Chile tsunami

Twenty-four hours after the Chilean earthquake, the resulting tsunami has rolled across the Pacific Ocean to wash up on the shores of Japan and Alaska. It was easily managed nearly everywhere it hit, almost always less than a meter in amplitude. (Note: amplitude means height above normal sea level, not crest-to-trough wave height.)

The news services are no doubt disappointed to have so little to report on, after all the hype and on-the-scene cameras. But the truth is, tsunamis happen on a regular basis, all over the world, just like earthquakes. And just like earthquakes, the vast majority of these tsunamis are only detectable by scientific measuring equipment. But the public perception is always of the gigantic wave, because small is not memorable.

Small is memorable to people who have seen the power of even a 2-meter tsunami. Yesterday’s tsunami showed its greatest amplitude in the port city of Talcahuano, Chile, where it reached 2.34 meters (7.7 feet) above normal sea level. Here is what 2.34 meters can do:

The Big Picture at Boston.com has a set of 35 photographs of the earthquake damage in Chile. The last three were taken in Talcahuano, and are an excellent lesson in why the governments around the Pacific Rim were wise to evacuate their low-lying areas. Even a small tsunami is not to be taken lightly.

About these ads

About oregon expat

Socialist heathen and Mac-using writer who enjoys pondering science, politics, well-honed satire (though sarcastic humor can work, too) and all things geeky.
This entry was posted in science. Bookmark the permalink.

4 Responses to Chile tsunami

  1. Inge says:

    That same article (http://www.hln.be/hln/nl/6396/Aardbeving-en-tsunami-Chili/article/detail/1073531/2010/02/28/Tsunami-zet-Japanse-haven-onder-water-24-uur-na-Chili.dhtml) is also claiming that on Hiva Oa the waves were 4m.
    And it’s talking about some other islands (Robinson Crusoe, Juan Fernandez) where is also some significant damage.

    Maybe these aren’t ‘famous’ a name as Japan, but i wouldn’t call it small.

    • oregon expat says:

      The PTWC reported a wave amplitude of 1.79 meters for Hiva Oa — half a meter less than Talcahuano. The article you reference is almost certainly quoting wave heights, not amplitude.

      How a tsunami manifests itself upon landfall can vary dramatically depending on local geographic conditions. For instance, a wave arriving in a broad, flat harbor will have a much lower height than the same wave arriving in a narrow, walled area, or an area where the ground abruptly rises. I don’t doubt that a 1.79-meter tsunami could double its height if it were channeled by local geography.

  2. Ana says:

    Thank you for your straightforward explanations and considerations in this and in your previous post, Fletcher. In natural disasters, there are the facts, there are the people and there are the media.

  3. Inge says:

    True. Media always try to ‘spin’ a story. Still i think we haven’t really heard the true cost of both the quake as the tsunami yet. Too many areas are not communicating, which isn’t a good sign.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s