circa 500 C.E.: Poompuhar, Tamil Nadu, India, Maldives. As the wave approaches, the top of the wave may glow red. A flash of red light might be seen near the horizon.

The sea may recede to a considerable distance. or a whistling sound. or a noise akin to the periodic whop-whop of a helicopter,. a roaring noise as of a jet plane.

A thunderous boom may be heard followed by