Life of a Tsunami

Life of a Tsunami
How are tsunamis formed...

Panel 1—Initiation: Earthquakes are typically linked to ground shaking caused by elastic waves moving through the solid earth.

However, in the vicinity of submarine earthquakes, the seafloor experiences a "permanent" uplift and down-drop, which causes the entire water column to oscillate vertically. The potential energy generated from elevating water above the mean sea level is subsequently converted into the horizontal movement of the tsunami wave (kinetic energy). In the example illustrated above, the earthquake rupture took place at the base of the continental slope in relatively deep waters. There are also instances where the earthquake rupture occurs beneath the continental shelf in significantly shallower waters.

Note: In the accompanying figure, the waves are significantly exaggerated in comparison to the water depth. In the open ocean, the waves typically reach a height of only a few meters, extending over distances of many tens to hundreds of kilometers.

Panel 2—Split: Within a few minutes following the earthquake, the initial tsunami (Panel 1) divides into two distinct tsunamis: one that moves out into the deep ocean (distant tsunami) and another that heads towards the nearby coastline (local tsunami). The height above mean sea level of these two oppositely directed tsunamis is roughly half that of the original tsunami (Panel 1). (This is somewhat altered in three dimensions, but the fundamental concept remains.) The velocity at which both tsunamis propagate is proportional to the square root of the water depth. Consequently, the deep-ocean tsunami travels at a faster rate than the local tsunami near the shore.

Panel 3—Amplification: As the local tsunami progresses over the continental slope, several phenomena occur. The most apparent is the increase in amplitude. Additionally, the wavelength diminishes. This leads to the steepening of the leading wave—an essential factor influencing wave runup at the coast (as shown in the next panel). It is important to note that the initial part of the wave that reaches the local shore is a trough, which will manifest as the sea receding significantly from the shore. This serves as a common natural warning sign for tsunamis.

Note also that the deep ocean tsunami has traveled much farther than the local tsunami because of the higher propagation speed. As the deep ocean tsunami approaches a distant shore, amplification and shortening of the wave will occur, just as with the local tsunami shown above.

Panel 4—Runup: Tsunami runup takes place when a peak of the tsunami wave moves from the near-shore area onto the land. Runup serves as a measurement of the height of the water observed onshore above a reference sea level.

With the exception of the most significant tsunamis, such as the 2004 Indian Ocean event, the majority of tsunamis do not produce massive breaking waves (unlike typical surf waves at the beach that curl as they approach the shore). Instead, they arrive similarly to very strong and rapidly moving tides (i.e., powerful surges and swift fluctuations in sea level). A considerable portion of the destruction caused by tsunamis is attributed to strong currents and floating debris.

The limited number of tsunamis that do break often create vertical walls of turbulent water known as bores. Tsunamis frequently travel much further inland than standard waves.

Do tsunamis cease once they reach land? 

No! Following runup, a portion of the tsunami's energy is reflected back into the open ocean and dispersed by abrupt changes in the coastline. Furthermore, a tsunami can produce a specific type of coastal trapped wave referred to as edge waves, which move back and forth parallel to the shore. These phenomena lead to multiple arrivals of the tsunami at a specific location along the coast, rather than a single wave as indicated by Panel 3. Due to the complex behavior of tsunami waves near the coastline, the first runup of a tsunami is often not the most significant, highlighting the necessity of avoiding a return to the beach many hours after the initial impact of a tsunami. How are tsunamis generated..

Tsunami

TSUNAMI

A tsunami consists of a series of waves generated in an ocean, sea, or other water bodies due to an earthquake, landslide, volcanic eruption, or meteorite impact. When these tsunamis reach coastlines, they can inflict significant destruction. Although some individuals refer to tsunamis as "tidal waves," this term is misleading as these large waves are not primarily related to tides.

Tsunami waves differ from the typical waves that roll into the shores of lakes or oceans. The latter are generated by wind offshore and are relatively small compared to tsunami waves. In the open ocean, a tsunami wave can span over 100 kilometers, which is approximately the length of 1000 American football fields! These waves are massive and can travel at speeds of about 700 km/hr, yet they are only about one meter high in the open ocean.

As a tsunami wave approaches shallower waters near the coast, it decelerates and increases in height. While a tsunami may be barely noticeable at sea, it can rise to several meters near the shore, carrying an immense amount of energy. Upon reaching the coast, a tsunami may manifest as a rapidly rising or falling tide or as a series of waves that can reach heights of 25 to 30 meters.

Moments before a tsunami wave strikes, the water near the shore may recede, revealing the ocean floor. It is important to note that the first wave is not always the largest, and subsequent waves may arrive at intervals of 10 to 60 minutes, moving much faster than a person can run. The threat posed by a tsunami can persist for several hours following the arrival of the initial wave.

In contrast to other types of waves, tsunami waves generally do not curl or break. The coasts impacted by a tsunami will experience severe erosion. A tsunami can inundate areas hundreds of meters inland, with water moving with such force that it can demolish homes and other structures.

How Are Tsunamis Formed....

physical-characteristics-of-tsunamis

How Does an Earthquake Form a Tsunami?

 How Does an Earthquake Form a Tsunami?

Tsunamis

A tsunami occurs when a large body of water, such as an ocean or sea, experiences displacement that causes a long-wavelength wave of water to reach the shore. The most common cause of a tsunami is an underwater earthquake, but they can also be caused by other events, such as a volcano or underwater landslide. Tsunamis often occur without any warning, but monitoring stations in some areas of the world now allow scientists to issue tsunami warnings when conditions that could cause a tsunami are present.

Tectonic Earthquakes

Tectonic earthquakes are a common cause of tsunamis. They often occur in areas where two crustal plates are pushing against each other, forcing one plate to slide under the other. These earthquakes shift the crust of the earth, leading to a rapid drop or rise of sea floor. When this happens, the water directly above the shifting plate rises or falls as well, creating a wall that rises above the surrounding water. The rest of the water near it shifts to try and compensate for the sudden change. Because the area of sea floor that rises or falls is usually miles in length, the resulting water displacement also covers a large area. Larger earthquakes typically cause larger surface displacements and larger tsunamis.

Split Tsunamis

As the water tries to settle after an earthquake, the initial wall of water that originally formed splits into two waves. One travels outward across the deep ocean and the other travels toward the nearest shore. As the waves travel, they stretch out so they are not as tall, but are extremely long. They travel at the ocean surface and their speed depends on the depth of the ocean below them.

Tsunami Landing

As the tsunami comes close to a coastline, it encounters the continental slope, the place where the seafloor gradually rises up to the landmass. As it approaches land, the wavelength gets smaller and the amplitude gets larger, so it becomes taller and slower than when it was in open ocean. When it hits the shore, the wave usually causes a rapid rise of the entire coastline to far above the normal sea level.

How Does an Earthquake Form a Tsunami Video :

HOW ARE TSUNAMIS FORMED 2

HOW ARE TSUNAMIS FORMED 2 

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, which acts under the influence of gravity, attempts to regain its equilibrium. When large areas of the sea floor elevate or subside, a tsunami can be created. 

 Large vertical movements of the earth's crust can occur at plate boundaries. Plates interact along these boundaries called faults. Around the margins of the Pacific Ocean, for example, denser oceanic plates slip under continental plates in a process known as subduction. Subduction earthquakes are particularly effective in generating tsunamis. A tsunami can be generated by any disturbance that displaces a large water mass from its equilibrium position. In the case of earthquake-generated tsunamis, the water column is disturbed by the uplift or subsidence of the sea floor. 

Submarine landslides, which often accompany large earthquakes, as well as collapses of volcanic edifices, can also disturb the overlying water column as sediment and rock slump downslope and are redistributed across the sea floor. Similarly, a violent submarine volcanic eruption can create an impulsive force that uplifts the water column and generates a tsunami. Conversely, supermarine landslides and cosmic-body impacts disturb the water from above, as momentum from falling debris is transferred to the water into which the debris falls. Generally speaking, tsunamis generated from these mechanisms, unlike the Pacific-wide tsunamis caused by some earthquakes, dissipate quickly and rarely affect coastlines distant from the source area. How are tsunamis formed..

. what-is-tsunami

HOW ARE TSUNAMIS FORMED VIDEO :

How Are Tsunamis Formed

HOW ARE TSUNAMIS FORMED 

 A tsunami is a series of waves generated in an ocean or other body of water by a disturbance such as an earthquake, landslide, volcanic eruption, or meteorite impact. The picture at the left shows how an earthquake can generate a tsunami in the overlying water. Undersea earthquakes, which typically occur at boundaries between Earth’s tectonic plates, cause the water above to be moved up or down. Tsunami waves are formed as the displaced water, which acts under the influence of gravity, attempts to find a stable position again. 

Undersea landslides, which can be caused by large earthquakes, can also cause tsunami waves to form as water attempts to find a stable position. Undersea volcano eruptions can create enough force to uplift the water column and generate a tsunami. Asteroid impacts disturb the water from above, as momentum from falling debris is transferred to the water into which the debris falls. How Are Tsunamis Formed... physical-characteristics-of-tsunamis

How Are Tsunamis Formed Video :

HOW TSUNAMIS ARE FORMED

How Tsunamis Are Formed.. 

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 tCauses of tsunamishe deformed area is displaced from its equilibrium position. Waves are formed as the displaced water mass, which acts under the influence of gravity, attempts to regain its equilibrium. When large areas of the sea floor elevate or subside, a tsunami can be created. Large vertical movements of the earth's crust can occur at plate boundaries. Plates interact along these boundaries called faults. Around the margins of the Pacific Ocean, for example, denser oceanic plates slip under continental plates in a process known as subduction. Subduction earthquakes are particularly effective in generating tsunamis.

 A tsunami can be generated by any disturbance that displaces a large water mass from its equilibrium position. In the case of earthquake-generated tsunamis, the water column is disturbed by the uplift or subsidence of the sea floor. Submarine landslides, which often accompany large earthquakes, as well as collapses of volcanic edifices, can also disturb the overlying water column as sediment and rock slump downslope and are redistributed across the sea floor. Similarly, a violent submarine volcanic eruption can create an impulsive force that uplifts the water column and generates a tsunami. Conversely, supermarine landslides and cosmic-body impacts disturb the water from above, as momentum from falling debris is transferred to the water into which the debris falls. Generally speaking, tsunamis generated from these mechanisms, unlike the Pacific-wide tsunamis caused by some earthquakes, dissipate quickly and rarely affect coastlines distant from the source area. How Tsunamis are formed..

. how-tsunamis-form.

HOW TSUNAMIS ARE FORMED VIDEO:

What are Tsunamis?

What are Tsunamis?

A tsunami is a series of waves, generated in a body of water by an impulsive disturbance that vertically displaces the water column. Earthquakes, landslides, volcanic eruptions, explosions, and even the impact of cosmic bodies, such as meteorites, can generate tsunamis. Tsunamis can savagely attack coastlines, causing devastating property damage and loss of life.