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View Full Version : Why Was the February 27, 2010 Tsunami Smaller than Expected?



Fraser
2010-Mar-01, 01:20 AM
While a huge earthquake off the coast of Chile triggered a tsunami that moved at the speed of a jet aircraft across the Pacific Ocean on Feb. 27, the event thankfully — was smaller scientists expected. Some experts forecasted the event would produce 9-foot tall tsunami waves slamming coastlines along the Pacific Rim. [...]

More... (http://www.universetoday.com/2010/02/28/why-was-the-february-27-2010-tsunami-smaller-than-expected/)

aurora
2010-Mar-01, 02:43 AM
My guess, it wasn't a shallow quake.

TheHalcyonYear
2010-Mar-01, 02:44 AM
In other words, we can't track them so we have to rely on our computer models. Something's wrong with them so when all the data is in, we will have to revise the models.

Rhaedas
2010-Mar-01, 03:32 AM
Some people are already complaining the warnings were wrong and the evacuations were unnecessary. Do they not want warnings at all?

Yes, we're still learning about how to better the models we do have, and we'll probably never have enough information at the time of occurrence to be perfectly accurate, but I'd rather inconvenience a lot of people for a few hours than hope nothing happens and be wrong.

Getting back to the science, is there really a good way to predict how much of an upwelling is to be expected without actually seeing the rock displacement itself? We know how fast the wave will move through water from a point, and I believe we can track the wave front with appropriate buoy sensors, but I don't think that alone can tell us the energy in that wave, and how its impact on a shoreline will be.

TheHalcyonYear
2010-Mar-01, 08:00 AM
Warnings are fine. One will find, however, that incorrect warnings are going to damage the cause. You'd rather inconvenience a lot of people, but those people may not see it the same way. It wasn't just a few hours of inconvenience. The recent warning cost a some people a lot of money in Hawaii. I agree that things could have turned out a lot differently, but for the people who are going to bear the cost that's probably going to be cold comfort.

George
2010-Mar-02, 03:53 AM
Since the quake was in shallow water, it did not have the column of water necessary to produce monster waves, unlike the Sumatra tsunami.

aurora
2010-Mar-02, 03:07 PM
Since the quake was in shallow water, it did not have the column of water necessary to produce monster waves, unlike the Sumatra tsunami.

The epicentre was what, 35 KM under the surface of the ground?

That 35 KM of rock absorbed a lot of the vertical movement that would have caused a larger tsunami.

George
2010-Mar-02, 10:15 PM
The epicentre was what, 35 KM under the surface of the ground?

That 35 KM of rock absorbed a lot of the vertical movement that would have caused a larger tsunami. It is a matter of how much column of water is moved upward then suddenly dropped. There simply wasn't deep enough water in the lift zone to present a massive and sudden drop of this column of water, thus the tsunami was a more limited one. [This is what I heard on the radio by some expert on this quake, but I haven't researched his claim.]