FAQ - Frequently Asked Questions:
**For questions about the December 2004 Sumatra Tsunami please click here**
What is a tsunami? What causes tsunamis? How do tsunamis behave?
Please see http://www.ess.washington.edu/tsunami/general/physics/physics.html
Is there any way to prevent a tsunami?
No. Tsunamis are natural phenomena and can not be prevented. What can be prevented, however, are some of the casualties and damage that tsunamis cause. To read what to do to prepare for a tsunami see http://www.fema.gov/hazards/tsunamis/tsunamif.shtm . For what to do during a tsunami see http://pubs.usgs.gov/circ/c1187/
When was the first tsunami?
As long as there has been water on earth, there have been tsunamis. All it takes to generate a tsunami is a body of water (lake, ocean. etc.) and a large undersea motion (such as seimic uplift, landslides etc.) see . Tsunamis have occurred since long before humans started writing down history. This question is similar to asking when was the first earthquake, the first hurricane, the first tornado? These events are all natural phenomena that are just part of the physics of the earth.
How many tsunamis have there been? How often do they happen?
If you would like to know about all the historic tsunamis scientists have been studying, an excellent site for this information is a website of the Siberian division of the Russian Academy of Sciences (Institute of Computational Mathematics and Mathematical Geophysics) at http://omzg.sscc.ru/tsulab/ . For the Pacific Ocean alone, this site lists over 1490 tsunami events that date back to as early as 47 B.C. For the years 1904 - 2004, the catalog lists about 640 events. This averages out to 6 or 7 tsunami-causing events a year. Not all of these events generated large amounts of damage but most had at least some local effects.
What was the biggest tsunami?
First of all we can only talk about tsunamis for which we have the facts: the well-documented historic tsunamis. We have reasonably good facts for tsunamis in the last 100 years. Second, as usual, the answer to this question depends on what you mean by "biggest."
The biggest Tsunami Magnitude in the last century was probably the 1960 Chile tsunami . The tsunami magnitude refers to the amount of energy released during generation and corresponds roughly to the largest amount of water moved.
The tsunami wave with the highest runup (biggest splash) in the last century was probably at 1958 Lituya Bay, Alaska. A good source of information on this landslide-caused tsunami can be found at http://www.usc.edu/dept/tsunamis/alaska/1958/webpages/index.html
The tsunami that caused the most damage and human casualties in the last century is the recent 2004 Sumatra tsunami.
These are only the tsunamis for which there are historical facts and measurements. Other tsunamis have occured throughout history and pre-history that were most likely bigger than the ones listed above. One of the research tasks of scientists studying tsunamis is to find out more about ancient tsunamis.
Who is the author of this site? How do I reference the materials?
The Tsunami! site is maintained by the Department of Earth and Space Sciences at the University of Washington. It is usually sufficient to reference the department and university. This website is currently being upgraded. A large portion of the material for the Tsunami! browser was originally written in 1995 by Benjamin Cook, at that time a Master's student in Civil Engineering at the University of Washington. The text on physics of tsunamis is largely his own original words. Where we used video, text or photographs from other sources, the sources are referenced on the relevant page. (for example: the sources for for some historic tsunami events are listed in http://www.ess.washington.edu/tsunami/references.html ) If you would like to specifically reference the author for a particular page or graphic and cannot tell where it came from, please contact us.
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or you can e-mail us for help with a specific question. Please be advised that questions are not answered on-line or in real time. Questions are answered by tsunami experts on their own time, and as time permits. We will do our best to get back to you in a day or two but answers can take longer if we are not available.