What is a tsunami and what causes it? - In the wake of the 8.9 Sendai earthquake that affected the northeastern portion of Japan, the BBC reported that a massive tsunami took shape and drove a deluge of water inland. Even though the quake itself was centered off the Japanese coast, the resulting waves reached heights of up to 33 feet. Here are some must-know facts and figures about the creation and impact of tsunamis.
What is a tsunami?
It is a common misconception that a tsunami is one gigantic wave that destroys everything in its path before sweeping back into the ocean. Instead, the National Geophysical Data Center (NGDC) describes a tsunami as a "series of waves." The dangerous wave heights are coastal manifestations; an open ocean tsunami actually only rises up to a few inches or feet.
Earthquake-triggered tsunami washes away warehouse - An earthquake-triggered tsunami washes away a warehouse and vehicles in Kesennuma, Miyagi prefecture (state), Japan, Friday March 11, 2011. The ferocious tsunami spawned by one of the largest earthquakes ever recorded slammed Japan's eastern coasts
What causes tsunamis?
The series of waves that make up a tsunami is caused by a sudden disturbance that alters the seafloor. United States Search and Rescue Task Force officials note that earthquakes and occasionally also landslides force the upheaval of the water. Not every earthquake results in a tsunami; in fact, for these waves to form, the event must take place underneath the ocean floor or very close to it. Secondly, the earthquake must result in vertical seafloor movement.
How tall do tsunami waves get?
Depending on the size of the seafloor disturbance, its location and also the force of the energy that caused it, wave heights vary greatly. The NGDC compiled the characteristics of 26 tsunamis falling between 1906 and 1998; wave sizes ranged from approximately five feet to more than 175 feet. Combine this with a speed of about 500 miles per hour, and it stands to reason why these devastating waves are so dangerous to coastal communities.
What should I know if I live in a coastal area?
When moving into a home near the coast, learn about local tsunami evacuation routes and warning systems. If there are no officially marked routes or designated safety areas, know how far away from the ocean your residence is located and how high above sea level you actually are. Emergency alerts -- usually conveyed via radio and television -- alert of evacuations for residents by using these values. If an evacuation order is issued, do not head to the beach, pier or scenic outlook. Instead, head inland for higher ground.
Are there warnings signs I can see?
In the absence of official warnings, there are natural signs that the seafloor has been disturbed and a tsunami might be imminent. An unexplained rumbling sound, a sudden withdrawal of the waters past the usual coast line and also a rapid rise in water level are indicators of a possible series of waves coming in. ( news.yahoo.com )
What is a tsunami?
It is a common misconception that a tsunami is one gigantic wave that destroys everything in its path before sweeping back into the ocean. Instead, the National Geophysical Data Center (NGDC) describes a tsunami as a "series of waves." The dangerous wave heights are coastal manifestations; an open ocean tsunami actually only rises up to a few inches or feet.
Earthquake-triggered tsunami washes away warehouse - An earthquake-triggered tsunami washes away a warehouse and vehicles in Kesennuma, Miyagi prefecture (state), Japan, Friday March 11, 2011. The ferocious tsunami spawned by one of the largest earthquakes ever recorded slammed Japan's eastern coasts
What causes tsunamis?
The series of waves that make up a tsunami is caused by a sudden disturbance that alters the seafloor. United States Search and Rescue Task Force officials note that earthquakes and occasionally also landslides force the upheaval of the water. Not every earthquake results in a tsunami; in fact, for these waves to form, the event must take place underneath the ocean floor or very close to it. Secondly, the earthquake must result in vertical seafloor movement.
How tall do tsunami waves get?
Depending on the size of the seafloor disturbance, its location and also the force of the energy that caused it, wave heights vary greatly. The NGDC compiled the characteristics of 26 tsunamis falling between 1906 and 1998; wave sizes ranged from approximately five feet to more than 175 feet. Combine this with a speed of about 500 miles per hour, and it stands to reason why these devastating waves are so dangerous to coastal communities.
What should I know if I live in a coastal area?
When moving into a home near the coast, learn about local tsunami evacuation routes and warning systems. If there are no officially marked routes or designated safety areas, know how far away from the ocean your residence is located and how high above sea level you actually are. Emergency alerts -- usually conveyed via radio and television -- alert of evacuations for residents by using these values. If an evacuation order is issued, do not head to the beach, pier or scenic outlook. Instead, head inland for higher ground.
Are there warnings signs I can see?
In the absence of official warnings, there are natural signs that the seafloor has been disturbed and a tsunami might be imminent. An unexplained rumbling sound, a sudden withdrawal of the waters past the usual coast line and also a rapid rise in water level are indicators of a possible series of waves coming in. ( news.yahoo.com )
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