The most common source of a tsunami is an earthquake, although it can also be brought on by a meteorite, landslide, volcanic eruption, or abrupt changes in atmospheric pressure.1)
A “wave train”—a series of waves collectively known as a tsunami—is what causes a tsunami. The “wave period,” which can last anywhere from a few minutes to two hours, is the interval between waves. Typically, the initial wave is not the strongest, and subsequent waves, like the fifth or sixth, may be much bigger.2)
For the first time, Greek historian Thucydides (460–395 B.C.) connected undersea earthquakes to tsunamis in his History of the Peloponnesian War.3)
Tsunami waves frequently only reach heights of one to three feet in the deepest parts of the ocean. It's possible for sailors to be completely unaware that a tsunami is passing under them.4)
Within 160 miles (250 km) of the tsunami's origin or within 30 minutes of the tsunami's generation, around 99% of all tsunami-related fatalities have occurred. Therefore, everyone in a coastal location should heed the natural signal that a tsunami may be approaching and escape low-lying coastal areas if they experience a significant earthquake.5)
The ocean may suddenly seem to drain away up to 30 minutes before a tsunami hits, although this is not always the case. The term “drawback” refers to the water receding as the tsunami's crest approaches the beach.6)
Hawaii, Alaska, Washington, Oregon, and California are the U.S. states most at risk from tsunamis.7)
On May 22, 1960, a massive earthquake struck more than 100 miles off the coast of Chile. 80-foot waves hit the beachfront within 15 minutes after the 9.5 quake. Hawaii was hit by tsunami waves fifteen hours after the earthquake, while Japan was hit by the tsunami 22 hours later, 10,000 miles away.8)
No one has ever seen a meteorite-induced tsunami, but many scientists believe that such an event may have wiped out all life on Earth more than 3.5 billion years ago.9)
While the speed of wind-generated waves can range from 2 to 60 miles (3.2 to 97 km/h), the speed of a jet airliner, tsunami waves can reach 600 miles (970 km/h).10)
The Indian Ocean was reportedly hit by an asteroid some 4,800 years ago, according to scientists. It is estimated that the resulting wave was around 600 feet (180 m) high.11)
When a lighter tectonic plate is driven over a heavier plate or along subduction zones, tsunamis are caused by earthquakes. The whole water column above the ocean floor is moved by a quick rise or decrease in the ocean floor. A tsunami is caused by the ocean's level fluctuating above the earthquake. In most cases, if the tectonic plates split apart or glide past one other, a tsunami won't form.12)
With their long, exposed trunks, palm trees are perfectly suited to life on the beach and frequently survive tsunamis unharmed.13)
More than 216,000, and potentially as many as 283,000, people perished in the 2004 Indian Ocean tsunami.14)
The region of inundation is the furthest inland (horizontally) point that is inundated by tsunami waters.15)
The run-up is the name given to the vertically highest point that the water reaches.16)
The Canary Islands may be the site of the upcoming mega-tsunami, according to scientists. With waves reaching more than 100 feet high, the super tsunami might traverse the Atlantic Ocean and destroy U.S. coastal towns including New York, Boston, and Miami.17)
A landslide is typically to blame for “mega-tsunamis”, which are tsunamis with incredibly tall waves.18)
The largest tsunami ever measured, at 1,700 feet (534 m), was created by a mega-tsunami in Lituya Bay in Alaska in 1958. Amazingly, just two persons passed away.19)
If you are trapped in a tsunami wave, it is best to grasp hold of something floating and let the current take you rather than trying to swim.20)
Similar to tsunamis, seiches (SAYSH uhz) happen in contained bodies of water like lakes or inland seas as opposed to seas and oceans. They typically cause less damage and are smaller than tsunamis. The most frequent reason for seiches is wind.21)
Japanese for tsunami is “harbor wave” (tsu = harbor + nami = wave), which reflects Japan's history of frequent tsunamis.22)
The average speed of a tsunami when it strikes coastal locations is roughly 22 mph (35 km/h). Depending on the terrain along the shore and the slope of the beach, the pace as it flows inland differs significantly. The force of the tsunami backwash can be comparable to or even greater than the original impact in some circumstances.23)
The Indonesian 9.0 earthquake in 2004 released more energy than all the earthquakes on the planet in the last 25 years combined. A segment of seafloor the size of the state of California moved upward and seaward by more than 30 feet, displacing huge amounts of water.24)
On March 28, 1964, an earthquake measuring 8.4 on the Richter scale rocked Alaska, causing the costliest tsunami to ever hit the western United States and Canada. More than 120 individuals died as a result of waves that rose as high as 21 feet.25)
Hawaii is the state most at risk from a tsunami. About once a year, and once every seven years, a destructive tsunami hits Hawaii. A destructive tsunami occurs in California, Oregon, and Washington roughly every 18 years.26)
Women and children made up a large portion of the tsunami victims in the Indian Ocean in 2004. Children were apparently too feeble to battle the powerful currents, and many women were reportedly waiting along the beaches for their husbands to return from fishing.27)
Mahabalipuram, the capital of a strong monarchy that traded with China, Rome, Greece, Arabia, and Egypt about 1,500 years ago, was lost until the Indian Ocean tsunami of 2004 revealed it.28)
By leaving behind significant amounts of salt, tsunamis can contaminate freshwater surface and groundwater systems as well as soil. As a result, thousands of people may still perish from sickness and malnutrition years after the tsunami.29)
Although tsunamis have been reported in every ocean on Earth, the Pacific “Ring of Fire” accounts for around 80% of all documented tsunamis.30)
The force of a tsunami on land is thousands of times greater than that of a typical wave. Wind pushing water at an ocean's or other body of water's surface produces regular waves. An incident that impacts the whole water column, from the ocean floor to its surface, causes tsunami waves.31)