Hydrophone tsunami earthquake marine

21 JUNE 2008

TO show all of you something interesting and new like i always do:D, TODAY, i am going to put up a video on how are tsunamis detected by the marine hydrophone...
It is not just any phone....
it's an HYDROPHONE...

BY Charlotte LIM


20 JUNE 2008

If you had realised we have been putting a lot of videos for you in this blog... You're absolutely right! The rationale behind the putting of videos is because we believe that picture speaks a thousand words, and videos, A MILLION or maybe even more... and today, i'm putting up an animation to clearly show you how Tsunamis, this EVIRONMENTAL BIG GREAT GREEN ISSUE is created! Seat back relax and enjoy the animation?


tsunami animation

18 JUNE 2008

to have a feel of what tsunami is really like, you can watch this animation..

By Jinny

the deadly force

16 JUNE 2008

Though it's true that tsunamis are ocean waves, calling them by the same name as the ordinary wind-driven variety is a bit like referring to firecrackers and atomic warheads both as "explosives." Triggered by volcanic eruptions, landslides, earthquakes, and even impacts by asteroids or comets, a tsunami represents a vast volume of seawater in motion -- the source of its destructive power.

The Japanese characters for tsunami mean "harbor wave," and many people commonly refer to them as tidal waves, but in reality tsunamis have little to do with tides. They are creatures of the open ocean, trains of giant waves that can travel for thousands of miles across the sea and still pack enough energy to smash towns and drown the unwary.

A tsunami generated in the Aleutian Islands struck Hawaii in 1946.


VIDEO ON Tsunami Hits Thailand & South East Asia!

14 JUNE 2008

BELOW IS A VIDEO on.....Tsunami Hits Thailand & South East Asia!


INDIAN OCEAN tsunami case study II

12 JUNE 2008

BELOW IS A VIDEO ON "What caused the Indian Ocean Tsunami"


Tsunami Case Study: INDIAN OCEAN

10 JUNE 2008

Below is a video on "Environmental damage from the Indian Ocean Tsunami"

We'll most likely find for you a video on what caused the tsunami in Indian Ocean.


more on tsunamis

4 JUNE 2008


1. Heed Natural Warnings
2. Heed Official Warnings
3. Expect Many Waves
4. Head for High Ground and Stay There
5. Abandon Belongings
6. Don’t Count on the Roads
7 .Go to an Upper Floor or Roof of a Building
8. Climb a Tree
9. Climb onto Something that Floats
10.Expect the Waves to Leave Debris
11.Expect Quakes to Lower Coastal Land
12.Expect Company

P.S ( follow it like a bible if you ever land into a tsunami! )


On Sunday, May 22, 1960, Jovita Riquelme took her 5-year-old daughter to Mass in Queule, Chile .During Mass, the priest talked about earthquakes. A swarm of quakes as large as magnitude 8 had occurred 100 miles to the north the previous day.
Later that Sunday, the magnitude 9.5 mainshock of the 1960 Chile earthquake rocked the region. After the shaking ended, many people from Queule decided to head to nearby hills. From their stories it is not known why they chose to do this, but their only known warning was the minutes of shaking or, perhaps, changes in the level of the Río Queule or the nearby Pacific Ocean.
Heeding natural warnings by going to high ground probably saved hundreds of lives in Queule. However, Mrs. Riquelme’s family remained at their house on low ground near the Río Queule. The tsunami that followed the earthquake caught the Riquelme family there. During the confusion caused by the waves, Mrs. Riquelme lost her daughter, and her husband was badly injured. Her husband died of his injuries, and the body of her daughter was found 3 days after the tsunami.
Not far from Queule, Vitalia Llanquimán lived outside the village of Mehuín. Soon after the earthquake shaking stopped, a man on horseback told her that the sea had receded from shore. At first, Mrs. Llanquimán was not alarmed by this news, but her husband took it as a warning that the sea, when it came back, might surge inland. Carrying their two youngest children, the couple hurried up a nearby hill, where they safely remained during the tsunami. Though a mile from the sea, most of Queule, Chile, was overrun and washed away by the tsunami that followed the 1960 Chile earthquake. Many residents of Queule fled to the safety of high ground soon after the earthquake, but Jovita Riquelme lost her daughter and husband to the tsunami because the family remained at their house on low ground near the Río Queule. From the height of debris tangled in the branches of trees that remained standing after the 1960 tsunami, Wolfgang Weischet, then a geographer at the Universidad Austral de Chile in nearby Valdivia, estimated that water from the tsunami was as much as 13 feet deep in Queule. Mr. Weischet took these before and after photos.

here's a good link to know more about tsunamis

by charlotte

MORE information about the killer of many!

1 JUNE 2008

What are tsunamis and what causes them?
Tsunamis -- sometimes incorrectly called tidal waves -- are extremely powerful waves caused by large undersea disturbances. (The name tsunami derives from Japanese for "harbor wave," reflecting the fact that harbors can concentrate the energy of a tsunami. True tidal waves, also known as tide waves, are long-period waves associated with the tide-producing forces of the moon and the sun and which are identified with the rising and falling of the tide.) Although landslides and volcanoes cause some tsunamis, probably 95 percent result from earthquakes -- usually under the ocean floor but occasionally near shore. Because the volume of water is essentially constant, up or down movement of the sea floor will raise or lower the water above it, causing a wave. Similarly, you can make a (somewhat smaller) wave by throwing a stone in a pond.

Vertical movement of the ocean floor will raise or lower the water above it, causing waves that move outward. Almost undetectable in the deep ocean, tsunamis rise to a mighty crest as the ocean shallows.

Just as a larger stone, thrown with more force, makes a larger wave, the size of the tsunami is related to the area that moves on the ocean bottom, and how far it moves. Obviously, more movement of a larger piece of ocean floor makes a larger wave.

The intensity at which a tsunami strikes land is also related to the distance between the land and the center of the earthquake. It's here, at the epicenter, that the tsunami originates. As the waves spread from the epicenter in the typical arc-shaped pattern, their energy also spreads out, making tsunamis usually most dangerous to those closest the epicenter.

Spread out, but still powerful
One factor that distinguishes tsunamis from small, familiar waves is their extremely long wavelength. On the open ocean, the peaks of neighboring waves in a tsunami may be 300 kilometers -- you read that right: 300 kilometers! -- apart.

Even in the deepest ocean, that wavelength makes tsunamis what scientists call "shallow water waves." The speed of a shallow-water wave depends on the water depth, and in deep water, tsunamis can move at 500 to 600 miles per hour. That gives them the ability to keep pace with a Boeing 747, yet even after crossing the entire Pacific Ocean, the waves retain huge amounts of energy.

But you wouldn't see a tsunami from the cockpit of a 747. A killer tsunami may be only 2 feet tall in mid-ocean -- far too small to be noticed from an airplane or even a ship.

Although waves are most obvious at the water surface, the motion actually goes much deeper. That's why the ocean bottom can affect a wave's shape, height and force.

How can all that destructive kinetic energy hide in waves that we can barely see? Because waves are far more than what you can see on the surface -- they also include the nearly circular movement of water below the surface. Because long-wavelength waves extend far deeper into the water than waves with peaks closer together, there's a massive amount of water in motion beneath the surface. That's where these practically invisible waves store an enormous amount of energy.

As we've indicated, boats in deep water ride over the worst tsunamis without even noticing them. It's only when they reach shallow water and "run aground" that these waves become intense and dangerous. Like all shallow water waves, tsunamis slow when the lower part of the wave -- where the water is moving in a circle -- encounters the bottom as the ocean floor slopes up toward land.

But while the front of the wave slows, the wave behind is still moving rapidly, causing a giant pile-up at the front. Then the kinetic energy that was spread through the entire depth of the ocean becomes concentrated in a towering wave at the surface.

It is these surface waves -- which can be 10 meters high or taller as they cross the beach -- that cause the utter destruction of tsunamis. Usually, a series of waves, often as much as an hour apart, come crashing in -- killing those who return to help victims of the previous waves.


know more about the KILLER WAVES

28 MAY 2008

How do they form?

Tsunamis are formed as a result of earthquakes, volcanic eruptions, or landslides that occur under the sea. When these events occur under the water, huge amounts of energy are released as a result of quick upward bottom movement. For example, if a volcanic eruption occurs, the ocean floor may very quickly move upward several hundred feet. When this happens, huge volumes of ocean water are pushed upward and a wave is formed. A large earthquake can lift thousands of square kilometers of sea floor which will cause the formation of huge waves. The Pacific Ocean is especially prone to tsunamis as a result of the large amount of undersea geological activity.

How big do they get?

In the open ocean tsunamis may appear very small with a height of less than 1 meter (3 feet). Tsunamis will sometimes go undetected until they approach shallow waters along a coast. These waves have a very large wavelength (up to several hundred miles) that is a function of the depth of the water where they were formed. Although these waves have a small height, there is a tremendous amount of energy associated with them. As a result of this huge amount of energy, these waves can become gigantic as they approach shallow water. Their height, as they crash upon the shore, depends on the underwater surface features. They can be as high as 30 m (100 feet) or more. In 1737 , a huge wave estimated to be 64m (210 feet) in height hit Cape Lopatka, Kamchatka (NE Russia). The largest Tsunami ever recorded occurred in July of 1958 in Lituya Bay, Alaska. A huge rock and ice fall sent water surging up to a high water mark of 500m (1640 feet). It's no wonder that these waves can cause such massive destruction and loss of life.

How fast do they move?

In the deep open sea, tsunamis move at speeds approaching a jet aircraft. As they approach the shore, they slow down. When a tsunami arrives at the shore, it usually does so as a rapidly rising tide moving at about 70 km/hour (45 miles/hour).

How much destruction do they cause?

Beyond the tremendous destruction of life that tsunamis cause, they have also caused massive physical damage. They have entirely destroyed buildings and left towns looking like a nuclear war zone. They have lifted boats high out of the water and violently hurled them against the shore, smashing them to pieces. They have bent parking meters all the way down to the ground. In one incredible story, during the huge tsunami in Lituya Bay, Alaska (mentioned above), a boat with two people in it was carried from the bay, over tree tops and over the land out into the ocean. The people survived to tell the tale.

Can we detect them before they hit?

Yes. About 35 years ago, 24 countries around the Pacific set up the Pacific Tsunami Warning System. A group of seismic monitoring stations and a network of tide gauges are used for detection. The biggest problem with this system is that it is difficult to predict how large and destructive the resulting waves will be. Scientists are currently working on better predictive tools.



25 MAY 2008

Tsunamis are obviously waves and as such they follow the fundamentals of waves. These basics are as follows:

Get the Picture???

The wavelength is the length from crest to crest, and the amplitude is the distance from the bottom of the trough to the top of the crest. The period is the length of time for one crest to travel the distance to where the other crest was.

A vertical displacement in the water column at sea creates waves that become tsunamis. While at sea these waves have a VERY large wavelength (approximently 500 kilometers), but their overall amplitude is very small (about a meter). In the ocean, a tsunami could pass beneath the boat that you are on and you would hardly notice it! Because of the very large wavelength, the wave loses very little energy as it moves along the ocean, thus allowing tsunamis to inflict damage hundreds of miles away. As these waves approach the shore, they start to behave differently (like shallow water waves instead of deep water waves) and their wavelength becomes smaller and the amplitude becomes much taller.

Tsunami Forming



The picture above clearly illustrates the wavelength becoming smaller and the amplitude rising suddenly.

The position of a wave is defined as x(t) = A cos(ωt + φ) where A is the amplitude, ω is the period, and φ is the phase constant.

The velocity of a tsunami is dependant on only one factor: the depth of the ocean over which it is traveling. The maximum velocity of a tsunami can be up to 800 kilometers an hour.

Thus the velocity is equal to the square root of g (gravitational constant 9.81 m / s^2) times the average depth of the ocean. This method was used estimate the average depth of the ocean between Hawaii and Alaska in 1856 before the advent of sonar and modern depth techniques. The scientists knew the amount of time it took for the tsunami to reach Hawaii from Alaska, and also the distance, so they thus knew the velocity. Since g is already known, they simply solved for the average ocean depth.

Another factor in the creation of tsunamis is the depth of the earthquake. If the earthquake occurs more than 100 km below the surface, a tsunami will not occur because there is not enough vertical displacement of the water.


These images show how the tectonic plates collide creating an earthquake and a vertical displacement in the water.

Quake Centered in Aleutians, based on 1999 quake


As can be clearly seen from the picture above, tsunamis extend radially from the source of the earthquake, much as if a pebble had been thrown into a pond.

If you have adiquate bandwidth watch this animation of a tsunami spreading across the Pacific (several Mb) http://www.pmel.noaa.gov/tsunami/Mov/andr1.mov



23 MAY 2008

go to this website, it has many videos on tsunami, very enriching!


On Dec. 26, 2004, a 9.0 magnitude earthquake—the largest earthquake in 40 years—occurred off the west coast of the Indonesian island of Sumatra. The earthquake triggered a tsunami in the Indian Ocean, the deadliest in world history. More than 226,000 died and twelve countries felt the devastation.

The most infamous tsunami of modern times hit Indian Ocean shorelines on the day after Christmas 2004. That tsunami is believed to have packed the energy of 23,000 Hiroshima-type atomic bombs. Some 150,000 people were killed in a single day.


The 2004 Indian Ocean earthquake was an undersea (subduction) earthquake that occurred at 00:58:53 UTC on December 26, 2004, with an epicentre off the west coast of Sumatra, Indonesia. The earthquake triggered a series of devastating tsunamis along the coasts of most landmasses bordering the Indian Ocean, killing more than 225,000 people in eleven countries, and inundating coastal communities with waves up to 30 meters (100 feet). It was one of the deadliest natural disasters in history. Indonesia, Sri Lanka, India, and Thailand were hardest hit.
With a
magnitude of between 9.1 and 9.3, it is the second largest earthquake ever recorded on a seismograph. This earthquake had the longest duration of faulting ever observed, between 8.3 and 10 minutes. It caused the entire planet to vibrate as much as 1 cm (0.5 inches)and triggered other earthquakes as far away as Alaska. The disaster is known by the scientific community as the Great Sumatra-Andaman earthquake, and is also known as the Asian Tsunami and the Boxing Day Tsunami. The tsunami occurred exactly one year after the 2003 Bam earthquake and exactly two years before the 2006 Hengchun earthquake.
The plight of the many
affected people and countries prompted a widespread humanitarian response. In all, the worldwide community donated more than $7 billion (2004 U.S. dollars) in humanitarian aid.



18 MAY 2008



Waves & Transference of Energy

13 May 2008

Waves & Transference of Energy

Wave is a transfer of energy, in the form of disturbance through some medium, without translocation of the medium. A wave having a short duration is called pulse. Waves that vibrate in repeating cycles illustrate periodic motion or harmonic motion. One complete oscillation is called cycle.

There are three main types of waves. These types of waves are grouped according to how they travel, or WAVE MOTION.

Mechanical waves. Mechanical waves need a material medium to travel (ropes, water, or air are examples).

These waves are divided into three different types:
Transverse waves - these waves cause the material to move perpedicular to the direction of wave travel.

Longitudinal waves - these waves cause the material to move parallel to the direction of wave travel.

Surface waves - these waves are both transverse and longitudinal waves mixed in one medium.

Electromagnetic waves. Electromagnetic waves do not require a medium to travel. Examples of this type of wae include light and radio waves.

Matter waves are produced by electrons.

So how do waves move? Waves transfer energy from a vibrating source through whatever medium it is in. For example, if you drop a pebble into a pond, you’ll make a wave that moves out from the center in an expanding circle. The water DOES NOT move. It is the disturbance that moves. After the disturbance passes, the water is exactly where it was before the wave passed. When someone speaks to you from across the room, the sound wave travels through the air as a disturbance in wave form. The air molecules themselves do not move. If the air molecules themselves moved, we would call that wind.

Mechanical waves require a medium. What is a medium? Examples include air, water ropes, a string, etc. A medium is any substance that has molecules and can transfer energy in the form of a wave. Does the type of medium have any effect on wave travel? Of course! Sound travels differently through air than it does through water. In fact, sound travels through cold air differently than it travels through hot air. A wave is just a transfer of energy from molecule to molecule, and so on and so on, until there is no more medium to transmit the wave. That energy is then reflected backward. Think of an echo - once the sound wave reaches solid ground, it can be reflected back toward its source. How well energy is reflected depends upon the density of the medium that is transferring the energy.

Whatever the medium, the speed, frequency, and wavelength of a wave are related to each other, and that relationship is described by the following equation:

Wave speed (γ) = frequency (ƒ) x wavelength (λ)

This relationship holds true for all types of waves.

All mechanical waves require a medium of some sort to transfer energy. Mechanical waves are divided into three types: transverse, longitudinal, and surface.

Transverse waves cause the material to move perpendicular to the direction of wave travel. Click on the diagram with the green dots. The wave will travel to the right, and so you need to make the green dots (or molecules) move up and down. (This should create right angles, for you geometry lovers out there!) Stringed instruments and waves upon the surface of liquids are transverse, as are the electromagnetic waves of light and radio.

Longitudinal waves cause the material to move parallel to the direction of wave travel. If the wave is moving to the right, you need to make the green molecules move left and right (the same direction as the wave travel).

Both of these types of waves transfer energy. Surface waves are a combination of transverse and longitudinal waves. This means that the wave needs to move left and right as well as up and down.


By Fiona

Savage Earth: Waves of destruction!

08 May 2008

Though it's true that tsunamis are ocean waves, calling them by the same name as the ordinary wind-driven variety is a bit like referring to firecrackers and atomic warheads both as "explosives." Triggered by volcanic eruptions, landslides, earthquakes, and even impacts by asteroids or comets, a tsunami represents a vast volume of seawater in motion -- the source of its destructive power.

The Japanese characters for tsunami mean "harbor wave," and many people commonly refer to them as tidal waves, but in reality tsunamis have little to do with tides. They are creatures of the open ocean, trains of giant waves that can travel for thousands of miles across the sea and still pack enough energy to smash towns and drown the unwary.

Tsunami threatening to drown the unwary

Toss a stone in a pond and you create a series of concentric ripples. A tsunami is just like those ripples, except the disturbance that sets them in motion is of a much greater magnitude. Undersea landslides and the collapse of oceanic islands into the sea make tsunamis. Volcanic eruptions can also do it. In fact, the most deadly tsunami in recorded history followed the eruption and virtual obliteration of Indonesia's Krakatoa Volcano in 1883. An estimated 36,000 people died as a result of the eruption, the majority of them from the tsunamis.

Krakatoa Volcano in Indonesia

On the open ocean, tsunami waves approach speeds of 500 mph, almost fast enough to keep pace with a jetliner. But gazing out the window of a 747, you wouldn't be able to pick it out from the wind-driven swells. In deep water, the waves spread out and hunch down, with hundreds of miles between crests that may be just a few feet high. A passenger on a passing ship would scarcely detect their passing. But in fact the tsunami crest is just the very tip of a vast mass of water in motion. Though wind-driven waves and swells are confined to a shallow layer near the ocean surface, a tsunami extends thousands of feet deep into the ocean.

Because the momentum of the waves is so great, a tsunami can travel great distances with little loss of energy. The 1960 earthquake off the coast of Chile generated a tsunami that had enough force to kill 150 people in Japan after a journey of 22 hours and 10,000 miles. The waves from a trans-Pacific tsunami can reverberate back and forth across the ocean for days, making it jiggle like a planetary-scale pan of Jell-O.

As the waves in the tsunami reach shore, they slow down due to the shallowing sea floor, and the loss in speed is often accompanied by a dramatic increase in wave height. The waves scrunch together like the ribs of an accordion and heave upward. Depending on the geometry of the seafloor warping that first generated the waves, tsunami attacks can take different forms. In certain cases, the sea can seem at first to draw a breath and empty harbors, leaving fish flopping on the mud. This sometimes draws the curious to the shoreline and to their deaths, since the withdrawing of the sea is inevitably followed by the arrival of the crest of a tsunami wave. Tsunamis also flood in suddenly without warning. Tsunami waves usually don't curve over and break, like Hawaiian surf waves. Survivors of tsunami attacks describe them as dark "walls" of water. Impelled by the mass of water behind them, the waves bulldoze onto the shore and inundate the coast, snapping trees like twigs, toppling stone walls and lighthouses, and smashing houses and buildings into kindling.



02 May 2008

"Pressure" is the ratio of a normal force to the area on which the force acts.
Hydrostatic Pressure

Think of a column of fluid of height h and cross sectional area A. The fluid has a density rho. The pressure P at the base of the column is by definition the force exerted on the base divided by the area A; that force is the weight of the column plus any force acting on the top.

This is the formula for the pressure due to a column of fluid, or "hydrostatic pressure".


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.

A tsunami wave in deep water creates a small but measurable change in pressure that will be maintained for as long as twenty minutes.

Tsunamis have tremendous force because of the great volume of water affected and the speed at which they travel. Just a cubic yard of water, for example, weighs about one ton. Although the tsunami slows to a speed of about 48 km/h (30 mph) as it approaches a coastline, it has a destructive force equal to millions of tons.

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.

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.

The wave travels across open ocean at an average speed of 500 mph.

The passing "hump" mentioned earlier is a "momentum flux" equal to density multiplied by the square of the velocity. This gives the transient pressure built up during the quake as equal to twice and in addition to the hydrostatic pressure. There is no proof for this.


Pressure Waves and Shockwaves
As any object moves through the atmosphere is creates pressure waves. These are simply small disturbances caused by forcing air molecules closer together. These disturbances are then transmitted through the atmosphere, just like waves passing energy through the ocean.

A GOOD WEBSITE ON WAVE PRESSURE: http://www.pwri.go.jp/eng/ujnr/joint/37/paper/13kato.pdf

Sources used:



TSUNAMI's effects on the green

28 APRIL 2008

For an example of how the environment effects a tsunami, the environment has to be in precise conditions for a tsunami to occur. A tsunami does not just happen out of the middle of the ocean, something has to cause it. On the simplest level tsunamis can be caused by an earthquake, but getting more in depth, the earthquake has a cause, that cause would be movement in tectonic plates, but what causes the movement in the tectonic plates? Is there a never ending cycle of events causing larger events causing larger events until one of them finally catches the human kinds notice and we take the incentive to do something about it. The moving of Tectonic plates is caused by something moving in one of the deeper layers of the earth. Something below the crust. The reason small movements are able to create earthquakes is that because the top 40 killometers of the earths crust are made up of tectonic plates, which rest upon magma which is constantly moving and so moving the plates. So, when a tectonic plate does get moved, it creates an earthquake, which creates an tsunami.

Damage from the tsunami can be very significant. But this damage does NOT seem all that significant to the environment .But behind the scenes lurks hidden damage. All of the damage from the tsunami, such as all the destroyed buildings, with fluids draining from these and leaking back into the ocean, into other farm land, or into rural areas. All of the fluids leaking from the buildings can harshly damage the environment by flooding into the oceans, where it may be drunk by sea creatures, or flowing into the farm land or just fields where it may ruin perfectly good soil. Not only does this damage the fish and ocean environment but it damages the human environment by ruining the economy. After the East India Tsunami the sea exports coming from East India took a hit of 30%. This was mainly because consumers were afraid the fish would be contaminated by the thousands of dead bodies which were washed out to sea.

Tsunamis are also effected by the miles of coral reef often surrounding the places where tsunamis are likely to hit. Without coral reef the damage from a tsunami would be many times greater to the environment. Many scientist believe that nature never totally destroys itself, it always has a way to rebuild itself after a natural disaster, or has a way of preventing excess damage in the first place. Take in a forest the cycle of life, the forest starts out with just grass and things like fireweed, this makes a perfect living and growing environment for when small bushes and trees, which then makes way for larger trees, until eventually a forest fire destroys the forest. This makes way for very rich soil and lets grass grow again which starts the chain over. Tsunamis have relation to that cycle in that nature prevents demolishing it self by using its coral reef to slow down the tsunami. We know that it is true that the coral reefs reduced damage done by the tsunami because where there where healthy coral reefs, the damage was not as bad (during resent East Asia tsunami) The reason the coral reefs can effect the tsunami is that the reef structure absorbs some of the wave energy before it reaches shore. Two islands in the the east of east Asia called Andoman and Nickobar, which home nearly 200 different types of coral reef, and nearly 400 types of fish species were nearly totally destroyed.
Obviously the damage to the environment is very widespread. During the east Asia tsunami more than 350 sea turtles were killed. Many endangered hump back dolphins were also killed, and along with the damage to the endangered species much of the fresh water was poisoned with salt water and debris. The tsunami also turned once normal crop fields into lakes of sea water.The salt seriously damages the soil's ability to grow crops.


How are tsunami waves formed and why do they affect the environnement so much?

21 APRIL 2008

When a sudden displacement of a large volume of water occurs, or if the sea floor is suddenly raised or dropped by an earthquake, big tsunami waves can be formed by forces of gravity. The waves travel out of the area of origin and can be extremely dangerous and damaging when they reach the shore.
Tsunami are also known as "seismic or tidal sea wave" however the terms are misleading, because tsunami waves can be generated by other, non seismic disturbances such as volcanic eruptions or underwater landslides, and have physical characteristics different of tidal waves.

Tsunami caused by earthquakes---
the most destructive tsunamis are generated from large, shallow earthquakes with an epicenter or fault line near or on the ocean floor. These usually occur in regions of the earth characterized by tectonic subduction along tectonic plate boundaries. The high seismicity of such regions is caused by the collision of tectonic plates. When these plates move past each other, they cause large earthquakes, which tilt, offset, or displace large areas of the ocean floor from a few kilometers to as much as a 1,000 km or more. The sudden vertical displacements over such large areas, disturb the ocean's surface, displace water, and generate destructive tsunami waves. The waves can travel great distances from the source region, spreading destruction along their path. it takes an earthquake with a Richter magnitude exceeding 7.5 to produce a destructive tsunami.

Tsunami caused by volcanic eruptions---
violent volcanic eruptions represent also impulsive disturbances, which can displace a great volume of water and generate extremely destructive tsunami waves in the immediate source area. According to this mechanism, waves may be generated by the sudden displacement of water caused by a volcanic explosion, by a volcano's slope failure, or more likely by a phreatomagmatic explosion and collapse/engulfment of the volcanic magmatic chambers.
Tsunami generated by submarine landslides, rock falls and underwater slumps-----
tsunami waves can be generated from displacements of water resulting from rock falls, icefalls and sudden submarine landslides or slumps. Such events may be caused impulsively from the instability and sudden failure of submarine slopes, which are sometimes triggered by the ground motions of a strong earthquake. Major earthquakes are suspected to cause many underwater landslides, which may contribute significantly to tsunami generation the energy of tsunami waves generated from landslides or rock falls is rapidly dissipated as they travel away from the source and across the ocean, or within an enclosed or semi-enclosed body of water - such as a lake or a fjord. BUT, the largest tsunami wave ever observed anywhere in the world was caused by a rock fall in Lituya Bay, Alaska on July 9, 1958.

by WeiQing

Tsunami's Effects: Man, And The Sea II

18 APRIL 2008
Tsunamis And Sea Life?

The described effects of tsunamis, as far as we have found, haven't taken into account how sea life is affected other than as a side note. With this tsunami, the effect on sea life and the associated ecosystems could well be massive.

When researching this entry, one of the most disturbing things we found was that there was very little available information regarding how sea life is affected. Without prior information, it's difficult to ascertain just how much of an impact that the tsunami will have on fishing, and subsequently, the region's economy. This is definitely an area where tsunami experts may wish to study - it's unlikely that this will be the last tsunami that humanity will encounter. The potential impact on humanity - through food and economy - gives such a study merit. As mentioned in an email in 1998 regarding underwater 'storms':

...Earthquakes can raise tsunami that act impact as huge unexpected waves when they arrive in shallow water. Unless the earthquake is near enough for animals to have sensed the vibrations and hidden, they will caught in the open by this large wave. In the 1750 Lisbon earthquake, reports record that the sea withdrew like a giant low tide, leaving fish flopping around on the seabed. People who went out to view this phenomenon, or to collect the fish, were drowned when the tsunami crashed back over the beaches...

In this particular scenario, it's easy to hypothesize that fish caught on the inside of the tsunami, had they sensed it, would have headed away from it - which would have been, in this massive bay, toward land. In doing so, they may have unwittingly become caught up in the wave. As the tsunami approaches land, it gains height even as it slows down. This would affect sea life within 1 kilometer of land, and perhaps even more depending on the depth of the tsunami in the open sea.

Deeper in the ocean, in the region of the earthquake, many things could have happened. Deformation of the sea floor is almost assured with an earthquake of this strength - but how the sea floor became deformed is open to speculation. That's really the bottom line with this tsunami - it's almost a theme - "We Do Not Know."

Because we do not know, it is time for us to start trying to find out. Maybe somewhere, there's a group of people working on this. And again, with all efforts being pointed toward saving the lives of our brothers and sisters, maybe it isn't. Yet knowing how much of an effect has been had on the sea life may well prepare the countries in the region for long term actions; while aid in the form of assistance and money rolls in, the long term effects will determine the long term assistance needed.


Tsunami's Effects: Man, And The Sea I

14 APRIL 2008

Fishing Impact

Historically, tsunamis have impacted sea life. Large waves overrun masses of land, and leave in the treetops and
sea creatures on land. It's an odd twist that the tsunami trades land animals for sea animals in this way. How many fish were washed ashore on December 26th? How many reefs were damaged?

While we ponder immediate problems and immediate solutions, it's important that evaluation of the actual fish is done. Where literally millions of fish may have died, and where the habitats of the fish nearer the coast have almost certainly been affected, there is no apparent data based on previous tsunamis to indicate the effect on ocean life – and subsequently, human lives that depend on this ocean life. Consider Coral reefs may take years to recover from tsunamis - and therefore, so may the fish. The Coral Reef Heritage of India is a strong one. What will the poor fisherman, who has had his boat wrecked and has lost income over the last few days, catch in the next few months?

While society has been aware of the effects of fishing and overfishing for quite some time, the numbers tend to be human-centric. We've tried to make made it illegal for humans to inadvertently decimate fish stock although Mother Nature can do it with impunity. This doesn't excuse deep sea scraping; instead it makes humanity's effect on sea life more important. What we call a calamity under cover of a tsunami is something which we actually do ourselves –a natural catastrophe. It's not usually the humble coastal fisherman who does this, instead the larger fishing operations – yet the price paid is one of hunger.



6 APRIL 2008


Warning signs of TSUNAMI

1. If you are at the beach or near the ocean and feel the earth shake, run immediately to higher ground. Do not wait for a tsunami warning to be given.

2. The sudden draw down of the sea level resulting in a receding shoreline, sometimes by a kilometre or more, is a sign of a preceding or in-between crest of tsunami waves. Head for high ground as quickly as possible.

3. Do not approach the beach to investigate.

4. If you are advised to evacuate, do so immediately.

BUT, dont worry, we wont be affected cause

Singapore is sheltered from tsunamis by the surrounding land masses, such as Peninsula Malaysia in the north, the Indonesian Archipelago in the west and south, and Borneo in the east. The risk of Singapore being affected directly by a tsunami would therefore be very low. Notwithstanding this, Singapore has since the mid-90s established a seismic monitoring system. The system managed by the Meteorological Services Division monitors tremor activity.

yup so we are kind of safe from it :)

this only applies if you're not in singapore,

What You Should Do if You are Caught in a Tsunami

1. Move quickly to higher ground

Homes and buildings located in low lying coastal areas are not safe.
Do not stay in such buildings if there is a tsunami warning.
Move quickly to higher ground.

2. Seek shelter in reinforced buildings

The upper floors of high multi-storey, reinforced concrete buildings can provide refuge if there is no time to quickly move inland or to higher ground.

3. Move out to deeper waters

If you are on a boat or ship and there is time, move your vessel out to deeper waters.
If there is severe weather, it may be safer to leave the boat at the pier and move to higher ground.

4. Wait for the "ALL CLEAR" signal

Stay away from the area until it is safe.
Do not be fooled into thinking that the danger is over after a single wave– a tsunami is NOT a single wave but a series of waves that can vary in size.


like whoa look at her melons!

by charlotte


3 APRIL 2008

Formation of Tsunamis

When two plates come into contact at a region known as a plate boundary, a heavier plate can slip under a lighter one. This is called subduction. Underwater subduction often leaves enormous "handprints" in the form of deep ocean trenches along the seafloor.
In some cases of subduction, part of the seafloor connected to the lighter plate may "snap up" suddenly due to pressure from the sinking plate. This results in an earthquake. The focus of the earthquake is the point within the Earth where the rupture first occurs, rocks break and the first seismic waves are generated. The epicenter is the point on the seafloor directly above the focus.
When this piece of the plate snaps up and sends tons of rock shooting upward with tremendous force, the energy of that force is transferred to the water. The energy pushes the water upward above normal sea level. This is the birth of a tsunami.


1. the biggest tsunami recorded was a 9.0 on the richter scale! (normally, a 7.0 is horrid enough)

2. sharks are washed up together with the water, you may get eaten!

3. once in motion, it cannot be stopped

4. it destroys EVERYTHING


More about TSUNAMIS!

30 MARCH 2008
What is a TSUNAMI?

1. A tsunami is is a wave train, or series of waves.

2. It is generated in a body of water by a disturbance that vertically displaces the water column.

3. Earthquakes, landslides, volcanic eruptions and explosions, can generate tsunamis.

4. Tsunamis can savagely attack coastlines, causing devastating property damage and loss of life.

Top picture - A normal wave which comes and goes without flooding higher areas
Bottom picture - A tsunami which runs over the high land as a wall of water


Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water.

Tectonic earthquakes are a particular kind of earthquake that are associated with the earth's crustal deformation. When these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position. Waves are formed as the displaced water mass attempts to regain its equilibrium. When large areas of the sea floor elevate or subside, a tsunami is created.

What happens to a TSUNAMI as it approaches land?

As a tsunami leaves the deep water of the open ocean and travels into the shallower water near the coast, it transforms.

A tsunami travels at a speed that is related to the water depth - hence, as the water depth decreases, the tsunami slows. The tsunami's energy flux, which is dependent on both its wave speed and wave height, remains nearly constant. Consequently, as the tsunami's speed diminishes as it travels into shallower water, its height grows.

Thus, due to this shoaling effect, a tsunami, imperceptible at sea, may grow to be several meters or more in height near the coast and is highly destructive.



25 MARCH 2008

A beach littered with debris and fallen trees.
February 2005 Koh Phi Phi, Thailand

Coral reef destruction
February 2007
Koh Phi Phi, Thailand

Devastation of the inland fishing area

March 2005
Nagappattinam, India

The vegetation was stripped off the rock in

the background of probably 20 to 30 feet high.
Loose sedimentary material with rock particles
filled the river mouth.
March 2005
Mouth of the Indian Ocean

"When the tsunami hit some inland villages
in the Nagappattinam area of India, it didn’t
destroy homes or take lives as it did in the
more coastal areas. Instead, in villages
composed of inland fishermen and farmers,
the tsunami took away people’s livelihoods. It
destroyed inland fishing areas and covered
farmland with more than a foot of sand."
-Reclaiming What the Tsunami Took Away

" The natural disaster causes the suffering
for human as well as animals.
There are 6
wildlife left in Wulandari mini zoo in Banda
Aceh in a very poor condition and hungry. These
species are; monkey (pig tail macaque), angora
cat, python, turtle and crane/stork. The owner
of the zoo has fled the area when the disaster
struck, and left the wildlife behind.
ProFauna team visited this mini zoo,
is no food available for these wild animals.
The cages are full of rubbish and are flooded.

" Sadly those rescued wildlife placed at
(council of conservation of natural
resources) site in Aceh also affected by the
disaster. The cages are destroyed. On the ruined
cages there is evidence of clumps of tiger’s
flesh and fur, we have no idea what is the
fate of that tiger

-Tsunami, Human and Animal in Aceh



16 MARCH 2008


I'm here to spread information about superposition of waves.

To put it simple, the princple of wave superposition is when two or more waves travel through the same medium simultaneously, the waves pass through each other without being disturbed.

Definition of principle of superposition and detailed explanation can be found here:

Two sites that have Java applets to show superposition of waves: (Please check them out!)

A video on water interacting with floating boom:

And one interesting fact which I found!
Overlapping ripples are a form of superposition!
Found here: http://www.iop.org/activity/education/Teaching_Resources/Teaching%20Advanced%20Physics/Vibrations%20and%20Waves/Superposition/page_4505.html


That's all. Byeeeeeeeee!

By Jinny


12 MARCH 2008


Green Issue
Tsunamis bring huge environmental damages with them. For example:
- Beaches have been washed away or littered with debris
- Rivers are filled with trash and silt (loose sedimentary material with rock particles usually 1⁄20 millimeter or less in diameter)
- Coral reefs damaged in polluted water
- Endanger animal species living in or near the sea
- Rendering farm land useless

Physics Principles Involved
- Principle of pressure: Pressure = Force/Area or Pressure due to a liquid column
(To find out the amount of pressure the waves contain & the amount of force exerted over an area)
- Waves with it transference of energy and vibration
- Principle of superposition of waves

By Jinny